MGTF once off overheating

[mini1380cc]

Looking for some advice please. I just bought an 04 115 MGTF as i fancied a convertible for the summer. Seeing the prices of the TF i thought why not. Anyway i bought the car after checking the usual stuff and all was well. Then the temp gauge started rising on the way home. At this point i'm in slow moving roadworks traffic with no hard shoulder. So i carry on as gentle as i could with my eyes glued to the temp gauge. As soon as the gauge hit red i heard a small pop noise then the gauge drops back down to normal!! I pull over at the next service station and let it cool down. The header tank is empty so i fill it and leave the cap off, then nurse it home (40 miles). To my surprise it didnt use a drop, the oil is clean. Proper inspection shows no contamination, constant normal temperature with no water usage and the engine pulls as it should.


Am i being overly cautious because of the K-series HGF stories or do i have a genuine problem? I cant get the problem to re-occur. I'm currently driving about with bottles of water in the boot but so far (another 50 miles or so) i havent topped up at all.

Any advice would be appreciated.

Thanks
Mini1380cc

[MGJohn]

Guesswork here but, there's a few clues to go on. Before you got the car, whoever worked on it be it a garage pro or previous owner, left some air in the cooling system ~ easily done as the K series's cooling system is trickey to bleed properly particularly in the MGF/TF because of its mid-engine location. That is very possible as with air trapped in the system, the temperature gauge will do as you describe.

You did the right thing and when you topped it up after allowing it to cool, just maybe either by luck of judgement, you've managed to top up and 'bleed' the cooling system possibly correctly otherwise the gauge needle would rise again.

Stress again, just remote guesswork. Keep an close watch on that gauge until you're confident all is well.

There are numerous instances of so called K-Series HGFs and 'repeats' following pro-servicing or other work on the car. It is not always merely coincidence or, "they all do that mate...".

Be watchful ...
.

[mini1380cc]

Thanks MGjohn. When i filled it with water to get it home i also opened the bleed screw on the radiator and right enough bubbles came through, i kept filling it until the bubbles cleared. I think the popping noise might have been a stuck thermostat as the car had sat for some time prior to me buying it, hence the reason the temp gauge rushed back to normal. Does any of that make sense? I'm about another 100 miles in and still no symptoms of any cooling/gasket issues, the coolant is still that clearish red colour. I'll keep my fingers crossed.

[MG Mark]

All sounds good. Check that the radiator fan comes on when it should, as the fuse has a tendency to blow, which does not help the cause of cool running around town or at slow speed.

MG Mark

[MGJohn]

Yes, that does make sense ... even so, keep a watchful eye on things until you're confident all is well.

Overheating from lack of coolant can seriously damage ANY car engine let alone the cylinder head gasket. Sometimes that damage only shows up later .... so, keep 'em peeled.

Work colleague had his Toyota severely over heat on the way to Gatwick at the start of his holiday.

I recovered that car for him and he needed more than a cylinder head gasket, needed replacement cylinder head assenmbly ....
..

[hearselover]

mini1380cc said:

Thanks MGjohn. When i filled it with water to get it home i also opened the bleed screw on the radiator and right enough bubbles came through, i kept filling it until the bubbles cleared. I think the popping noise might have been a stuck thermostat as the car had sat for some time prior to me buying it, hence the reason the temp gauge rushed back to normal. Does any of that make sense? I'm about another 100 miles in and still no symptoms of any cooling/gasket issues, the coolant is still that clearish red colour. I'll keep my fingers crossed.

Unfortunatley you should not have opened the bleed screw on the radiator as this is not the last bleed point on the car and not the highest so the likleyhood is you have let more air into the system than you got our. Bleed it properly rear jacked up pop bottle with a tight seal on the expansion tank full of OAT coolant at the 50/50 mix and with the heater control on hot but not blowing start at the radiator then the heater matrix then the bleed screw in the engine bay. Do this a few times making sure the pop bottle stays full of coolant and then at least you know its free of air.

Ash

[mini1380cc]

Thanks guys. I'll bleed it again properly this time. Still so far so good.

[MGTECH]

I agree with most of the posts left here.
The MGTFs are a pain in the a** to bleed fully, you really need to go through the full process 2-3 times to get rid of all the air.
The fan fuse is another problem, it blows for no known reason,

I fitted a controllable temp switch on my TF, You can dial in what temp you want the fans to come on, You must fit in a
Flow Restricting Flange instead of the normal thermostat to use this system, but it works beautifully even on the hottest of days or stuck in traffic jams the guage sits nicely just under the half way mark.

Remember to check often for the dreaded mayo on the dipstick or in the water coolant tank/cap..

[Watcher of the skies]

My understanding is that the fan doesn't come on very often so sometimes they stick.
This then causes the fuse to blow when the fan next switches on.
There was a recall to put in a higher rated fuse and it's worth checking that the fan spins freely.

[Watcher of the skies]

Top lurking BTW!