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MG MGF Technical - Now Im confused

Hi all,

About 7 weeks ago, steam starting coming from my car when I was driving it so I pulled over and the water tank was bubbling. I left the car to cool and then checked the tank, it was empty. I filled it up with water and checked the oil, some mayonaise (very little) was present.

I took it straight to MGF and had them to look at it. I told them it was a suspected HGF. They took the car, road tested it + pressure tested it and said there was nothing wrong with it apart from a dodgy coolant cap, for which they charged me £50!!

Now I have been driving the car for about 7 weeks and I decided to check my oil and water. Checked the water, slightly under the level so I topped it up. Checked the oil and there was mayonaise on the dip stick (more than before). I am confused on what to do now.

If I take it to MGF they could charge me £50 to tell me theres nothing wrong with it again, and if I leave it surely the HG is going to go.

Can anyone give me some advice on what to do/try/check now ?

Thanks in Advance....

Mike
MikeG

What sort of mileage do you do ??

Long trips ? short trips ??
tony

Hi Mike. It all sounds a bit dodgy to me. If they pressure tested it and no signs of leaking, all very well and good. But if you have water in the oil (mayo) then you need to flush your engin out with engin flush and add new oil. I myself would take it to another garage and have it checked out again. Not a lot of money, about £10. Just make shure that they do it with the car in the air. ( So you can see underneath). If you take your engin bay panel out befor you go it will cost less. Only takes about 15 mins.
Good luck. Paul...
PAUL HINDLE

Cheers Guys,

Tony,

Lots of short trips unfortunately. My mileage isnt that much, bout 8k per year.

Paul,

Sounds dodgy to me too :-) What sort of thing should I check underneath the car ? I have access to ramps so I could check that for free before taking it to a garage. Also, where can I get engine flush from ?

This might be a silly question but, how is the water getting into the oil 'compartment' ?

Thanks again,

Mike
Mike Giffard

Mike,
Condensation forms in the oil galleries and in the sump of a cold engine. A long trip will heat the oil up and evaporate the water. Short trips do not heat the oil sufficiently to do this, so traces of Mayo can sometimes be seen.

Try and use it on longer journeys for a few days, then re-check. If no mayo then I wouldn't go to the hasstle of flushing the oil out (you will have "boiled off" the water).

Coolant caps can cause the boiling over symptoms as loss of pressure in fluid lowers its boiling point and fluid can become superheated and shoot out the cap. I have replaced 2 caps on my F (I won't say how much they cost from Halfords!)

I think that as they have pressure checked the system, the Mayo is an unfortunate (and heart stoppong) coincidence.

Good luck
Paul Lane
Paul Lane

Cheers for the advice Paul,

Yeah gutted about the £50 charge most was for the diagnostics though, and a few quid for the cap.

After reading your comments Im trying to think of the last time I used the car for a run longer than about 4 miles....and I cant! That is bad! :-(

Im going to take it on a good run tommorow and Sunday. Im gonna take it for a spin down the Gower. Hopefully the mayo will go! If not I suppose I will try flushing the oil out ?

The other side of my dilemma is that my warranty runs out in May, so if the HG is going to go. I hope it will do so before then!

I'll let you know what happens.

Cheers Paul,

Mike
Mike Giffard

Is the water level remaining constant Mike? A common fault on older MGFs is failure of the inlet manifold gasket.

The mayo observation is nonetheless worrying. How much are we talking about here? Small specks of the stuff, or the whole of the dip stick covered?

A pressure test may not necessarily be proof positive of the absence of a HGF.

Another test is to check whether there are HC in the coolant- this needs a MOT exhaust emissions probe in the expansion tank- there shouldn't be any, so if detected, suggests that there are products of combustion leaking into the cooling system.

More on http://www.mgf.4mg.com/hgf_diagnosis.htm
Rob Bell

A similar thing happened to me...

I saw traces of mayo on the dipstick, water level was going down...

I got told that the pressure in the system was fine, but I needed a new radiator and hoses as they'd corroded away.

Great, thought I, much cheaper than a HGF.

Not so long after, back in the garage "Your head gasket's gone, mate"

Ar*e. Could be a coincidence, but perhaps this pressure test isn't a fool-proof check of impending doom...
Pete Slinn

Its the short trips that are causing the mayo in the oil and nothing to worry about!

I would however consider more frequent oil changes as condensation build up in the oil is not good for keeping the gallerys and smaller oil tubes clear

As for the overheat - as its been tested I would imagine all is ok and that the pressure cap was the culprit - I see in demon tweeks catalouge there are a number of replacement header tanks with "more substancial" pressure caps - any thoughts guys on using one of these as a replacement and discarding forever the cheap and failure prone MGF one??????

As for the warranty - you can renew that ! - Well worth the money if you ask me - BUT check it covers the Head gasket and what it would cover on labour charges! Some do not cover gaskets!! Remember worst case senario of a HGF is around £3500 !!

Lastly - to warm an engine enough to burn off condensation you would need to run the car for about 20 minutes at least - oil takes that long to get to temperature - regardless of what the temp gauge is telling you !

So get the extended warranty - forget the cooling system and wait for the Sunshine :) Happy motoring!

tony

Cheers for the replies guys I appreciate the help.

Rob,

When I forst took it to MGF there was specs down the bottom of the stick, but when I checked last week there were a lot more specs and they were going up the stick about 6 inches maybe ? I took it out for a longish run on Sunday, about 40 - 50 miles. When I checked the oil Monday there was quite a bit less specs ie not as much as before I had taken it for a run.

Tony,

Im thinking of changing the oil this weekend or next weekend. Motorplan warranty who Im with now, cover a HGF but I can only claim up to £1000 and Ive already claimed £130!!! Im going to look into which company to renew with Ive seen a few warranty posts recently.

Which oil should I get then guys ? '96 1.8i ? Should I change the oil filter as well ?
Also, Ive got access to a friends garage when changing the oil so I will be able to view the whole underneath of the car, what do you recommend I check ??

Cheers again,

Mike
Mike

Hmm, from your description Mike, I can't be completely sure whether this is the condensation-linked problem Tony refered to, or something more serious.

Seeing as an oil change is a darn-sight cheaper than needlessly stripping the engine down, this seems to be a sensible precaution and first step (are you reasoning that if all traces of the mayo disappear, and stay away, that the problem was condensation after all?).

If changing the oil, it is a false economy not to change the filter as well.

Go for a recommended oil: 0W/40W mobil One is the one I have in the boot at present, although I've used Castrol Magnatec in the past - seems a decent enough oil.
Rob Bell

Mike,
Check all the water hoses, rubber,and metal, especially around the clamped union areas. Then check the usual; corroded brake lines, tie rod ends, CV joint and steering gators, shocks for leakage, brake pads ect.
An oil change on the F is easy, the drain plug and filter are right next to each other, and you can drain both similtaneously. Be careful when adding the oil, it will only take a tablespoon at a time, otherwise you'll overflow the filler.
If you remove the engine cover you can add it directly to the cam cover filler without a real spill. Have fun.
george

If you chose to fill thru the top up cap then remove the dipstick and bung the dipstick hole with some paper.
And make sure that you fill the oil filter with oil before you put it back on as this is kinder to your engine (oil straight away)

Will
Will Munns

Rob,

Yeah Im hoping that by changing the oil, the mayo will never come back :-) Dunno whether this realistic or not, suppose I'll find out after a couple of weeks of motoring ??

Cheers for the advice guys, think I'll go for the Mobil 1 oil and I'll be checking everything George has mentioned when I can see the underside of the car.

Thanks again - I'll let you know how I get on.

Mike
Mike

>>0W/40W mobil One is the one I have in the boot at present

Rob, I thought you should put the oil in the engine :-)

Paul
P9 VLS

Paul

LOL :o)
Rob Bell

With any car with previous owners there is often no way of confirming if the car has suffered from the problem before and if so when. If a recent problem prior to your ownership then it is quite possible that the 'repair' was done and perhaps oil was not changed or that it was drained during the job. The consequence of this is that you will be left with residue from the previous failure and that if the current oil change is done it should remove any previous residues.

Another issue and one especially valid when short journeys are involved is the condensation build up inside the crankcase. This really places the oil in a very difficult position and only the very good synthetics have a good resistance to the formation of the emulsification. Cheaper mineral oils have a very poor response to this build up.

If after the oil and filter change, and for good measure a good 50 mile run to not only get the engine to temp, but keep it working at this level for a reasonable time, the problem creeps back then this is a time to look at a very much deeper investigation.

Rog
Roger Parker

This thread was discussed between 08/03/2002 and 13/03/2002

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