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MG MGF Technical - MG TF OVERHEATING

Hello there, I have a one year old MG TF 160 and have a problem with it overheating when in traffic. The temperature guage would go up very quickly when stuck in town traffic for periods of time.

The first time it happened, I noticed that the coolant levels are low so I took it in and they said there was a pressure problem with the coolant container cap and fixed it. Since then each time I get out of the car, I have checked the coolant levels and it has been fine.

Yesterday I was stuck in some very bad traffic for about 1 hour or so and the temperature was going up and up very quickly. Soon I noticed smoke coming from the back (the guage was above the three fourths mark but below red), so I pulled over and let it cool down.

Once it was cool, I noticed that practically all the coolant was gone. The thing that I didn't understand was there was another MG TF in the same traffic as me and he did not seem to have a problem with the temperature (think it was a TF 135).

Has anyone had this problem before and if so how was it solved ? Also is it bad for me to run it while the coolant levels are so low ? as I fear that if stuck in traffic on the way to MG dealer, the engine might burn out.

Last question is, I understand that sports cars get hot when not driven fast, but how come boxsters, etc were in the same traffic as me and didn't seem to have a problem ?

Any help would be appreciated.

Many thanks
CP
C Pathiwille

CP,

Your TF shouldn't overheat or lose coolant. If you have any form of vehicle recovery I'd get it to your dealer on a trailer. There is clearly a problem and driving it any more could cause HGF (if you haven't already got one) and worse. If you don't have vehicle recovery I'd get on to the dealer and explain the situation asking them to recover the vehicle (at their expense - since the problem you reported wasn't fixed by the coolant cap replacement).

HTH

Dave
Dave Livingstone

Stupid question.

"Have you checked your fuses?"

There are TWO fuse boxes in an F/TF, and there are fuses for the radiator fans in both of them. If the fan isn't coming on in traffic then you will get overheating.

SF
Scarlet Fever

Whatever the cause (e.g. rad fan not working) overheating was the result. Deal with the potential effect of this first then find and fix the cause.

>I noticed that practically all the coolant was gone.

The system now potentially has air in the system and needs bleeding (see http://www.mgf.ultimatemg.com/HGF_pages/coolant_bleed_procedure.htm)

Where did the coolant go? Yes, some in steam, but what about the rest? Any obvious leaks? Have you checked the dipstick for mayonaisse looking gunk?

Until I knew where the coolant had gone and was sure the system had been bled properly I wouldn't drive the car.
Dave Livingstone

>each time I get out of the car, I have checked the coolant levels

This might have caused you problems - NEVER open the water system when the car is hot, the water boils in the head and air gets into the system (because of the radiator position, the system cannot fully bleed itself)

Sounds like you have a fan fault (as well?) is the car leaking coolant now?
Will Munns

Scarlet,
One fuse box is under the bonnet, where's t'other?
Timmeh

The problem of overheating in traffic is a common one and caused by a blown rad fan fuse in the box behind the battery (fuse is indicated on the fuse box lid) preventing the rad fan operating. The fuse should be 15A i think (although handbook mentions 20A) and sometimes the current surge on startup is enough to blow the fuse. In other words the fuse rating or OE quality is marginal. I think in F's it was 10A and they have uprated to 15A for the TF. Mine was replaced in the summer and has been no problem since; coming on/off countless times on tourimng in the heat of europe. Don't worry, just change the fuse and see how you get on.
Ian Walker

This thread was discussed on 01/12/2003

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