About 18 months ago I restored the engine of my TA. After a few hundred miles, water started to disappear from the radiator; maybe half a litre a fortnight. I tightened the clips on the hoses but the leakage continued unabated. I then noticed brown water run marks, apparently from the cylinder head, down the driver’s side of the block just below the front head stud. I took off the cylinder head, terrified of finding that I had cracked the block in tightening down the head. TG it was OK.
I replaced the head, using Wellseal on the head gasket and filled the radiator. After a day or so, water drops could be seen down the side of the block in the same place as before. There were also water runs down the side of the block beneath two other head studs.
I then noticed drops of water on top of the nuts which bolt down the head, and finally the penny dropped. On my engine at least, the head studs protrude into the water jacket. Water was oozing up the thread, through the stud holes in the head gasket (I obviously hadn’t put enough Wellseal around them), past the studs through the head, up the thread of the nuts and out into the world. The reason that it didn’t leak at first was that I had used plenty of grease on the stud threads and it had taken some miles before the grease had melted away.
Next time the head is removed (hopefully long after my time) it would be advisable to remove the studs from the block and put them back with an appropriate water sealing compound. Pending that, I removed the nuts one by one (including the ones inside the rocker box cover), wrapped PTFE tape round the threads, selected pristine new washers and replaced the nuts. They haven’t leaked since and that’s about 2,000 miles ago.
Realising that water could also have oozed past the nuts inside the rocker box cover and into the oil, I loosened the sump plug and sure enough, quite a bit of water came out before any oil. The inside of the breather pipe was also thickly coated with an unspeakable, slimy grey oil/water emulsion. It was a narrow escape; the engine could so easily have melted main or big end bearings or seized up entirely.
Some time later I replaced pitted cam followers with newly ground ones. This entailed removing both cam follower blocks. When the front one was taken off, water came out of the front bolt hole. If I say it pxxd out it will give the right idea. On my engine at least, the bolt hole obviously breaks into the water jacket. I sealed the bottom of the hole with an araldite/PTFE plug and it seems to be OK, though I now keep an eagle eye on the water level in the radiator. To be looked into next time the engine is out . . .
So, you MPJG owners, if your water level drops, check the two obscure leakage paths I’ve discovered before doing anything more radical !
Lastly, when first started after a few days of not being used, the clutch sticks and it is impossible to engage gears without a terrible grinding. With the ignition off, I have to push the clutch fully down, put the car in gear, brake hard and pull the starter. The car twitches, the clutch un-sticks and the engine spins over. Thereafter it’s fine. However, it doesn’t seem like a nice thing to do.
Has anyone else experienced anything like this?
Isle of Wight