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MG MGF Technical - HGF or is it the Block?

In September 2004 the Water Pump failedon my car. The car was toed to a reliable garage, that used to be an official Rover Garage. They replaced the Water Pump, Head Gasket, Skimmed the head, Cam belt, Alternater Belt the works....
I noticed over the next few months a gradual loss of water from the expansion tank and a layer of mayo starting to form. This gradually got worse and 3 weaks ago I took it back to the garage. They had it a week checking it, compression tested it and flushed the system changing the coolant. After a week they finally confirmed it was another HGF.
The gasket was then replaced, the Head was skimmed again, system flushed and new coolant.
Today a week has passed and whilst servicing my car I have noticed no coolant loss, but the cap has mayo on it and the tanks has brown gunge and floating mayo.
Is this HGF again? or is it the Block that needs skimming, even though they told me they have checked and it was fine! Can anyone advise please?
Stu

>>the Head was skimmed again<<

I thought that you could only skim the head once. If it needed it again it was new head time.
David Clelland

I originally thought it could be skimmed only once, but the garage assured me it could be done again.
Stu

It could be that the system flushing has not been done properly. In my experience the flushing has to be done with an oil dissolving agent in the water and run for quite a while if the system has been heavily contaminated with oil.
Jon

Last week when I picked the car up the Service manager told me that the system had been flushed several times with a Forte cleaning agent. It was also pressure tested.
Stu

Stu,
It could possibly be a cracked block, no amount of skimming will rectify this of course. If you skim a block should not a thicker gasket be fitted to alleviate possible overheating, when I worked on big diesels, over 10 litres, we had to do this.
Have they checked the block, or the head, for any cracking, assuming of course they have actually skimmed it as they have said.

Good luck !

Adrian
Adrian Clifford

Both the head and the block have been checked and they say the block is ok. The head has been skimmed twice, which is ok as long as it remains above an alowed measurement.
Stu

That is correct of course providing the tolerances are met.

Adrian
Adrian Clifford

The other thing to check when rebuilding an engine is the height of the cylinder liners: if they are not within tolerance, there is a strong likelihood that the clamping forces on the cylinder head will be unequal, leading to HGF... It is possibly a contributer here, although the mayo *could* simply be what's waiting to be cleared out?
Rob Bell

Today I informed the Garage about brown gunge and floating mayo. They said to bring it back to them, the system needs flushing again, as if it was the norm.
The thing that concearns me is, if this is normal practice to have to return the car after one week, why did they not tell me about this posibility last week.
Thanks for the help guys i'll post how the saga continues!!!
Stu

I guess that the garage should flush & flush untill clear but ... daughters Rover had a second flush after a week at no charge (probably included in original bill).
JohnP

The car was taken back to the garage this week. The system was Flushed several times, with Forte Flush. They discovered whilst flushing, a rubber hose had a small crack in it. The hose was replaced free of charge it looked as if it would be quite pricey to buy.
The only downfall of the day was whilst driving home I noticed smoke bellowing out of the rear of the car, giving the car the James Bond effect. I managed to return to the garage using a combination of roling with the engine off and starting the engine when climbing. Keeping the Temperature gauge on the norm.
The car just needed the air lock removing, thank God!!!
Stu

This thread was discussed between 05/02/2005 and 10/02/2005

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