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MG MGF Technical - poorly F

A few days ago i posted a thread on a mystery leak from my F about a third of the way down the car (from the front and pretty central). There were a few suggestions, but i didn't get chance to get under it the weekend and now it has overheated !!!

Does this suggest it was a coolant leak??

Help appreciated.

ps the RAC man is on his way out what are the chances of a temp fix to get me home?

Nik
n stretton

Probably best you check the oil. If it is a little mayonaisey (spelling?) then it could be a dreaded HGF, also check the coolant bootle might have oil in it again evidence of HGF. If it is then no option but to get to a garage!
Sorry!
R Baker

SSSssshhhhhh don't mention that I have all my digits crossed !!
n stretton

If the Head gasket is leaking water under pressure it could be spraying onto the bulkhead and running down on to the floor which would come out under the drivers seat area'ish, but it sounds more likely that it is the front/rear pipes that are leaking if the area is that far forward, hopefully topping up the water may get you to the garage, and HGF avoided.
Mike
Mike

I think I missed that earlier thread Nik?

Yes, chances are that it was a coolant leak.

Perform the usual inspections (water/oil etc), and also see if there is a water leak from under the car.

If you have any tools with you, remove the engine inspection cover, and look around the circumference of the engine for evidence of water leak.

One thing though Nik - was this overheating in slow-moving traffic, and did it sort itself out when the traffic got moving again? In which case the overheating could simply be a sensor fault.

http://www.mgf.ultimatemg.com/hgf_pages/HGF.htm
Rob Bell

Rob I was actually sitting on a car park when it over heated, i was reading the paper and didn't spot the gauge creeping up. Only noticed when the steam started coming out of the back grilles.

The RAC have been out for a look he seemed to think it could have been a dodgy relay meaning the fan didn't come on. Hopefully he is right. He had a look underneath and there were no signs of a leak but there must be something leaking as there is an evergrowing puddle in the garage where i park up overnight. I will try to get it up on ramps tomorrow and have a proper look.

Nik
n stretton

Nik,

When you're looking for leaks, be aware that the underfloor cooling pipes can and do leak in the section that disappears under the skid panel. It's in the sort of area that you originally described. Obviously the fact that they are covered up here makes the leak hard to spot.

I'd be worried about the co-incidence of the coolant leak and overheating. This doesn't make me think of a sensor or fuse problem. What was the level of coolant like in the expansion bottle after the overheat and steam?

Dave

Dave

Dave it was virtually empty. although it didn't take much to fill it back up.

Co incidentally, the RAC man didn't try to folg me a battery ;-)

Nik
n stretton

Nik

The RAC was recently closed on Tuesday morning for staff training and this week they concentrated on not folging batteries :-)
JohnP

Anyone want a battery? ;-)
R H Greig

Nik,

If the expansion bottle was completely empty, you now need to worry about air in the system and maybe should bleed it. If it didn't quite empty and you topped it up, then you should be OK.

Getting back to the leak and the overheat, it seems to me that there's some contradictory evidence in what's happened.

You got steam from the engine bay which implies

a) serious overheat causing the coolant to pressurise sufficiently to blow the the expansion bottle cap

b) a split hose spraying coolant on to the hot engine.

If it was b) then why does your _normal_ leak seem to be nearer the front of your car?

If it was a) then either there would need to be a co-incidental second problem, (like a faulty temperature sensor or radiator fan fuse that caused the overheat at idle) OR you lost so much coolant from your _normal_ leak that the engine seriously overheated.

In the latter case I'd expect your expansion bottle to be completely empty and require significant topping up.

Anyone else got any thoughts?

Maybe it is the battery.

Dave
Dave

Over heat and steam is what I got when the ECU temp sensor failed Dave - which I guess is (a)

The second time I got steam from the expansion tank was when the rad failed (corrosion). This presumably caused the cooling system to depressurise and allow the coolant to boil in the expansion tank.

Nik - sensor failure seems more common than relay faults, so that would be the first thing to investiagate with respect to the overheating.

Then get the coolant pipes and radiator thoroughly inspected. I expect that you'll find that your radiator is leaking.

Best get these things sorted before your head gasket is jeopardised.
Rob Bell

OK thanks for all the assistance folks.

Nik
n stretton

This thread was discussed between 21/01/2003 and 22/01/2003

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