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MG MGF Technical - hot engine

Hi all,
I noticed my mgtf engine go hot very fast and fan is "always" on. Even in cold winter days (2C, today... fan on!). I'm driving carefully at medium speed, without big accelerations.

- cooling pump runs: opening radiator nut: no cooling liquid goes out when engine is off. Colling liquid goes out while engine runs.

- fun is ok: it's off with cold engine. It turn off as soon as engine became hot. When I switch off engine... fan runs for a little, so temp decreases and it switch off!
- cooling system temp (trusting in indicator instrument) doesn't reach middle-scale.. but fan goes on. When I turn off engine... fun decrease temp to 3/8 scale and goes off. I remember fan started to blow when temp achieved and goes over middle-scale indicator (several months ago)

- inspecting expansion tank... liquid went down since 2 or 3 months. In 3 month (about 4000 km) I added about 1 litre of water. I hope no HGF has happened: no white smoke from exaust pipes, no petrol in cooling liquid (inspecting expansion tank), I have to inspect oil status to look for "water in oil" problem.

Have you suggests?

Thanks you all.

Sorry for my poor english.


Hi, have you checked that the radiator is not blocked?Also worth checking if thermostat is operating correctly and condition of the under floor coolant pipes. Cheers, Alan

Hi ajmackew,
thanks for your answer, but...

how to check for radiator blocks?

I would take it to a radaitor speciallist. or remove it and flush it with a hose,loss of coolant, if no sign of HGF, must be either a leak or coolant boiling out of the system IMHO, Cheers Alan

Do you have air conditioning?

Have you checked the coolant pipes under the car for leaks, especially where the steel pipes join the rubber hoses?

I haven't air conditioning.

I have to check pipes, I hope I'll check them in next week-end.


I checked for oil-in-water and water-in-oil.
Oil and water are not mixing, so head gasket -I suppose- has no damage (I've no white smoking from exausts)

Sometimes the waterpump can leak only when the engine is warmed up, so no drips show under the car because the hot water evaporates. This may have let air into the coolant system which might give the symptoms you report.
Have you tried bleeding the coolant system yet? There is a bleed nipple just next to the temperature guage sensor or the sensor itself might be failing. have a look at Dieter's website. Under the left hand index click on 'Kuhlsystem entluften'
He shows where all the bleed points are.
You could also look at 'Coolant refill and bleed' on this site -
They are both excellent sites packed with information and advice.
This is another very good one.
Good luck,

I inspected (opened) B and C holes. I had no opportunity to check A one (bolt cannot be opened, rusty) and D one.. I didn't know it!

B and C are easy, D is not so important, A is more difficult to reach - but the most important one I think!
Try soaking it with "Plus Gas" a brand of 'penetrating and easing oil'. A cheaper alternative is brake fluid but don't let it touch the paintwork or hoses!

This thread was discussed between 25/11/2008 and 01/12/2008

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