Post
by mail@alaister.co.uk » Sun Jul 29, 2018 10:18 pm
I thought I should relate my recent experience following the purchase of a 2001 MGF 1.8i in Bournemouth. It was in what I considered to be mint condition: 64k miles; all important upgrade work done on the cylinder head; 4 brand new, good spec tyres; and, full MoT. It just needed a polish and a soft top scrub/rear window clean to look perfect, the suspension pumped up and the wheels aligned to handle properly and I purchased it for a very reasonable price. The vendor even arranged to have the water pump and timing belt changed at a cost of £200 plus parts, after the MoT inspection report had an advisory of a coolant leak, which delayed handover for a couple of weeks.
However, after driving the car for quite short distances over a few weeks, the car experienced overheating to the point of suffering an explosive steam expulsion from the engine compartment! After getting it home, I was relieved to find there was a burst coolant hose, so I replaced that in the expectation that would fix the problem. However, when I went to bleed the cooling system, I found the bleed screws on the radiator and heater easy to open, but the one in the engine compartment was completely seized and had obviously not been touched for a very long time.
This made me realise the mechanic who replaced the water pump had not done the job properly, no doubt causing the overheating. I then looked at his invoice, which had been passed to me as part of the car's service history, and was appalled to find this:
'Bled cooling system.'
Then as advisories:
'Bleed screw in engine compartment seized.
Top up coolant when engine cool.'
Which obviously meant the system HADN'T been bled! I couldn't believe a mechanic would return a car to the customer knowing full well the job hadn't been done properly and that a major breakdown could/would result! Why couldn't he have unseized the screw, he is a mechanic after all and this sort of thing must occur all the time in his work?
So, it was now apparent the burst hose was the result of overheating and not the cause of it, that it was likely far more damage would have resulted and so it transpired. I soon found water had leaked into the cylinders, so major repairs were required. Not being willing to pay a mechanic to carry out this work, I set about it myself, having done similar work on a variety of other cars in the past. What I found was even worse than I suspected.
Firstly, I couldn't remove the wheelnuts without the use of a 4 foot breaker bar (a short scaffold pole!), so a roadside wheel change would have been impossible. Secondly, the crankshaft pulley bolt also needed that same breaker bar to release and thirdly, the retaining bolt on the auxiliary belt tensioner wasn't even finger tight, so it could have fallen off at any time!
When I eventually managed to remove the cylinder head - quite an exercise taking a very long time on this car with its severely restricted access! - in addition to the cylinder water, I found the exhaust valves and valve seats were badly pitted, but that it had been fitted with the later multilayer and shim head gaskets during a previous head gasket repair.
So, the head was sent off for skimming and sent off again with new exhaust valves for professional valve lapping, after I found my own efforts at removing the valve seat pitting were proving ineffective. In the meantime, I cleaned up the piston heads and block before measuring the liner projections above the block with a steel rule and feeler gauges. These were found to be between 0.00mm and 0.05mm, i.e. virtually flush. Looking online I discovered the best headgasket for these measurements is the elastomer gasket, NOT the multilayer one that had been fitted, so I ordered the correct gasket set.
Amazingly and very serendipitously, at this time I bumped into a couple of guys at our local fete, who both had very extensive MGF experience, one having actually worked as a manager for MG at the time of my car's manufacture. They approved my choice of gasket and told me the pitted valves/seats were an indication of water ingress over a long period. This was also pointed out by the engineering company skimming the head, further confirming the previous head gasket fitted was wrong and that this breakdown was probably waiting to happen over a long period, but was then accelerated by the lack of cooling system bleeding.
It was now time to open that bleed screw. After trying every spanner and socket I had, I resorted to using a damaged screw remover after spraying the screw several times with penetrating oil. It eventually came loose but, as expected, it was too badly damaged to be reused. I'd already emailed a major MG parts supplier/repairer asking if they could supply a replacement screw, as I believed at that time it might be a special type. They replied that they could only supply it as part of the pipe assembly, a £95 option I was of course unwilling to pay, especially as I'd realised by then it was just a normal flanged screw, similar to those used elsewhere on the car. But they then added that they found my story interesting and would take note - as they'd never opened that bleed screw before!
I couldn't quite believe this and answered it was critical this screw was opened as part of the bleeding process, to ensure all air was excluded from the system, otherwise air pockets can travel around the engine, causing hot spots that would eventually lead to head gasket failure. I haven't received a reply.
I'm now in the process of rebuilding the head before refitting it to the block, but I did go further and drop the sump in order to clean out all the gunge that had collected in there from years of winter storage. I'm being very careful and, hopefully, the engine will soon purr like new, providing many thousands more miles of reliable motoring.
Moral(s) of the story: research online to find the best practice and the proper parts; download the free, 848 page repair manual to obtain all the correct torque settings etc.; don't trust a mechanic/repairer to do work on this car without first ensuring he has/they have all the knowledge and experience to competently and reliably work on it; make sure the right gasket to suit your engine's wet liner tolerances is fitted; and finally and most importantly, make sure the cooling system is properly bled upon completion. These measures might help eliminate the poor reputation this car has for head gasket failure and will keep your car on the road for many more years to come.
Finally, replacing the timing belt isn't such a difficult job, but you do need to be able to get under the car to work effectively. As I'm renovating a house and had loads of scaffolding on site, the photo shows how I did it.
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Necessity is the Mother of Invention.
