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I seem to have developed a weep from what looks like the block and head just where the engine number sits. Any suggestions what the most likely culprit is? Please don't say head gasket as I am off to the IMM and might set fire to it if so. Hahaha. I have lost half a pint of coolant and also noticed rusty scale and weeping from around the thermostat. Car runs lovely. Any clues? Cheers. Mark

I'd say it is head gasket, however, before getting in to a lather over this, drain the coolant, replace with plain water and run it about for say 500 - 1000 km, then if it has stopped weeping, drain, flush and replace your coolant.

Maybe a re-torque of the head would also help.

Small possibility it is a leak from the thermostat housing. A leak there can pool on the block where the number plate is making it look like a head gasket issue.

My 1275 Healey Sprite used to leak slightly from the head gasket, in the way you describe, it was a professionally modified engine with top of the block & cylinder head surface ground, I never found any particular reason for it & there was no coolant getting into the oil, nor combustion gases getting into the coolant. Just a very small leak to the outside. I would try Spider's advice, the weeping I had was much reduced with plain water. Maybe this would be frowned upon, but half a can of Wynn's Stop Leak cured it! I covered over 60,000 miles in 2 years in the car & had no problems resulting from that slight leak. As already suggested the water may be creeping down from the thermostat housing, another thing I would suggest is to make sure the temperature sender unit is fully sealed, particularly if it is the capillary type. Definitely check the torque on the head studs.

I'm with cheleker - good chance it's the thermostat housing.

Some good advice above.

I'd agree it could be thermostat housing leaking and pooling around engine no. plate. Or more likely a small head gasket leak on that front edge.
I recently did a rather quick head swap on a 998 (Lapped in valves but no head re-facing) and torqued it down as per the old manuals to 40lbs. On starting up it was fairly gushing out of the area you describe. So I increased the torque to about 50lbs.. better but still leaking. So against better judgement I increased the torque a little further giving a few judicious extra ounces on the nuts in the problem area. That cured the leak and it has given no issues after about 500 miles.
I' ll probably have permanently warped head but Ive got a few standard heads knocking around to re-fettle and use on the daily driver. I probably would have re-torqued at some point anyway by now, but all seems fine so I'm leaving it.

So I would try a bit of judicious tightening. But obviously don't go too mad as thread stripping is the next problem.

Incidentally what is the highest torque anyone has known an A series head to have been tightened to and what were the consequences?

I tightened mine up to "NNNNNNIIIIINNNNNNNNGGGG-GGHHH" (whatever that is on a torque wrench) and sheared a stud. (When I was about 18)

Do not do this. Take it to bits and fix it properly.

A few years back I got a helicoil kit to fix a pulled stud on my 1098 clubman and my mates just had 2 done on his Mk2 Cooper
They don't like abuse hence tq wrench settings

I agree you need to be careful, that's why I said 'judicious'. The figure quoted in the later manuals is 50lb. Keith Calver suggests between 48lb and 52lb with 'dry' studs. So going slightly over 50lb in the problem area isn't likely to do much harm.

But for further info on the whys and wherefores of not overtightening head nuts see:http://www.minispares.com/article/Techn ... 945ed28986

There's obviously a difference between re-torquing following the installation of a new gasket, and re- torquing a head that's been in situ for a long time as is probably the case with the OP. Probably less likely to be satisfactory as the gasket has started to fail through wear, so no amount of re-tightening will help.

Folks, I managed to resolve the 'alarming' situation and made it to the IMM too. It was a Yazaki type sender unit which fits in to a brass adaptor in the side of the thermostat housing. It simply would not pull up tight enough to the adaptor and as a result it weeped round the back. traced down the water pump and the front of teh block leaving an ugly looking weeping sore. I was running out of time for the IMM visit and hit the MK1 forum 'PANIC' button. Thansk for all of your detailed replies. It was nice to see a potential horror problem turn into a minor glitch for one. Cheers. Mark