Hope Someone can help

The car is a Vauxhall Astra 1.4 16V W reg (2000)
I have had a problem recently with the thermostat making the car run
cold ie wouldnt rise past 80 on the guage, so replaced it along with
the Temperature sensor after advice from a garage and drained/
flushed/refilled with Vauxhall coolant at the same time . Now the
vehicle warms up fine until the needle sits just past the middle of the
guage ie 90c is this right?
Also on a run ie motorway the guage rises slightly past 90 then moves
back down a bit then rises past the mark again is this the right
behaviour?
The cooling fan kicks in if the car is left idling or in traffic and
cycles with 2-3 mins between .
I guess my question is where should the needle be on the temp guage as
im a bit worried its now running too hot! Prior to the old thermostat
going the guage sat just before the middle line.
Could this be an airlock because i filled it up incorrectly as someone
else said might be the case or is this normal?
Should i drain/bleed the system?
And is there a specific way to bleed this car?

Any advice would be gratefully recieved to settle my mind.

Damian

In article ,
    wrote:

> The car is a Vauxhall Astra 1.4 16V W reg (2000)
> I have had a problem recently with the thermostat making the car run
> cold ie wouldnt rise past 80 on the guage, so replaced it along with
> the Temperature sensor after advice from a garage and drained/
> flushed/refilled with Vauxhall coolant at the same time . Now the
> vehicle warms up fine until the needle sits just past the middle of the
> guage ie 90c is this right?
> Also on a run ie motorway the guage rises slightly past 90 then moves
> back down a bit then rises past the mark again is this the right
> behaviour?


Well, the midway point on my SD1 is 100C. ;-)

But all cars will change their running temp according to conditions. BMW
use a gauge that sits exactly half way, but it's not reading the actual
temp. It's driven off the ECU which translates any 'normal' temperature to
exactly mid gauge. If it goes below or above this range the gauge shows it
same as a 'normal' one. But you can go into a test mode where the OBC
shows the actual temp, and it's all over the place. ;-)

-- 
*On the seventh day He brewed beer *

    Dave Plowman        dave@davenoise.co.uk           London SW
                  To e-mail, change noise into sound.

> The car is a Vauxhall Astra 1.4 16V W reg (2000)
> I have had a problem recently with the thermostat making the car run
> cold ie wouldnt rise past 80 on the guage, so replaced it along with
> the Temperature sensor after advice from a garage and drained/
> flushed/refilled with Vauxhall coolant at the same time . Now the
> vehicle warms up fine until the needle sits just past the middle of the
> guage ie 90c is this right?


Assuming you've fitted an 88degC thermostat then that's about right, 
allowing for gauge inaccuracies...



> Also on a run ie motorway the guage rises slightly past 90 then moves
> back down a bit then rises past the mark again is this the right
> behaviour?


Yes, the temperature will fluctuate slightly either side of the thermostat's 
rated temperature.  The fact you notice it shows that your gauge is 
sensitive and responding quickly (unlike many!)



> The cooling fan kicks in if the car is left idling or in traffic and
> cycles with 2-3 mins between .


As long as the fan comes on long before the gauge enters the red, and it 
goes off reasonably soon (about 2 minutes or less at idle, depending on the 
air temperature outside), then I'd say it was working fine.



> I guess my question is where should the needle be on the temp guage as
> im a bit worried its now running too hot! Prior to the old thermostat
> going the guage sat just before the middle line.


The Haynes manual or your friendly Vx dealer should be able to tell you what 
temperature thermostat is needed - hopefully you noted the rating of the one 
you fitted, and the original?



> Could this be an airlock because i filled it up incorrectly as someone
> else said might be the case or is this normal?
> Should i drain/bleed the system?
> And is there a specific way to bleed this car?


Assuming it uses a sealed expansion tank then you can warm the car up to 
normal temperature with the cap off and this, along with gently squeezing 
the rubber hoses, should be enough to get the air out.  Don't forget to have 
the heater control set to "hot" and you only need to have the engine idling. 
Once the fan has cut in/out then replace the cap and take it for a run.

Darren

> Assuming you've fitted an 88degC thermostat then that's about right,
> allowing for gauge inaccuracies...


The Thermostat that i replaced was 92deg C and the new one was the same
rated temperature!


>As long as the fan comes on long before the gauge enters the red, and it
>goes off reasonably soon (about 2 minutes or less at idle, depending on the
>air temperature outside), then I'd say it was working fine.


Should the fan come on after being on the motorway for 15 miles shortly
after slowing down at this time of year?



>Assuming it uses a sealed expansion tank then you can warm the car up to
>normal temperature with the cap off and this, along with gently squeezing
>the rubber hoses, should be enough to get the air out.  Don't forget to have
>the heater control set to "hot" and you only need to have the engine idling.
>Once the fan has cut in/out then replace the cap and take it for a run


Do you think i should drain/refill/bleed to be on the safe side or
leave it for a few weeks?

Damian

> Should the fan come on after being on the motorway for 15 miles shortly
> after slowing down at this time of year?


I don't know.  Maybe somebody with more experience of your particular model 
can help?  92degC seems quite high and IME the fan switch tends to actuate 
at less than 100degC, so with such a small margin it may be normal 
behaviour.


>>Assuming it uses a sealed expansion tank then you can warm the car up to
>>normal temperature with the cap off and this, along with gently squeezing
>>the rubber hoses, should be enough to get the air out.  Don't forget to 
>>have
>>the heater control set to "hot" and you only need to have the engine 
>>idling.
>>Once the fan has cut in/out then replace the cap and take it for a run
>
> Do you think i should drain/refill/bleed to be on the safe side or
> leave it for a few weeks?


If you do decide to, make sure you fill the system slowly, slackening any 
bleed bolts that may be fitted (ala early Rover K-series), or even 
disconnecting the radiator top hose.  Once it is filled idle the engine with 
the cap off until the fan runs.

Darren