head gasket

[DoyleL]

Im pretty sure the head gasket has blown in my 88 mini. found mayo on oil cap. How difficult is it to replace. How expensive is it to replace and does any one know a mini friendly mechanic in the north east.

[DaveC]

Is it overheating?
Oil in the water?
Water in the oil?

If it is just mayo on the oil cap it could be that it is only getting short runs and there is condensation building up in the rocker cover. Are all the breathers clear?

[Billy]

Do you know anyone with a compression tester. It looks like a ordinary gauge with a tube that can screw into where the spark plug fits.

It will tell you straight away if there's no compression on one or more (adjacent) cylinders and only takes 5 minutes.

Billy

[keith]

not as accurate as the compression tester is to have a look at the spark-plugs. a low compression cylinder will burn differently to a correct one and the plug will look different.
also listen to the engine. it might sound a little ragged.

*also* look for traces of oil in the coolant. harder to spot than "mayo" in the filler cap. some people claim to be able to smell exhaust in the coolant too. ive not been able to do that.

before you pull the head though perhaps a pressure test on the cooling system. a garage should be able to do that for you.

while the head is off it might be worthwhile to de-coke the head and lap in the valves. its likely that they havent seen daylight in 25 years...

although the cast iron mini head is tougher than nails, if you suspect overheating as the cause of the gasket failure, get it checked for warping.