I would be very grateful if someone could give me some pointers.

My 1998 MGF 1.8 VVC had the head gasket replaced earlier this year
(2008). However a couple of days ago I noticed the following symptoms:

+ After driving for about 40 mins, the temperature gauge rises from a
middle setting (between Hot and Cold) and starts approaching the red
section on the temp dial on the Hot.
+ White smoke starts to emit from the vents above the engine in the
boot area
+ The temperature gauge seems to fluctuate in the hot zone. Seems to
get worse when the car is idle which seems a little odd.
+ When I open the flap in the boot, the coolant expansion tank is
close to FULL but boiling away. Colour is rusty red/green.
+ Coolant seems to have leaked all over the engine as well - which may
explain the smoke
+ There is no appearance of the white "mayonnaise" type substance on
the oil dipstick or elsewhere around the engine/expansion tank which
is symptomatic of HGF
+ Car cools and the above start again.

Many thanks in advance.

-- Shuaib

srabbani@gmail.com wrote:
> I would be very grateful if someone could give me some pointers.
>
> My 1998 MGF 1.8 VVC had the head gasket replaced earlier this year
> (2008). However a couple of days ago I noticed the following symptoms:
>
> + After driving for about 40 mins, the temperature gauge rises from a
> middle setting (between Hot and Cold) and starts approaching the red
> section on the temp dial on the Hot.
> + White smoke starts to emit from the vents above the engine in the
> boot area
> + The temperature gauge seems to fluctuate in the hot zone. Seems to
> get worse when the car is idle which seems a little odd.
> + When I open the flap in the boot, the coolant expansion tank is
> close to FULL but boiling away. Colour is rusty red/green.
> + Coolant seems to have leaked all over the engine as well - which may
> explain the smoke
> + There is no appearance of the white "mayonnaise" type substance on
> the oil dipstick or elsewhere around the engine/expansion tank which
> is symptomatic of HGF
> + Car cools and the above start again.
>
> Many thanks in advance.
>
> -- Shuaib

You need a new cap for the coolant expansion tank. Halfords do them, but be 
SURE it's the right one.......they have a habit of getting it wrong.
It's common fault, so later, get over to ebay and get a couple of spares.
For furure help, go here.....
http://forums.mg-rover.org/forumdisplay.php?f=12
Very friendly and helful bunch.
If you continue to drive with the bad cap, you risk gasket failure again!!!
HTH :)
-- 
Pete C
London UK

Srabbani, I'm concerned you haven't replied. Running your F as it is is a 
no-no!!!
My 'repy to' is valid if you want to mail me.
-- 
Pete C
London UK

Pete, thanks for the advice. Digging a little deeper into the issues
particularly around the temp rising when idle, I found the following
link on the web:

http://www.mgf.ultimatemg.com/group2/common_problems/HGF_pages/related_problems_overheating.htm

Wondering if this is the issue - the symtoms seem to correspond
exactly. Have tested the fuses and both seem intact. Could point to an
issue with
the ECU temp sensor or radiator. Will do some more digging.

-- Shuaib

srabbani@gmail.com wrote:
> Pete, thanks for the advice. Digging a little deeper into the issues
> particularly around the temp rising when idle, I found the following
> link on the web:
>
> http://www.mgf.ultimatemg.com/group2/common_problems/HGF_pages/related_problems_overheating.htm
>
> Wondering if this is the issue - the symtoms seem to correspond
> exactly. Have tested the fuses and both seem intact. Could point to an
> issue with
> the ECU temp sensor or radiator. Will do some more digging.
>
> -- Shuaib

Unlikely.
Coolant cap...............less than a fiver. It's a common and well known 
fault, the symtoms of which you describe exactly.
Go to the link I gave you and ask there. A tenner says you'll get the same 
answer. :)
-- 
Pete C
London UK

Pete

Will certainly look into getting a new coolant cap. In the meantime
can you help me understand why a faulty coolant cap would cause the
engine temp to rise to max and also why it would cause the coolant
itself to boil in the expansion tank.

Regards

Shuaib

Pete C wrote:
> srabbani@gmail.com wrote:
> > Pete, thanks for the advice. Digging a little deeper into the issues
> > particularly around the temp rising when idle, I found the following
> > link on the web:
> >
> > http://www.mgf.ultimatemg.com/group2/common_problems/HGF_pages/related_problems_overheating.htm
> >
> > Wondering if this is the issue - the symtoms seem to correspond
> > exactly. Have tested the fuses and both seem intact. Could point to an
> > issue with
> > the ECU temp sensor or radiator. Will do some more digging.
> >
> > -- Shuaib
>
> Unlikely.
> Coolant cap...............less than a fiver. It's a common and well known
> fault, the symtoms of which you describe exactly.
> Go to the link I gave you and ask there. A tenner says you'll get the same
> answer. :)
> --
> Pete C
> London UK

Pete

Will certainly look into getting a new coolant cap. In the meantime
can you help me understand why a faulty coolant cap would cause the
engine temp to rise to max and also why it would cause the coolant
itself to boil in the expansion tank.

Regards

Shuaib

Pete C wrote:
> srabbani@gmail.com wrote:
> > Pete, thanks for the advice. Digging a little deeper into the issues
> > particularly around the temp rising when idle, I found the following
> > link on the web:
> >
> > http://www.mgf.ultimatemg.com/group2/common_problems/HGF_pages/related_problems_overheating.htm
> >
> > Wondering if this is the issue - the symtoms seem to correspond
> > exactly. Have tested the fuses and both seem intact. Could point to an
> > issue with
> > the ECU temp sensor or radiator. Will do some more digging.
> >
> > -- Shuaib
>
> Unlikely.
> Coolant cap...............less than a fiver. It's a common and well known
> fault, the symtoms of which you describe exactly.
> Go to the link I gave you and ask there. A tenner says you'll get the same
> answer. :)
> --
> Pete C
> London UK

srabbani@gmail.com wrote:
> Pete
>
> Will certainly look into getting a new coolant cap. In the meantime
> can you help me understand why a faulty coolant cap would cause the
> engine temp to rise to max and also why it would cause the coolant
> itself to boil in the expansion tank.
>
> Regards
>
> Shuaib

Temp is rising because the coolant is no longer under pressure and cooling. 
The valve in the cap fails which means coolant boiling at approx 100°C 
instead of around 120°C under pressure.

-- 
Pete C
London UK

On Jul 31, 5:58 pm, "Pete C"  wrote:
> srabb...@gmail.com wrote:
> > Pete
>
> > Will certainly look into getting a new coolant cap. In the meantime
> > can you help me understand why a faulty coolant cap would cause the
> > engine temp to rise to max and also why it would cause the coolant
> > itself to boil in the expansion tank.
>
> > Regards
>
> > Shuaib
>
> Temp is rising because the coolant is no longer under pressure and cooling.
> The valve in the cap fails which means coolant boiling at approx 100°C
> instead of around 120°C under pressure.
>
> --
> Pete C
> London UK

Thanks - will follow your advice this weekend and keep you posted.
Many thanks for the info.

-- Shuaib

srabbani@gmail.com wrote:
> On Jul 31, 5:58 pm, "Pete C"  wrote:
>> srabb...@gmail.com wrote:
>>> Pete
>>
>>> Will certainly look into getting a new coolant cap. In the meantime
>>> can you help me understand why a faulty coolant cap would cause the
>>> engine temp to rise to max and also why it would cause the coolant
>>> itself to boil in the expansion tank.
>>
>>> Regards
>>
>>> Shuaib
>>
>> Temp is rising because the coolant is no longer under pressure and
>> cooling. The valve in the cap fails which means coolant boiling at
>> approx 100°C instead of around 120°C under pressure.
>>
>> --
>> Pete C
>> London UK
>
> Thanks - will follow your advice this weekend and keep you posted.
> Many thanks for the info.
>
> -- Shuaib
Your welcome. Please let me know how it goes :)
And join the forum I gave link for.......... costs nowt :)
-- 
Pete C
London UK

On Jul 31, 9:31 pm, "Pete C"  wrote:
> srabb...@gmail.com wrote:
> > On Jul 31, 5:58 pm, "Pete C"  wrote:
> >> srabb...@gmail.com wrote:
> >>> Pete
>
> >>> Will certainly look into getting a new coolant cap. In the meantime
> >>> can you help me understand why a faulty coolant cap would cause the
> >>> engine temp to rise to max and also why it would cause the coolant
> >>> itself to boil in the expansion tank.
>
> >>> Regards
>
> >>> Shuaib
>
> >> Temp is rising because the coolant is no longer under pressure and
> >> cooling. The valve in the cap fails which means coolant boiling at
> >> approx 100°C instead of around 120°C under pressure.
>
> >> --
> >> Pete C
> >> London UK
>
> > Thanks - will follow your advice this weekend and keep you posted.
> > Many thanks for the info.
>
> > -- Shuaib
>
> Your welcome. Please let me know how it goes :)
> And join the forum I gave link for.......... costs nowt :)
> --
> Pete C
> London UK

Pete - Bought a new coolant cap. Unfortunately, the same symptoms.
When the engine is warm and the car is left idle for about 10 mins,
the temperature starts to rise towards hot.Coolant bubbling.

Assuming there is a radiator fan beneath the front bumper - but even
listening carefully I can hear nothing from this area of the car. Can
I assume the ECU sensor or radiator fan is the culprit?

Looks like I need to take the car to a specialist.  :(

Regards,

-- Shuaib

srabbani@gmail.com wrote:
> On Jul 31, 9:31 pm, "Pete C"  wrote:
>> srabb...@gmail.com wrote:
>>> On Jul 31, 5:58 pm, "Pete C"  wrote:
>>>> srabb...@gmail.com wrote:
>>>>> Pete
>>
>>>>> Will certainly look into getting a new coolant cap. In the
>>>>> meantime can you help me understand why a faulty coolant cap
>>>>> would cause the engine temp to rise to max and also why it would
>>>>> cause the coolant itself to boil in the expansion tank.
>>
>>>>> Regards
>>
>>>>> Shuaib
>>
>>>> Temp is rising because the coolant is no longer under pressure and
>>>> cooling. The valve in the cap fails which means coolant boiling at
>>>> approx 100°C instead of around 120°C under pressure.
>>
>>>> --
>>>> Pete C
>>>> London UK
>>
>>> Thanks - will follow your advice this weekend and keep you posted.
>>> Many thanks for the info.
>>
>>> -- Shuaib
>>
>> Your welcome. Please let me know how it goes :)
>> And join the forum I gave link for.......... costs nowt :)
>> --
>> Pete C
>> London UK
>
> Pete - Bought a new coolant cap. Unfortunately, the same symptoms.
> When the engine is warm and the car is left idle for about 10 mins,
> the temperature starts to rise towards hot.Coolant bubbling.
>
> Assuming there is a radiator fan beneath the front bumper - but even
> listening carefully I can hear nothing from this area of the car. Can
> I assume the ECU sensor or radiator fan is the culprit?
>
> Looks like I need to take the car to a specialist.  :(
>
> Regards,
>
> -- Shuaib

Fuses :
Under bonnet No.2
Under dash, drivers side No.6
Not sure which of these is rad. fan.
Beyond that, I wouldn't like to say.
I'd suggest you ask in
http://forums.mg-rover.org/forumdisplay.php?f=12
They are really very knowledgeable people.
:)
-- 
Pete C
London UK

Hi
    Based on the syptoms my guess is a bad head gasket dumping cylinder 
pressure in to the cooling system.

Don
zordac@sbcglobal.nettt

On Aug 6, 1:58 am, Don Parker  wrote:
> Hi
>     Based on the syptoms my guess is a bad head gasket dumping cylinder
> pressure in to the cooling system.
>
> Don
> zor...@sbcglobal.nettt

Okay an update. Took the MGF to Fisher MG specialists (very helpful by
the way). The ECU temp sensor was faulty (now replaced) and the
connections to the radiator fan were also loose. The car is now A okay
- no more overheating. Thanks for all the feedback - all very
informative.

Regards,

-- Shuaib

srabbani@gmail.com wrote:
> On Aug 6, 1:58 am, Don Parker  wrote:
>> Hi
>> Based on the syptoms my guess is a bad head gasket dumping cylinder
>> pressure in to the cooling system.
>>
>> Don
>> zor...@sbcglobal.nettt
>
> Okay an update. Took the MGF to Fisher MG specialists (very helpful by
> the way). The ECU temp sensor was faulty (now replaced) and the
> connections to the radiator fan were also loose. The car is now A okay
> - no more overheating. Thanks for all the feedback - all very
> informative.
>
> Regards,
>
> -- Shuaib

Thamnks for posting back. Glad all is well now.
BTW, where Is Fisher ? :)
-- 
Pete C
London UK

On Aug 11, 4:44 pm, "Pete C"  wrote:
> srabb...@gmail.com wrote:
> > On Aug 6, 1:58 am, Don Parker  wrote:
> >> Hi
> >> Based on the syptoms my guess is a bad head gasket dumping cylinder
> >> pressure in to the cooling system.
>
> >> Don
> >> zor...@sbcglobal.nettt
>
> > Okay an update. Took the MGF to Fisher MG specialists (very helpful by
> > the way). The ECU temp sensor was faulty (now replaced) and the
> > connections to the radiator fan were also loose. The car is now A okay
> > - no more overheating. Thanks for all the feedback - all very
> > informative.
>
> > Regards,
>
> > -- Shuaib
>
> Thamnks for posting back. Glad all is well now.
> BTW, where Is Fisher ? :)
> --
> Pete C
> London UK

They're in Sydenham, SE London.

srabbani@gmail.com wrote:
> On Aug 11, 4:44 pm, "Pete C"  wrote:
>> srabb...@gmail.com wrote:
>>> On Aug 6, 1:58 am, Don Parker  wrote:
>>>> Hi
>>>> Based on the syptoms my guess is a bad head gasket dumping cylinder
>>>> pressure in to the cooling system.
>>
>>>> Don
>>>> zor...@sbcglobal.nettt
>>
>>> Okay an update. Took the MGF to Fisher MG specialists (very helpful
>>> by the way). The ECU temp sensor was faulty (now replaced) and the
>>> connections to the radiator fan were also loose. The car is now A
>>> okay - no more overheating. Thanks for all the feedback - all very
>>> informative.
>>
>>> Regards,
>>
>>> -- Shuaib
>>
>> Thamnks for posting back. Glad all is well now.
>> BTW, where Is Fisher ? :)
>> --
>> Pete C
>> London UK
>
> They're in Sydenham, SE London.
Thanks :)
-- 
Pete C
London UK