Head Gasket Failure

There has been so much written about the reasons for head gasket failures on the MGF, and how to avoid them, etc, that I do not intend to repeat what has already been aired. Instead I will expand on my experience only, and add numerous www links at the bottom of this page to where further information can be found.

The first thing to say is that my car had done 82,000 miles before there was any sign of a problem. I have always made it a habit of checking the coolant and oil levels and condition on a very regular basis, usually every day or so, so there was little chance of something creeping up on me without being seen, unless of course the car suffered catastrophic failure like a burst coolant pipe.

The first sign of anything wrong was in the expansion tank after the car had stood idle for 4 days, the longest it has done so in the 3 years I have had it, so I guess there had been more time for the oil contamination to rise through the system to the surface. Just one small circle of oil film, perhaps 5mm diameter. No sign of mayo in the coolant or oil and no noticeable loss of coolant. In which case, regular use could be very misleading and hide the true situation, so even more careful monitoring was required, since a lot of the time there was not a sign of oil or contamination at all in the coolant.

Over a period of about 6 weeks the evidence of oil in the coolant slowly started to increase, with a slight build-up of oily scum on the insides of the expansion tank but the oil remained clear. To check that this was an on-going condition, I wiped away this build up from the sides of the tank using kitchen-paper. It still was however only a discoloration rather than a heavy sludge. The next option was to get the car to my Dealers and coolant system pressure tested, the expansion cap checked and a block test made. Quote - "All tests showed no sign of head gasket failure". Unfortunately I did not find this much comfort, since the oil had to be coming from somewhere!

So, where was it coming from?

I had not had any recent work done on the engine or coolant system, so there was no likelihood of the signs of oil being residual. The head gasket keeps five different things from each other, and this looked like a high-pressure oil to water failure, which apparently is an unusual one. The only other place I could think of was the water pump, with the seal failing, though this apparently is rare. Usually the pump bearing fails before anything else.


Two months after the initial signs appeared and before all these questions and the meaning of the universe could be answered, there was a rapid deterioration with actual mayo sludge building up rapidly on the inside of the expansion tank, even though there was still nothing in the oil. Now was the time to get the head off. Even if imminent complete failure the gasket was not going to happen, this sludge was going to build up everywhere, blocking the radiator and pipes and quickly lead to overheating.

Click to enlarge Here you can see the oil seals that have failed and broken away from the old gasket.



Click to enlarge You can see how this seal has clearly come loose.



Click to enlarge The infamous plastic head dowels, one of them broken, though I don't know if this happened in situ or failed when it was removed.



Click to enlarge Click to enlarge If you are having anything done to the engine that involves removing of the cam belt, then it is worth considering replacing the water-pump at the same time, obviously dependant upon overall mileage. The cost of a new pump is 47.00 (Feb 2005) and at the most an extra hour of labour ( though he would have to be a slow mechanic ! ) - a fraction of the overall HGF cost, but if the engine has to be stripped down at a later date solely to replace the pump, the cost would be at least 200 - 300. As it turned out, whilst the pump still worked and the seals were okay, the bearings were badly worn and lumpy, tending to jump and stick as it was turned.

Click to enlarge During this repair the alternator belt was found to be quite badly worn - worth checking on now and then. It can be reached behind a mud cover in the rear off-side wheel arch.



Useful links:

www.mgf.ultimatemg.com/hgf_diagnosis.htm Maintenance: diagnosis and prevention of HGF
http://www.mgf.ultimatemg.com/group2/common_problems/hgf_pages/coolant_bleed_procedure.htm More on the coolant bleed procedure. Instructions here if you want to have a go
http://members.aol.com/_ht_a/DVAndrews/kengine.htm The K Series Engine - loads of information on everything you ever wanted to know about the K series
http://www.sandsmuseum.com/cars/elise/thecar/engine/kingk.html Loads of imformation of the Rover K Series engine
http://shame.4mg.com/ Go here if you want to register and add you details to the Hall of Shame listing of HGFs.
http://www.mgfcar.de/hgf/stretch_bolt_trouble.htm HGF and stretched bolts
http://www.mgfcar.de/k_engine/ More engine stuff
http://www.mgfcar.de/library/more.htm MGF Bolt Torque Figures and more
http://auto.howstuffworks.com/engine.htm How car engines work
http://www.mgfcar.de/banxx/hg.html Transalated German page on HGF

Note: If you come across pages in another language and do not understand them, you can always save the URL address, go to the Google search engine, and then to their Translation page and drop the URL into their free translation option