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MG MGF Technical - Minimal coolant loss

If the expansion tank is filled to the halfway crease, I lose about 1cm of coolant every 100 miles or so. I have checked that all the coolant connections are tight and I think the cap is ok.
Any suggestions as to where I might look as to where the coolant could be disappearing.The F is 1996 and has done 82500 miles. HG was replaced at 50000
James Forbes Simpson

Common:
Cap faulty - £5
Rad pinhole weep - ? see a radiator man £60?
hose clips ?
Inlet manifold gasket (should be green, there is a slight cutout above each end stud alowing you to see) if black they perish, should have been changed for green at HGF

Early HGF, signs like front of engine wet at alt end, coolant on alternator- if so then "me too", HG done two years ago, now 90k miles - weeping.
Will Munns

mines doing the same, had it pressure tested at the dealers last week, and no fault found, goes back again on thursday and I'm not taking it back until this and 2 other faults are sorted
Colin Ashworth

I have a two year old stepspeed that has been losing two litres of coolant over 2000 miles. Seems worse when doing short journeys. Been back to the garage on three occassions and each time they have done a pressure test which shows no fault. The dealer admits the car is losing coolant but won't do anything as they cannot see a cause.
JC THACKRAY

You can get them to put flurecent dye in the water, then after you have lost some to revisit with a UV lamp shows the water paths (even if they have dried)
Will Munns

Thanks for the info.It will have to wait for three months before I get a chance to look at it.The car is going into semi-layup whilst I am in the West Indies working.
As far as the local MGR dealer is concerned there is nothing wrong and coolant loss should be expected for the age and mileage of the car!!!
James Forbes Simpson

Also, check the radiator bleed screw.

Open front bonnet, find rectangular opening to the right of the slam panel, the bleed screw is visable through here.

Screw is plastic and has a rubber washer to provide a seal. Over zealous tightening of the screw (by a mechanic) can cause the head to partially shear from the thread resulting in minimal pressure on the wsasher and a slight coolant leak.

SF
Scarlet Fever

had mine pressure tested for the second time, still no problem found, other than replacing the cap, any other ideas where coolant might be dissappearing to that wont show up in a pressure test?
Colin Ashworth

Sounds like this is a fairly common problem. My 97 1.8i has now covered just over 100,000 miles and it too looses some of its coolant (I guess about 1 litre every 1000 miles).

Having read some of the comments on this thread I will be keeping a close eye on the coolant level, especially as it is being serviced this weekend (which will include having the coolant changed).
R Longmore

I have a 96 'F'1.8i 51k serviced at dealers (original service book full) started to loose coolant, couldn't understand why until one fateful day when I checked the oil which looked like a cross between sticky tofee and bisto.......HG was duly replaced at dealers last month. Now paranoid about coolant levels, I checked a couple of days later and zoink, I could see just a small puddle in the bottom of the tank. I filled it back up and invested in a new cap. So far Its all still in there but when going into the boot after a reasonable length trip there always seems to be a steamy aroma coming from the engine compartment (more paranoia i hope)I am just resigned to the fact that a regime of continual checking is the only way to keep the mind demons at bay.............or could it be that continually undoing the cap effects the...............
Simon C.

Sorry Simom but you should have returned the car to the dealer immediately after finding the considerable loss of coolant. With the present system of pressurised engine cooling the only measurable losses should only be due to leaks caused by radiator damage/hose connections/corrosion.Wise after the event I know,but never top up the cooling system above a small amount without finding out out why!
Take it back to the dealer,now!!
J. adams

all well and good, but my dealer tells me he cant find anything wrong. its been pressure tested 3 times and no identifiable problems

praps its the engine gremlins drinking the water?
Colin Ashworth

Been losing a little coolant all summer. Had it pressure tested at beginning of May. It passed but the expansion tank cap failed, so that was replaced. Coolant loss continued. Suspected a hose or clip so replaced a few clips to no avail. Anyway, put it into the garage before warranty is up in March and guess what? Failed pressure test and HGF. Going to check pressure over night again just to make sure everything is OK before I get it back tomorrow.

Believe it or not I'm quite happy that they found where the water was going and fingers crossed it's OK now. Just for the record it's a 2001 Steptronic with just over 25k on the clock.
David Clelland

David,

Please visit the Hall Of Shame and fill in your details, there are very few 2001 model year failures, this means yours is particularly important.

>> http://www.shame.4mg.com <<

Cheers
SF
Scarlet Fever

<<there are very few 2001 model year failures>>

Andy,

Just had a phone call to say that same thing had happened to another 2001 car ½ hour ago. You've met the guy a couple of times, but I'll let him come on himself and say who he is.

DC

p.s. I'll visit Hall of Shame tomorrow when I get the car back.
David Clelland

Well, If it had to happen, I am so glad that it did while still under warranty. (Especially as the clutch on my BGT gave up last week!) I was heading up to Stirling when the heater started blowing cold air on my face. A quick glance at the gauges confirmed worst fears, both were in the red. As I was only about 1.5 miles from the nearest (good) MG dealer I was able to get there with a lot of coasting. The red light only came on as I entered the forecourt. I told them I thought I had an HGF, they replied "We've been expecting you" (That bit is a joke!). I called Dave clelland and discovered that his car went into the same garage on the same day for the same problem. Who would have believed it? I've spent the last few weeks defending MGR against all the bad publicity around HGF guess I am going to have egg on my face now!


Cheers

Alan (2001 vvc 31.5k)
alan dunlop

Jeepers - bad news Alan :o( Perhaps I should stop tempting fate with my car too? 8-O
Rob Bell

Alan, Red light? does your warrenty cover a new engine?
Will Munns

>>>> Who would have believed it?

Me. I wish I didn't.
S Laithwaite

Also had a slow loss of coolant about two years ago. Turned out to be a leaking water-pump.
Beat Fischer

Garage confirmed today that the head has gone. It will be done under warranty and I can collect the car Tuesday. I can't complain about that. Quick, efficient, no hassle service with a smile!


Cheers
Alan
Alan Dunlop

Just added my details to the hall of shame. Only four 2001 cars listed. I find this hard to believe since I know of three 2001 cars that have suffered this fate (Stu Gray, Alan Dunlop and myself) Granted Alan may not have added his details yet but I'm pretty sure that Stu did. However, on this basis you've got to question the accuracy of the statistics.
David Clelland

Hi David,

Sorry to hear your news. I guess that your run down to Abingdon earlier this year without water loss was a bit of a red herring then :-(

Have the garage given you any ideas on the cause? In my first HGF I had a slow loss over time. There was a weep from the water pump, which was then replaced, but eventually it became clear that this wasn't the only cause of the water loss and the HGF followed.

As well as the rubber-sealing strip around the outer edge of the gasket, there are three pairs of sealing rings, one pair between each cylinder. On my failed gasket you could see that the ring on the exhaust side between cylinders one and two and also between cylinders three and four had lifted. Intriguingly, the ring between cylinders two and three had not.

When Dave Andrews, respected K series guru, saw the failed gasket he had an explanation. It seems that there are compression bars at each end of the head gasket that stop it being tightened down too much. If the cylinder liners on my engine were all a little low, then the clamping pressure would be different between the middle of the head and the ends – strong in the middle of the head, but weak towards the ends – causing the head to be bow shaped. This could allow combustion gases to escape and blow across the rubber sealing rings between cylinders one and two and between cylinders three and four, until eventually they lifted.

Knowing this didn't lead to any 'solution' to the underlying problem, but it did satisfy my curiosity.

In contrast my second HGF was the classic version with water spurting out of the head above the alternator. Here the rubber strip around the edge of the gasket had lifted, despite this now being an uprated gasket from Mike Satur with the 'pinned through' rubber strip. The strip had just lifted either side of where it had been pinned :-( I also had the metal dowels by now of course, and had made sure that the repair from HGF number one had used new stretch bolts etc. etc.

No underlying cause could ever be concluded for this second HGF other than the possibility of a block face that is not completely flat causing uneven clamping pressure on the gasket around that area. Here again this is Dave Andrew's theory on the 'classic' above the alternator failure. However, again there is no real solution that does not involve massive expenditure. However an additional sealant was applied to the new gasket (this time latest MGR OEM).

So David, it would be interesting to know how your (and Alan's) gasket failed. Maybe it doesn't help us much, but it's fascinating stuff isn't it ;-)
Dave Livingstone

Dave,

I'm afraid that I can't give you any details with regards to where the gasket failed. As you know I've been all over the car looking for a leak, replacing clips and caps without any success. It didn't help that the car was pressure tested at the beginning of the summer and passed. Since the warranty is up next March I decided to put the car into the dealers for further investigation. So, last weekend I whipped the ITG off (didn't want to give them any excuses) and dropped it into the garage on Wednesday morning. Got a phone call on Thursday to say that it had failed a pressure test over night and that they had taken the head off and the gasket was damaged. They didn't say where it was leaking and to be honest I was so pleased that they had found the fault I forgot to ask. Car was pressure tested again on Thursday night and I got it back on Friday and I'm glad to say it seems to be running fine.

Where the water was going is a real mystery to me. The car only tends to get used at weekends so water and oil are checked more or less before each outing. Never been any traces of water in the oil and the car has been performing well, so no drop in compression. I can only think that it has been a very slight leak out the way and it only happens when the engine is cold. Hence, if I'm going a very long run (say down to Abingdon) it only leaks a tiny drop for the first mile or so with no real change in level over the whole journey. Alternatively, if I'm stopping and allowing the engine to cool a few times during a journey then coolant will be lost more often showing a marked difference in level from start to finish.

I'll still be keeping an eye on things over the next few weeks just to make sure that it really is cured. I'll probably keep the ITG off over the winter (car doesn't do a lot of running then) and put it back on in the Spring along with a newly acquired 52mm TB.

DC

p.s. Alan's HGF was a lot more dramatic than mine by all accounts. I'll ask him to get more details when he collects his car on Tuesday.
David Clelland

This thread was discussed between 24/11/2003 and 13/12/2003

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