The Classic Machinery Network

Hello chaps, i'm back after a year and a half with a more fundamental problem! The Leyland 4/98 engine serial no. 31207 on our JCB 3C Mk2 (1975) is leaking coolant into the engine oil, turning it into brown milkshake. Dad bought the machine in the early 80's from the original owner and we've never had a need to have the engine apart until now. So i'm just asking you guys in your experience with these engines what are the different ways in which coolant can get into the engine oil? So far i've learnt it can be head gasket failure or core plugs in the head leaking?
cheers
Mike

You could also have porous or cracked liners,perished liner o rings,a corroded block where the bottom liner locates or a cracked head. Take the sump off and get a pressure tester on to the radiator and see if you can spot where the water is coming from. Maybe take the rocker cover off too. Can't remember if the core plugs are screw in or hammer in in the top of the head but a pressure test should show up a leak anyway.

Thanks agrimax, is it possible to replace the head gasket without pulling the engine out of the machine?

Yes it is and likewise if you need to remove the liners. Don't forget to disconnect the oil feed pipe from the block to the head before lifting the head off. It's below the exhaust manifold and can be easily forgotten about.

Thanks for the advice, cheers.