I have fitted a/c system to my '87 BMW from a wrecked car. It was filled
with oil, UV die, and R-12. Few days later it does not blow cold. Looks
like I have a leak somewhere, and my R-12 escaped.

I bought UV-lamp and goggles and it looks like my condenser has a leak,
and also a low side valve. But a/c shop spilled some UV die around the
engine bay and tried to rinse it off with water. So now I am not sure
that what I see is a leak or it was just not rinsed away.

I tried to clean it by spraying it with warm water and liquid
dishwashing detergent, and a bit later rinsing it off with a garden
hose. I did nothing. So how do you rinse UV die off?


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In article ,
   Yvan  wrote:
> I tried to clean it by spraying it with warm water and liquid
> dishwashing detergent, and a bit later rinsing it off with a garden
> hose. I did nothing. So how do you rinse UV die off?

Any of the usual solvents, I'd guess. White spirit might be the easiest.

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Yvan wrote:
> I have fitted a/c system to my '87 BMW from a wrecked car. It was
> filled with oil, UV die, and R-12. Few days later it does not blow
> cold. Looks like I have a leak somewhere, and my R-12 escaped.
>
> I bought UV-lamp and goggles and it looks like my condenser has a
> leak, and also a low side valve. But a/c shop spilled some UV die
> around the engine bay and tried to rinse it off with water. So now I
> am not sure that what I see is a leak or it was just not rinsed away.
>
> I tried to clean it by spraying it with warm water and liquid
> dishwashing detergent, and a bit later rinsing it off with a garden
> hose. I did nothing. So how do you rinse UV die off?

they make actual dye solvent, any ac place will have it, called dye-b-gone 
or something similar.

On Sun, 27 Jul 2008 13:55:25 +0100, Yvan  wrote:

> I have fitted a/c system to my '87 BMW from a wrecked car. It was filled
> with oil, UV die, and R-12. Few days later it does not blow cold. Looks
> like I have a leak somewhere, and my R-12 escaped.
>
> I bought UV-lamp and goggles and it looks like my condenser has a leak,
> and also a low side valve. But a/c shop spilled some UV die around the
> engine bay and tried to rinse it off with water. So now I am not sure
> that what I see is a leak or it was just not rinsed away.
>
> I tried to clean it by spraying it with warm water and liquid
> dishwashing detergent, and a bit later rinsing it off with a garden
> hose. I did nothing. So how do you rinse UV die off?
>
>


They've all got "amusing" names like dye-away, dye-free or glo-cleaner
http://www.joetoolcompany.com/tratp90000008.html

Nedavno Mrcheerful napisa:

> > So how do you rinse UV die off?
> 
> they make actual dye solvent, any ac place will have it, called
> dye-b-gone or something similar. 


I was thinking of some DIY solution (where I am it is not easy to find
what you are talking about), something like suggested white spirit.


BTW i tried to rinse condenser with petrol, and it worked. I got it
(almost) completely off, and I am going to test it now for leaks.


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Yvan wrote:
> Nedavno Mrcheerful napisa:
>
>>> So how do you rinse UV die off?
>>
>> they make actual dye solvent, any ac place will have it, called
>> dye-b-gone or something similar.
>
>
> I was thinking of some DIY solution (where I am it is not easy to find
> what you are talking about), something like suggested white spirit.
>
>
> BTW i tried to rinse condenser with petrol, and it worked. I got it
> (almost) completely off, and I am going to test it now for leaks.

I would think a pressure washer or steam cleaner will do the job ok, but 
make sure there is pressure in the system first or you will damage the whole 
system with the water.

the usual way to test will be to pressurise with Nitrogen. or use a gas 
sniffer if there is any refrigerant pressure left.

Nedavno Mrcheerful napisa:

> I would think a pressure washer or steam cleaner will do the job ok,
> but make sure there is pressure in the system first or you will
> damage the whole system with the water.


You mean that I have pressure in the a/c system so that water does not
get inside trough leak point? If so I still have pressure, as it still
blows cold air, but not cold enough. And I can see liquid refrigerant
with bubbles at the sight-glass.


> the usual way to test will be to pressurise with Nitrogen. or use a
> gas sniffer if there is any refrigerant pressure left.

I do not have access to a gas sniffer, but UV die is inside, so UV-lamp
and goggles should be OK.





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Yvan wrote:
> Nedavno Mrcheerful napisa:
>
>> I would think a pressure washer or steam cleaner will do the job ok,
>> but make sure there is pressure in the system first or you will
>> damage the whole system with the water.
>
>
> You mean that I have pressure in the a/c system so that water does not
> get inside trough leak point? If so I still have pressure, as it still
> blows cold air, but not cold enough. And I can see liquid refrigerant
> with bubbles at the sight-glass.

yes, moisture in the system is a major no-no, for several reasons.

bubbles visible is not abnormal.

Once you have replaced the leaking bits plus the dryer the correct procedure 
is to vacuum down and make sure vacuum can be held, then fill with the 
correct amount of fresh gas plus oil/dye/leakstop as needed.  then test, get 
the running pressures and ambient and delivered temperatures and check them 
against the ideals from the makers.

Mrcheerful

Nedavno Mrcheerful napisa:

> yes, moisture in the system is a major no-no, for several reasons.
> 
> bubbles visible is not abnormal.
> 
> Once you have replaced the leaking bits plus the dryer the correct
> procedure is to vacuum down and make sure vacuum can be held, then
> fill with the correct amount of fresh gas plus oil/dye/leakstop as
> needed.  then test, get the running pressures and ambient and
> delivered temperatures and check them against the ideals from the
> makers.


Yes, I know all that, thank you.

Any tips on how to change oil in complete system? Or, since I am
probably going to change condenser and evaporator, how to drain oil
from the compressor?

I am asking this since a/c shop filled the system with R-134, not with
R-12 as they should. They claim that oil is compatible with both R-12
and R134, but I do not trust them any more. So now I have new dryer, a
bottle of R-12 and a can of mineral a/c oil.

Is there a drain plug ore something on the compressor? Or do I need to
get it off?


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Yvan wrote:
> Nedavno Mrcheerful napisa:
>
>> yes, moisture in the system is a major no-no, for several reasons.
>>
>> bubbles visible is not abnormal.
>>
>> Once you have replaced the leaking bits plus the dryer the correct
>> procedure is to vacuum down and make sure vacuum can be held, then
>> fill with the correct amount of fresh gas plus oil/dye/leakstop as
>> needed.  then test, get the running pressures and ambient and
>> delivered temperatures and check them against the ideals from the
>> makers.
>
>
> Yes, I know all that, thank you.
>
> Any tips on how to change oil in complete system? Or, since I am
> probably going to change condenser and evaporator, how to drain oil
> from the compressor?
>
> I am asking this since a/c shop filled the system with R-134, not with
> R-12 as they should. They claim that oil is compatible with both R-12
> and R134, but I do not trust them any more. So now I have new dryer, a
> bottle of R-12 and a can of mineral a/c oil.
>
> Is there a drain plug ore something on the compressor? Or do I need to
> get it off?

Original oil is not compatible, there are replacement types that are.

There are special flushing kits available to get all the old junk out.

You need to remove the compressor, turn it upside down, let the oil all fall 
out, rotating the compressor as needed.

Nedavno Mrcheerful napisa:

> You need to remove the compressor, turn it upside down, let the oil
> all fall out, rotating the compressor as needed.


OK, thank you.


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On Mon, 28 Jul 2008 06:05:51 +0100, Yvan  wrote:

> Nedavno Mrcheerful napisa:
>
>> You need to remove the compressor, turn it upside down, let the oil
>> all fall out, rotating the compressor as needed.
>
>
> OK, thank you.
>
>


Then vacuum the sytem down before putting anything back in. (tool hire  
shops rent vacuum pumps for diamond drilling rigs if you've not got anyone  
helpfull nearby)

I have another question.

Before R-12 escaped, while a/c system was fully charged, it would not
blow colder than ~14 deg Celsius (Fan set on high, car in the garage -
not in the sun, ambient temperature ~30C). High pressure pipe warm,
low side cold and wet. Compressor does not cycle on and off, it's on
constantly. Very little, almost no water under the car from
condensation. After few days it was colder ~17C and I could hear a
click under the dash, and revs and load would go down, so I guess that
icing prevention is OK.

I was told at another ng that this might happen if evaporator is dirty
(I do not have a/c filter in this car). I do not see logic there. If it
was dirty, less air would go around it, it would ice-up, and compressor
should stop. And if icing happens when I set fan to high (or switch a/c
off) it should melt, and there should be some water underneath the car.

Any thoughts on this?



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On Mon, 28 Jul 2008 20:51:10 +0100, Yvan  wrote:

> I have another question.
>
> Before R-12 escaped, while a/c system was fully charged, it would not
> blow colder than ~14 deg Celsius (Fan set on high, car in the garage -
> not in the sun, ambient temperature ~30C). High pressure pipe warm,
> low side cold and wet. Compressor does not cycle on and off, it's on
> constantly. Very little, almost no water under the car from
> condensation. After few days it was colder ~17C and I could hear a
> click under the dash, and revs and load would go down, so I guess that
> icing prevention is OK.
>
> I was told at another ng that this might happen if evaporator is dirty
> (I do not have a/c filter in this car). I do not see logic there. If it
> was dirty, less air would go around it, it would ice-up, and compressor
> should stop.

not if it's coated in dirt rather than clogged with dirt. However it  
sounds more likely that you're low on coolant


> And if icing happens when I set fan to high (or switch a/c
> off) it should melt, and there should be some water underneath the car.
>
> Any thoughts on this?
>
>
>

Nedavno Duncan Wood napisa:

> > I was told at another ng that this might happen if evaporator is
> > dirty (I do not have a/c filter in this car). I do not see logic
> > there. If it was dirty, less air would go around it, it would
> > ice-up, and compressor should stop.  
> 
> not if it's coated in dirt rather than clogged with dirt. However it  
> sounds more likely that you're low on coolant


No, I have enough R-12 in the system, I have a bottle of R-12, and I
added ~1kg as it says in the manual (no bubbles in sight-glass).

And what happens if evaporator is coated in dirt?


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On Tue, 29 Jul 2008 05:44:28 +0100, Yvan  wrote:

> Nedavno Duncan Wood napisa:
>
>> > I was told at another ng that this might happen if evaporator is
>> > dirty (I do not have a/c filter in this car). I do not see logic
>> > there. If it was dirty, less air would go around it, it would
>> > ice-up, and compressor should stop.
>>
>> not if it's coated in dirt rather than clogged with dirt. However it
>> sounds more likely that you're low on coolant
>
>
> No, I have enough R-12 in the system, I have a bottle of R-12, and I
> added ~1kg as it says in the manual (no bubbles in sight-glass).
>
> And what happens if evaporator is coated in dirt?
>
>


Then the dirt insulates it from the air.

Yvan wrote:
> Nedavno Duncan Wood napisa:
>
>>> I was told at another ng that this might happen if evaporator is
>>> dirty (I do not have a/c filter in this car). I do not see logic
>>> there. If it was dirty, less air would go around it, it would
>>> ice-up, and compressor should stop.
>>
>> not if it's coated in dirt rather than clogged with dirt. However it
>> sounds more likely that you're low on coolant
>
>
> No, I have enough R-12 in the system, I have a bottle of R-12, and I
> added ~1kg as it says in the manual (no bubbles in sight-glass).
>
> And what happens if evaporator is coated in dirt?

Was the system vacuumed correctly before adding the refrigerant?
 If you have just fitted all this lot then I would assume you know the 
condition of the parts and that they were clean.

Nedavno Duncan Wood napisa:

> > And what happens if evaporator is coated in dirt?
> 
> 
> Then the dirt insulates it from the air.


So it blows warm... And why is the compressor always on? Why ice
preventing sensor does not kick in and power off the compressor? And
there should be some water sipping out the drain hoses.



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On Tue, 29 Jul 2008 16:35:04 +0100, Yvan  wrote:

> Nedavno Duncan Wood napisa:
>
>> > And what happens if evaporator is coated in dirt?
>>
>>
>> Then the dirt insulates it from the air.
>
>
> So it blows warm... And why is the compressor always on?

Because the airs hot.

> Why ice
> preventing sensor does not kick in and power off the compressor?

Because it's not iced up.

> And
> there should be some water sipping out the drain hoses.
>
>
>

Only if the airs being chilled enough.

Nedavno Mrcheerful napisa:

> Was the system vacuumed correctly before adding the refrigerant?

I think that it wasn't. Another reason for me trying to do the work...


>  If you have just fitted all this lot then I would assume you know
> the condition of the parts and that they were clean. 

It looked clean, but for the start I connected all together just to
see if it will work. It came in few bits: one under the dash with
heater , evaporator, flaps... then the compressor, condenser  and
hoses. I bought new dryer.

I guess that if I want to get it working as it should, I'll have to get
that manifold with gauges next...



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Nedavno Duncan Wood napisa:

> >> Then the dirt insulates it from the air.  
> >
> >
> > So it blows warm... And why is the compressor always on?  
> 
> Because the airs hot.
> 
> > Why ice
> > preventing sensor does not kick in and power off the compressor?  
> 
> Because it's not iced up.
> 
> > And
> > there should be some water sipping out the drain hoses.
> >  
> 
> Only if the airs being chilled enough.


How could it blow warm, with evaporetor not iced up, and compressor
running constantly? Something must be cold, condenser is hot.


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On Tue, 29 Jul 2008 16:47:28 +0100, Yvan  wrote:

> Nedavno Duncan Wood napisa:
>
>> >> Then the dirt insulates it from the air.
>> >
>> >
>> > So it blows warm... And why is the compressor always on?
>>
>> Because the airs hot.
>>
>> > Why ice
>> > preventing sensor does not kick in and power off the compressor?
>>
>> Because it's not iced up.
>>
>> > And
>> > there should be some water sipping out the drain hoses.
>> >
>>
>> Only if the airs being chilled enough.
>
>
> How could it blow warm, with evaporetor not iced up, and compressor
> running constantly? Something must be cold, condenser is hot.
>
>


The inside of the evaporator is cold, then there's a layer of crap then  
there's some slightly cold air. The ice should be on the outside of the  
evaporator from the cold air, if there's ice inside then everything's  
fucked.


  Assuming the pressures inside are adequate, if you've got a gas leak  
you'll get a hot condensor & a cool evaporator.

Nedavno Duncan Wood napisa:

> Assuming the pressures inside are adequate, if you've got a gas leak  
> you'll get a hot condensor & a cool evaporator.


Even with a small leak? The one such that coolant does not leak for a
week or so?


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Nedavno Duncan Wood napisa:

> The ice should be on the outside of the  
> evaporator from the cold air, if there's ice inside then
> everything's fucked.


How does the ice build up inside?


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On Tue, 29 Jul 2008 16:59:50 +0100, Yvan  wrote:

> Nedavno Duncan Wood napisa:
>
>> Assuming the pressures inside are adequate, if you've got a gas leak
>> you'll get a hot condensor & a cool evaporator.
>
>
> Even with a small leak? The one such that coolant does not leak for a
> week or so?
>
>


Fairly quickly, yes.

On Tue, 29 Jul 2008 17:00:55 +0100, Yvan  wrote:

> Nedavno Duncan Wood napisa:
>
>> The ice should be on the outside of the
>> evaporator from the cold air, if there's ice inside then
>> everything's fucked.
>
>
> How does the ice build up inside?
>
>


It shouldn't, that's what the drier & vacuuming it's for. The ice sensor  
only detects when the outside of the evaporators covered in ice, whichonly  
happens when it really chills the incoming air.

Nedavno Duncan Wood napisa:

> >> Assuming the pressures inside are adequate, if you've got a gas
> >> leak you'll get a hot condensor & a cool evaporator.  
> >
> >
> > Even with a small leak? The one such that coolant does not leak for
> > a week or so?
> >
> >  
> 
> 
> Fairly quickly, yes.


Reading this again, condensor should be hot and evaporator cool... Or
cold?



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Nedavno Duncan Wood napisa:

> > How does the ice build up inside?
> >
> >  
> 
> 
> It shouldn't, that's what the drier & vacuuming it's for. The ice
> sensor only detects when the outside of the evaporators covered in
> ice, whichonly happens when it really chills the incoming air.


I guess I'll have to get new condenser evaporator and dryer and start
again :-( It is going to be expensive :-(


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On Tue, 29 Jul 2008 17:06:41 +0100, Yvan  wrote:

> Nedavno Duncan Wood napisa:
>
>> > How does the ice build up inside?
>> >
>> >
>>
>>
>> It shouldn't, that's what the drier & vacuuming it's for. The ice
>> sensor only detects when the outside of the evaporators covered in
>> ice, whichonly happens when it really chills the incoming air.
>
>
> I guess I'll have to get new condenser evaporator and dryer and start
> again :-( It is going to be expensive :-(
>
>


Get it vacuumed & fix the leak, you shouldn't need to change all of it.

On Tue, 29 Jul 2008 17:04:58 +0100, Yvan  wrote:

> Nedavno Duncan Wood napisa:
>
>> >> Assuming the pressures inside are adequate, if you've got a gas
>> >> leak you'll get a hot condensor & a cool evaporator.
>> >
>> >
>> > Even with a small leak? The one such that coolant does not leak for
>> > a week or so?
>> >
>> >
>>
>>
>> Fairly quickly, yes.
>
>
> Reading this again, condensor should be hot and evaporator cool... Or
> cold?
>
>
>


If it's working ,hot & cold.

Nedavno Duncan Wood napisa:

> > I guess I'll have to get new condenser evaporator and dryer and
> > start again :-( It is going to be expensive :-(
> 
> 
> Get it vacuumed & fix the leak, you shouldn't need to change all of
> it.


How do you fix a leak at the condenser? I have UV light and goggles,
and it shows a leak at the condenser near the connectors for the hose.
I think that it can not be repaired, I need to replace it.

I also found traces of the UV die at the drain hoses, so I guess that
evaporator is leaking too. I'll check that when I find some time to take
evaporator out.

And another leak is the valve on the low side. I changed the needle
(the small part that you can undo with the metal cap from a tire
valve), but it leaks again. What can I do to stop it? There is a cap
that is screwed on there, is that enough, since it's the low side, not
much pressure there?


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Yvan wrote:
> Nedavno Duncan Wood napisa:
>
>>> I guess I'll have to get new condenser evaporator and dryer and
>>> start again :-( It is going to be expensive :-(
>>
>>
>> Get it vacuumed & fix the leak, you shouldn't need to change all of
>> it.
>
>
> How do you fix a leak at the condenser? I have UV light and goggles,
> and it shows a leak at the condenser near the connectors for the hose.
> I think that it can not be repaired, I need to replace it.
>
> I also found traces of the UV die at the drain hoses, so I guess that
> evaporator is leaking too. I'll check that when I find some time to
> take evaporator out.
>
> And another leak is the valve on the low side. I changed the needle
> (the small part that you can undo with the metal cap from a tire
> valve), but it leaks again. What can I do to stop it? There is a cap
> that is screwed on there, is that enough, since it's the low side, not
> much pressure there?

If the O rings and hoses were not changed to R134a compatible items then you 
would have leaks all over the place.   All O rings should be green not 
black.  You may find that some of the leaks will stop with plain r12 in the 
system.  Without a manifold set and a vacuum pump you really are stabbing in 
the dark at getting it to work at all.

Get a proper valve, not a tyre valve for the leaking fill port, the cap is 
really only a dust cap

Nedavno Mrcheerful napisa:

> If the O rings and hoses were not changed to R134a compatible items
> then you would have leaks all over the place.   All O rings should be
> green not black.  You may find that some of the leaks will stop with
> plain r12 in the system.  Without a manifold set and a vacuum pump
> you really are stabbing in the dark at getting it to work at all.
> 
> Get a proper valve, not a tyre valve for the leaking fill port, the
> cap is really only a dust cap 


I filled the system with R-12 so it can not be a problem. And I plan to
get a manifold set before soon.

I did not put a tire valve, it just looks like one. I found a proper
valve in the a/c shop. But it is still leaking.

And can condenser leak be repaired?


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Yvan wrote:
> Nedavno Mrcheerful napisa:
>
>> If the O rings and hoses were not changed to R134a compatible items
>> then you would have leaks all over the place.   All O rings should be
>> green not black.  You may find that some of the leaks will stop with
>> plain r12 in the system.  Without a manifold set and a vacuum pump
>> you really are stabbing in the dark at getting it to work at all.
>>
>> Get a proper valve, not a tyre valve for the leaking fill port, the
>> cap is really only a dust cap
>
>
> I filled the system with R-12 so it can not be a problem. And I plan
> to get a manifold set before soon.
>
> I did not put a tire valve, it just looks like one. I found a proper
> valve in the a/c shop. But it is still leaking.
>
> And can condenser leak be repaired?

If it is a copper condenser it could be soldered, but not an aluminium one. 
in general over here, no-one would bother to try.

Nedavno Yvan napisa:

> And I plan to get a manifold set soon.

And it arrived today.

Car was in the garage, ambient temperature 30 deg Celsius (86F). I
connected the manifold set, and static pressure was 5.4 bar (78psi).

I switched a/c on, and it started 1.8 bar (26 psi) low side, and 9 bar
(130psi) high side. Few minutes later it was 2.2 bar (32psi) low side,
and 11 bar (160psi) high side.

BMW factory service manual states I should test pressures at 2000rpm,
and at that rpm it was 1.7 bar (25psi) low side, and 12.5 bar (180psi)
high side.

I than looked at the sight-glass, and there were some bubbles. So I
connected my R-12 bottle and added freon until I reached 2.2 bar
(32psi) low side, and 17 bar (245psi) high side (at 2000 rpm).

Service manual has a graph, and for 30 deg Celsius (86F) ambient
temperature low side should be 1-2 bar (14.5-29 psi), high side 17-20bar
(245-290psi), and temperature out of center nozzle 4.5-8 Celsius
(40-46F)

So I was near these pressure tolerances, but temperature was ~15C (59F).

Here are some results:

Engine rpm 2000 (as per factory service manual)
Recirculation ON, car in the shade, windows closed

Fan set at 4 (max):
Low side 2.3 bar (33psi), hi side 19bar (275psi), temp 15.5C (60F)

Fan set at 1 (low):
Low side 2.2 bar (32psi), hi side 17bar (246psi), temp 13.5C (56F)
------------------------

at idle

Fan set at 4 (max):
Low side 3.2 bar (46psi), hi side 15.5bar (225psi), temp 15C (59F)

Fan set at 1 (low):
Low side 3.0 bar (44psi), hi side 14.5bar (210psi), temp 13C (55F)

After I switched a/c off hi side was constant at 9.5bar (138psi) and
low went slowly from 5bar (73psi) up to the same as high side.

I than disconnected manifold set, and drove for a while. Temperature
was 12C (54F) minimal with fan on 2. Not low enough.

I did not have appropriate thermometer to measure the temperature at
center nozzle, so i measured at the footwell nozzle.

Any ideas what is wrong, why can't I get low enough temperatures?





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On Fri, 01 Aug 2008 18:21:53 +0100, Yvan  wrote:

> Nedavno Yvan napisa:
>
>> And I plan to get a manifold set soon.
>
> And it arrived today.
>
> Car was in the garage, ambient temperature 30 deg Celsius (86F). I
> connected the manifold set, and static pressure was 5.4 bar (78psi).
>
> I switched a/c on, and it started 1.8 bar (26 psi) low side, and 9 bar
> (130psi) high side. Few minutes later it was 2.2 bar (32psi) low side,
> and 11 bar (160psi) high side.
>
> BMW factory service manual states I should test pressures at 2000rpm,
> and at that rpm it was 1.7 bar (25psi) low side, and 12.5 bar (180psi)
> high side.
>
> I than looked at the sight-glass, and there were some bubbles. So I
> connected my R-12 bottle and added freon until I reached 2.2 bar
> (32psi) low side, and 17 bar (245psi) high side (at 2000 rpm).
>
> Service manual has a graph, and for 30 deg Celsius (86F) ambient
> temperature low side should be 1-2 bar (14.5-29 psi), high side 17-20bar
> (245-290psi), and temperature out of center nozzle 4.5-8 Celsius
> (40-46F)
>
> So I was near these pressure tolerances, but temperature was ~15C (59F).
>
> Here are some results:
>
> Engine rpm 2000 (as per factory service manual)
> Recirculation ON, car in the shade, windows closed
>
> Fan set at 4 (max):
> Low side 2.3 bar (33psi), hi side 19bar (275psi), temp 15.5C (60F)
>
> Fan set at 1 (low):
> Low side 2.2 bar (32psi), hi side 17bar (246psi), temp 13.5C (56F)
> ------------------------
>
> at idle
>
> Fan set at 4 (max):
> Low side 3.2 bar (46psi), hi side 15.5bar (225psi), temp 15C (59F)
>
> Fan set at 1 (low):
> Low side 3.0 bar (44psi), hi side 14.5bar (210psi), temp 13C (55F)
>
> After I switched a/c off hi side was constant at 9.5bar (138psi) and
> low went slowly from 5bar (73psi) up to the same as high side.
>
> I than disconnected manifold set, and drove for a while. Temperature
> was 12C (54F) minimal with fan on 2. Not low enough.
>
> I did not have appropriate thermometer to measure the temperature at
> center nozzle, so i measured at the footwell nozzle.
>
> Any ideas what is wrong, why can't I get low enough temperatures?
>
>
>
>
>


What's the condensor temperature? I'd suspect the evaporator but it's  
worth a look a t the condensor airflow.

Yvan wrote:
> Nedavno Yvan napisa:
>
>> And I plan to get a manifold set soon.
>
> And it arrived today.
>
> Car was in the garage, ambient temperature 30 deg Celsius (86F). I
> connected the manifold set, and static pressure was 5.4 bar (78psi).
>
> I switched a/c on, and it started 1.8 bar (26 psi) low side, and 9 bar
> (130psi) high side. Few minutes later it was 2.2 bar (32psi) low side,
> and 11 bar (160psi) high side.
>
> BMW factory service manual states I should test pressures at 2000rpm,
> and at that rpm it was 1.7 bar (25psi) low side, and 12.5 bar (180psi)
> high side.
>
> I than looked at the sight-glass, and there were some bubbles. So I
> connected my R-12 bottle and added freon until I reached 2.2 bar
> (32psi) low side, and 17 bar (245psi) high side (at 2000 rpm).
>
> Service manual has a graph, and for 30 deg Celsius (86F) ambient
> temperature low side should be 1-2 bar (14.5-29 psi), high side
> 17-20bar (245-290psi), and temperature out of center nozzle 4.5-8
> Celsius (40-46F)
>
> So I was near these pressure tolerances, but temperature was ~15C
> (59F).
>
> Here are some results:
>
> Engine rpm 2000 (as per factory service manual)
> Recirculation ON, car in the shade, windows closed
>
> Fan set at 4 (max):
> Low side 2.3 bar (33psi), hi side 19bar (275psi), temp 15.5C (60F)
>
> Fan set at 1 (low):
> Low side 2.2 bar (32psi), hi side 17bar (246psi), temp 13.5C (56F)
> ------------------------
>
> at idle
>
> Fan set at 4 (max):
> Low side 3.2 bar (46psi), hi side 15.5bar (225psi), temp 15C (59F)
>
> Fan set at 1 (low):
> Low side 3.0 bar (44psi), hi side 14.5bar (210psi), temp 13C (55F)
>
> After I switched a/c off hi side was constant at 9.5bar (138psi) and
> low went slowly from 5bar (73psi) up to the same as high side.
>
> I than disconnected manifold set, and drove for a while. Temperature
> was 12C (54F) minimal with fan on 2. Not low enough.
>
> I did not have appropriate thermometer to measure the temperature at
> center nozzle, so i measured at the footwell nozzle.
>
> Any ideas what is wrong, why can't I get low enough temperatures?

The gas pressure of the pure refrigerant directly correlates to its 
temperature, so at 30 degrees (after being left to stand) you should see 
about 95 psi.

if there is any air in the system you can mess about indefinitely, but try 
bleeding off (slowly ) a little gas, if you aim for just under 30 psi at 
2000 you should have the evaporator at just under freezing point.  If you 
still can't get cold enough air out of the vents then there must still be 
some air in the system.

Nedavno Duncan Wood napisa:

> What's the condensor temperature? I'd suspect the evaporator but
> it's worth a look a t the condensor airflow.


I do not know, I do not have contact thermometer, but it's hot to
touch. What do you think is wrong with the evaporator?


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Nedavno Mrcheerful napisa:

> The gas pressure of the pure refrigerant directly correlates to its 
> temperature, so at 30 degrees (after being left to stand) you should
> see about 95 psi.


We are talking here about static pressure?


> if there is any air in the system you can mess about indefinitely,
> but try bleeding off (slowly ) a little gas, if you aim for just
> under 30 psi at 2000 you should have the evaporator at just under
> freezing point.  If you still can't get cold enough air out of the
> vents then there must still be some air in the system. 


Before I added R-12 I had 25 psi at 2000 rpm, but only 180 psi at high
side. And outlet temperature was ~15C (60F).

What does the air do?


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Yvan wrote:
> Nedavno Mrcheerful napisa:
>
>> The gas pressure of the pure refrigerant directly correlates to its
>> temperature, so at 30 degrees (after being left to stand) you should
>> see about 95 psi.
>
>
> We are talking here about static pressure?
>
>
>> if there is any air in the system you can mess about indefinitely,
>> but try bleeding off (slowly ) a little gas, if you aim for just
>> under 30 psi at 2000 you should have the evaporator at just under
>> freezing point.  If you still can't get cold enough air out of the
>> vents then there must still be some air in the system.
>
>
> Before I added R-12 I had 25 psi at 2000 rpm, but only 180 psi at high
> side. And outlet temperature was ~15C (60F).
>
> What does the air do?

You need the expansion from very high pressure to low in order to effect a 
temperature drop.  So if it isn't squashed enough in the first place (low 
gas quantity) it can't burst out of the restrictor and expand thereby 
drawing in heat.  If there is so much (excess gas) gas in there that the low 
side pressure restricts the gas coming through the (expansion valve) 
restrictor then the gas can't drop to such a low temperature and take away 
so much heat (hence the warmer temperature that you have)  Hence why I said 
to bleed a little refrigerant off to lower the temperature at the 
evaporator.

The static pressure in the system will always be the same (related to 
ambient temperature), even if there is only a small amount of gas in there. 
If you check the bottle pressure you will see what I mean.

If there is any air in there, the system cannot work correctly since air 
does not have the right characteristics of a refrigerant, particularly since 
it has water vapour in it.

If the system has not been vacuumed out for an hour or so before adding 
refrigerant then there is little chance of it working right.

Mrcheerful

Nedavno Mrcheerful napisa:

> If the system has not been vacuumed out for an hour or so before
> adding refrigerant then there is little chance of it working right.



OK. So I'll evacuate the system, take the evaporator out, see if it
needs cleaning, flush the system, drain the oil from the compressor,
change the dryer, vacuum it out, fill it with correct amount of
R-12 (975 gr), and check again.

Do you think that compressor is OK judging by the pressures? I can her
slight humming when it engages. How difficult is to change bearing
(someone told me that it has only one bearing). Can it be done without
disturbing pistons where refrigerant is? Do I need some special tools?

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Yvan wrote:
> Nedavno Mrcheerful napisa:
>
>> If the system has not been vacuumed out for an hour or so before
>> adding refrigerant then there is little chance of it working right.
>
>
>
> OK. So I'll evacuate the system, take the evaporator out, see if it
> needs cleaning, flush the system, drain the oil from the compressor,
> change the dryer, vacuum it out, fill it with correct amount of
> R-12 (975 gr), and check again.
>
> Do you think that compressor is OK judging by the pressures? I can her
> slight humming when it engages. How difficult is to change bearing
> (someone told me that it has only one bearing). Can it be done without
> disturbing pistons where refrigerant is? Do I need some special tools?

Don't forget to add the right amount of the right oil.

The pressure sound fine.  The bearings can usually be changed from the end, 
I don't have any particular knowledge of changing bearings since it would be 
normal (over here) just to replace the compressor complete, but you do need 
a special clutch extractor and a special bearing puller.  The compressor 
will make some noise in any case.

Nedavno Mrcheerful napisa:

> Don't forget to add the right amount of the right oil.


I bought 1 liter of a/c mineral oil. I'll ad some UV die too.


> The pressure sound fine.  The bearings can usually be changed from
> the end, I don't have any particular knowledge of changing bearings
> since it would be normal (over here) just to replace the compressor
> complete, but you do need a special clutch extractor and a special
> bearing puller.  The compressor will make some noise in any case.


a/c shop told me that they can change bearing for £40, compressors are
expensive. Thanks for your help.



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On Sat, 02 Aug 2008 06:00:08 +0100, Yvan  wrote:

> Nedavno Duncan Wood napisa:
>
>> What's the condensor temperature? I'd suspect the evaporator but
>> it's worth a look a t the condensor airflow.
>
>
> I do not know, I do not have contact thermometer, but it's hot to
> touch. What do you think is wrong with the evaporator?
>
>


Well if you've got the right quantity of coolant in there aren't many  
options. As originally pointed out I doubt the system was vacuumed all the  
way down & the gas put in, but if it was then you've got a flow  
restriction somewhere.

On Sat, 2 Aug 2008 13:00:59 +0200, Yvan wrote:

>OK. So I'll evacuate the system, take the evaporator out, see if it
>needs cleaning, flush the system, drain the oil from the compressor,
>change the dryer, vacuum it out, fill it with correct amount of
>R-12 (975 gr), and check again.

Don't forget you need the correct amount of oil as well.

>Do you think that compressor is OK judging by the pressures? I can her
>slight humming when it engages. How difficult is to change bearing
>(someone told me that it has only one bearing). Can it be done without
>disturbing pistons where refrigerant is? Do I need some special tools?

Did you get the extra fans to cool the condenser? Should the car have
the extra fans? Mine has one fan when it doesn't have air conditioning
and three if a/c is fitted. If it needs them and they aren't there it
won't be taking the heat away from the condenser so the evaporator
won't be getting as cool as it should.

-- 
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The from address exists but is mostly dumped,
please send any emails to the address below
e-mail	ngpsm4 (at) infohitsystems (dot) ltd (dot) uk

Nedavno rp napisa:

> Don't forget you need the correct amount of oil as well.

I won't.


> Did you get the extra fans to cool the condenser? Should the car have
> the extra fans? Mine has one fan when it doesn't have air conditioning
> and three if a/c is fitted. If it needs them and they aren't there it
> won't be taking the heat away from the condenser so the evaporator
> won't be getting as cool as it should.


Yes I fitted the two speed auxiliary fan. Without a/c I only had one,
engine driven fan. Now when I turn a/c on, aux fan starts at low.


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On Sat, 2 Aug 2008 23:07:24 +0200, Yvan wrote:

>Yes I fitted the two speed auxiliary fan. Without a/c I only had one,
>engine driven fan. Now when I turn a/c on, aux fan starts at low.

Could that be the problem? I doubt it can shift much heat at low speed.

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Nedavno rp napisa:

> >Yes I fitted the two speed auxiliary fan. Without a/c I only had one,
> >engine driven fan. Now when I turn a/c on, aux fan starts at low.
> 
> Could that be the problem? I doubt it can shift much heat at low
> speed.


No. It should do exactly that. High speed is activated wit the sensor
located in radiator (actually there art both low and high speed
sensors in the radiator).




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Nedavno Duncan Wood napisa:

> What do you think is wrong with the evaporator?
> >
> >  
> 
> 
> Well if you've got the right quantity of coolant in there aren't
> many options. As originally pointed out I doubt the system was
> vacuumed all the way down & the gas put in, but if it was then you've
> got a flow restriction somewhere.


I've done some more tests today.

First, I've sprayed some refrigerant at the temperature sensor of the
ice preventing switch, and it turned the compressor off. So it is not
broken.

Then I removed trim panel at the side of the evaporator where the
expansion valve is, set fan to low, and almost closed all vents to
minimize airflow around the evaporator. Waited about five minutes, but
no sign of icing at the pipes that are visible at the side of the
evaporator.

I know that I might have overcharged the system, I'll try again after
bleeding some refrigerant out, when I find some spare time.


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On Sun, 3 Aug 2008 07:28:42 +0200, Yvan wrote:

>No. It should do exactly that. High speed is activated wit the sensor
>located in radiator (actually there art both low and high speed
>sensors in the radiator).

I can understand that for the engine coolant temperature but I can't
see how it can be expected to cool the a/c system on low. It needs a
lot more air for the a/c than for the engine cooling, at least it does
on my car, but that's R134a although regardless of refrigerant it still
has to get rid of the same amount of heat.

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Yvan wrote:
> Nedavno Duncan Wood napisa:
>
>> What do you think is wrong with the evaporator?
>>>
>>>
>>
>>
>> Well if you've got the right quantity of coolant in there aren't
>> many options. As originally pointed out I doubt the system was
>> vacuumed all the way down & the gas put in, but if it was then you've
>> got a flow restriction somewhere.
>
>
> I've done some more tests today.
>
> First, I've sprayed some refrigerant at the temperature sensor of the
> ice preventing switch, and it turned the compressor off. So it is not
> broken.
>
> Then I removed trim panel at the side of the evaporator where the
> expansion valve is, set fan to low, and almost closed all vents to
> minimize airflow around the evaporator. Waited about five minutes, but
> no sign of icing at the pipes that are visible at the side of the
> evaporator.
>
> I know that I might have overcharged the system, I'll try again after
> bleeding some refrigerant out, when I find some spare time.

I have often found that a little esperimentation with the pressure while 
watching the evap unit is a good way to get things as cool as possible, you 
don't actually want it to be icing, so if you get to that stage just add a 
whiff of gas to bring it above icing and it will be fine, till it loses some 
gas and starts icing, then you know to top it up again.

Mrcheerful

Nedavno rp napisa:

> I can understand that for the engine coolant temperature but I can't
> see how it can be expected to cool the a/c system on low. It needs a
> lot more air for the a/c than for the engine cooling, at least it does
> on my car, but that's R134a although regardless of refrigerant it
> still has to get rid of the same amount of heat.


It blows a lot of air on low too. When it gets on high it makes a lot
of noise, and it blows a looot of air. I've been watching some US
newsgroups, and I remember reading that with a/c on, and in a slow
traffic fan almost newer switches on high.


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Nedavno Mrcheerful napisa:

> I have often found that a little esperimentation with the pressure
> while watching the evap unit is a good way to get things as cool as
> possible, you don't actually want it to be icing, so if you get to
> that stage just add a whiff of gas to bring it above icing and it
> will be fine, till it loses some gas and starts icing, then you know
> to top it up again.


Any ideas on how to bleed some refrigerant, and not oil with it? I
tried before, and first only refrigerant comes out, but than oil comes
out too.




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Yvan wrote:
> Nedavno Mrcheerful napisa:
>
>> I have often found that a little esperimentation with the pressure
>> while watching the evap unit is a good way to get things as cool as
>> possible, you don't actually want it to be icing, so if you get to
>> that stage just add a whiff of gas to bring it above icing and it
>> will be fine, till it loses some gas and starts icing, then you know
>> to top it up again.
>
>
> Any ideas on how to bleed some refrigerant, and not oil with it? I
> tried before, and first only refrigerant comes out, but than oil comes
> out too.

let it settle for an hour or two or overnight, then SLOWLY let a little gas 
out, the oil should stay in.  while the system is running the oil is being 
blown around with the gas, but when stopped it should stay on the pipework, 
slow gas flow should leave it there.

Nedavno Mrcheerful napisa:

> >> I have often found that a little esperimentation with the pressure
> >> while watching the evap unit is a good way to get things as cool as
> >> possible, you don't actually want it to be icing, so if you get to
> >> that stage just add a whiff of gas to bring it above icing and it
> >> will be fine, till it loses some gas and starts icing, then you
> >> know to top it up again.


I tried this, and I just could not get it to blow below 12 C with the
fan speed set to low. If I set it to high, it blows ~16 C. Car was in
the garage hole day, ambient temperature was 32 C, engine rpm 2000,
recirculation on.





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Yvan wrote:
> Nedavno Mrcheerful napisa:
>
>>>> I have often found that a little esperimentation with the pressure
>>>> while watching the evap unit is a good way to get things as cool as
>>>> possible, you don't actually want it to be icing, so if you get to
>>>> that stage just add a whiff of gas to bring it above icing and it
>>>> will be fine, till it loses some gas and starts icing, then you
>>>> know to top it up again.
>
>
> I tried this, and I just could not get it to blow below 12 C with the
> fan speed set to low. If I set it to high, it blows ~16 C. Car was in
> the garage hole day, ambient temperature was 32 C, engine rpm 2000,
> recirculation on.

The best bet is to go to square one:  empty the system, vacuum it for as 
long as you can, 4 hours is the recommended time, purge the charging hoses 
of air and fill the system with the right weight of gas.

On Mon, 04 Aug 2008 07:34:04 GMT, Mrcheerful wrote:

>The best bet is to go to square one:  empty the system, vacuum it for as 
>long as you can, 4 hours is the recommended time, purge the charging hoses 
>of air and fill the system with the right weight of gas. 

But fit a new dryer if you didn't last time.
-- 
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The from address exists but is mostly dumped,
please send any emails to the address below
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Nedavno Mrcheerful napisa:

> > Any ideas on how to bleed some refrigerant, and not oil with it? I
> > tried before, and first only refrigerant comes out, but than oil
> > comes out too.  
> 
> let it settle for an hour or two or overnight, then SLOWLY let a
> little gas out, the oil should stay in.  while the system is running
> the oil is being blown around with the gas, but when stopped it
> should stay on the pipework, slow gas flow should leave it there.


I tried this, and it did not work. So I collected the oil in the
bottle, and there was about an inch of oil at the bottom of it.

Strange thing is that when I looked more closely it was like oil and
water in it, just it was oil at the bottom, ~3/4", and something else
at the top ~1/4". It could be UV die, but I am suspecting that a/c shop
might have put in the wrong oil (they did put in r134 in instead of
r12). And there might be some mineral oil in the system. What do you
think? I checked with the UV light and goggles, and stuff at the top
does not glow. What do you think, what is this?

Oh, and another thing. If I shake the bottle bubbles come out of it,
like in the soda, and it looks like it comes out of the top layer.

BTW there were some debris at the evaporator, but nothing major. It
looks to me like it is clean, no dust, or oil, etc. But I cleaned it
anyway.



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     /__/  /    \      ** Registrovani korisnik Linuksa #291606 **
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Yvan wrote:
> Nedavno Mrcheerful napisa:
>
>>> Any ideas on how to bleed some refrigerant, and not oil with it? I
>>> tried before, and first only refrigerant comes out, but than oil
>>> comes out too.
>>
>> let it settle for an hour or two or overnight, then SLOWLY let a
>> little gas out, the oil should stay in.  while the system is running
>> the oil is being blown around with the gas, but when stopped it
>> should stay on the pipework, slow gas flow should leave it there.
>
>
> I tried this, and it did not work. So I collected the oil in the
> bottle, and there was about an inch of oil at the bottom of it.
>
> Strange thing is that when I looked more closely it was like oil and
> water in it, just it was oil at the bottom, ~3/4", and something else
> at the top ~1/4". It could be UV die, but I am suspecting that a/c
> shop might have put in the wrong oil (they did put in r134 in instead
> of r12). And there might be some mineral oil in the system. What do
> you think? I checked with the UV light and goggles, and stuff at the
> top does not glow. What do you think, what is this?
>
> Oh, and another thing. If I shake the bottle bubbles come out of it,
> like in the soda, and it looks like it comes out of the top layer.
>
> BTW there were some debris at the evaporator, but nothing major. It
> looks to me like it is clean, no dust, or oil, etc. But I cleaned it
> anyway.

That sounds more like a leak stop fluid.

I found some spare time to continue work on my a/c, so hire is an
update.

For those that did not follow this thread from the biginning, I fitted
a/c to my '87 BMW 316 from a wrecked car, and I am trying to make it
work properly.

I went to the a/c shop, and they filled the system with wrong
refrigerant (R-134a), so I decided to continue work myself.

I fitted the correct refrigerant (R-12), but I could not get it to blow
lower than ~15 degrees Celsius.

After helpful suggestions from this group, I decided to pull out the
evaporator, and flush the system.

Evaporetot was not dirty (Not too much anyway, air could freely move
trough it), but it seems that the a/c shop poured some oil in that was
not miscible with the mineral oil that was in the system. When it was
out it was like oil on the water.

So I flushed, drained oil from the compressor, poured correct amount of
mineral oil, changed the dryer, vacuumed the system and filled with
R-12 (at the moment I could not find the scale to measure correct
amount of refrigerant, so I filled again until there were no bubbles at
the sightglass.

And it now works!

Well, sort of :-)  At first I thought that nothing changed, it was
blowing ~13 C at idle. But when I drove off, it went down to the 7 C.
Now compressor is cycling (and it didn't before), and I had pleasant 24
degrees inside with 32 C out.

It looks that combination of higher revs than idle (~2000), and more air
cooling condenser is helping.

Anyway I am happy now, thanks to all who helped.




-- 
      ___   ____
     /__/  /    \      ** Registrovani korisnik Linuksa #291606 **
    /  / \/  /\  \     ** Registered Linux user #291606 **
   /__/\____/--\__\    ** http://counter.li.org/ **