The MGF Register Forums

Hello, I've only just joined this forum, so I may be resurrecting an old chestnut, apologies if so. my car is a late 2003 TF135 manual with 41k on the clock

My issue is, I have a slight coolant loss even when cold and stationary, about quarter-half pint a week. It appears to be around the exhaust manifold toward the N/S as it seems to drip onto the exhaust, with some some running onto the sump. Initially, I suspected the water pump, even though I changed this about 4k miles ago when I changed the cam belt and tensioner as well as replacing the underfloor pipes with S/S.
The take off to the the underfloor pipe on the N/S of the head appears to be quite dry and I haven't found and leaks on any of the pipes either.
Also, there appears to be oil in the header tank, although this could be residue from a suspected and replaced HGF before I bought the car. as there was/is coolant residue on the block. There is no evidence of water in the oil, no mayonnaise on dipstick, or filler caps. The oil was flushed at the time of the cam belt change.
Is it possible that there is a leak between the head & block outwards without affecting the combustion chamber? or are there any core plugs in the block in that area?
Any thoughts or advice would be very welcome
Regards
David

Hi Jackall, another common leak area/weakness could be the inlet manifold gasket. It could be that coolant flow through here is leaking 'the other way' and being burned by the engine instead; then you wouldn't see any residue inside the engine bay...

Common symptoms are usually engine bay hotness and a unique smell where coolant may be being burned off the exhaust. Alternatively, a difficulty with warm starting, the unique burning smell and a misty vapour in the exhaust if coolant is mostly being drawn into the engine (although my leak experience was external.)

Your inlet manifold is aluminium, mine's plastic ('05 TF 115), but these are very oft-neglected items. I replaced mine recently after HG replacement in 2010 by a previous owner - and it must have been the original. When you see how flimsy they are you might not be surprised...

Hope this complements your own investigations...

Rather than guesswork, it might be best to take off the engine access cover and have a good look at ALL the coolant pipes and connections which are in there. If you take it to a garage they'll probably just try and tell you the head gasket has gone (stock answer for the MGF/TF ignorants). The water pump can be a source of coolant loss, as can the inlet manifold, but if it's pooling on the floor it could well be elsewhere.

Hi and welcome to the forum

Pressure testing the coolant system is good for finding leaks.

James

Hello, and thank you all for your considered replies, much appreciated. Yes, the engine cover is off, as is the cover on the O/S under the wheel arch. I've checked all of the pipe work around the exhaust side of the engine (rear of engine looking from the back of the car) there is no evidence of coolant around the inlet manifold, or any of the pipework between engine and bulkhead behind the petrol tank and seats, yet there is some fresh water under the exhaust manifold which drips onto the the exhaust, this has an unusual smell which defies description.

Pressure testing is a very good idea, Is there a more appropriate way other than fitting a bung into the header tank with a pipe to a low (<15psi) pressure pump?

I'm assuming at the moment, that another HGF has not occurred as it probably was repaired at about 28k by main dealer with water pump and cam belt, (I fitted a new water pump, cam belt and tensioner at 37k just after I bought the car as history was then unknown, now at 41k)

Yes, I realise the stock answer from most garages would be along the lines of "Head Gasket gone, very expensive, better to scrap it" NO WAY am I going to do that. It sits nicely alongside our MG3 and much loved Y type!

Thanks again
David

Coolant on the exhaust has a peculiar smell - one I try and avoid!

Leverage from the exhaust manifold, particularly if the anti-torque fittings are "slack/worn", can let coolant out as there are no head studs round the circumference of the block. It sounds like this might be happening.

I would think nothing fatal will happen - firstly check the anti-torque assys top and bottom are good, check the exhaust rubber hangar has not aged and stretched.

It could be something like this, depends on what sort of HG was fitted. The polymer bead type can give your described symptoms if the head is strained by the manifold.

Do a little more investigation, ie look at the head with the engine running (with the lid off!!), rev occasionally to see if any coolant weeps out of the head/block joint above the manifold and take it from there.

Your original diagnosis might well be correct.

Good News (1) MGTF passed it's MoT without any advisories! Good News (2) whilst up on ramp, tester invited me under, could clearly see drips of coolant coming down the block on the gearbox end in the space between the engine and bulkhead from around the exhaust manifold
Bad News Tester suggested that it was leaking out from the head gasket. Next Step: pressure test the system.

Options (1) Try to replace Head Gasket with engine in situ (2) Remove engine & subframe Could at least clean up the sub frame and do any other jobs needed.

Any thoughts would be gratefully received

David

Yes, good to finally know what it is...

IMO I reckon you ought to do the subframe too 'cos HG replacement puts your TF 'right' and levels the see-saw. (While you're there I reckon you ought replace the IM gasket. It's very cheap and easier than sitting in the boot cursing.)

BUT don't we all look forward to slogging away at our steeds to make them even better? Please tell me that's the real reason we graze our knuckles, spend hard-earned money, lay in puddles...