MGF Coolant Leaking - White Smoke From Engine Vent

[srab...@gmail.com]

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

[Pete C]

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

[Pete C]

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.

[srab...@gmail.com]

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

[Pete C]

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. :)

[srab...@gmail.com]

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

[srab...@gmail.com]

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]

srab...@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.

[srab...@gmail.com]

On Jul 31, 5:58 pm, "Pete C" <petc...@lineone.net> wrote:

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

-- Shuaib

[Pete C]

Your welcome. Please let me know how it goes :)
And join the forum I gave link for.......... costs nowt :)

[srab...@gmail.com]

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

[Pete C]

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.

[Don Parker]

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

Don
zor...@sbcglobal.nettt

[srab...@gmail.com]

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

[Pete C]

Thamnks for posting back. Glad all is well now.
BTW, where Is Fisher ? :)

[srab...@gmail.com]

On Aug 11, 4:44 pm, "Pete C" <petc...@lineone.net> wrote:

They're in Sydenham, SE London.

[Pete C]

Thanks :)

[liam donnell]

hi please help. i havent started my mgf 97 for some time i was havingstarter
problems.. it was left out doors for some time, so i tried starting it today
and when the engine ran there was a bad smell and a lot of smoke came out of
the back engine area. when i turned the engine off it was ok but i am very
worried now.
can any one help me on this one
please
text 353876459339
liam_d...@hotmail.com

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