Head Gasket

[Rainman66]

I just purchased a 1984 325e from a friend who thinks it has a blown head gasket. It was loosing water and running somewhat hot. He put some form of stop leak in it and it was better. Now I have the car and the coolant is a mess. Looks like gray milk and quite oily. I pulled all the plugs and did compression check according to the book. Book value said compression should be 142-156 PSI and on this motor it was 180-185-182-180-180-185. I did notice a pressure build up in the coolant reservoir as air escaped when I removed the cap. The compression values makes me think the head gasket is not blown, however pressure build up in the cooling system makes me think it is blown. Any ideas?

Doug

[OreoGaborio]

i'm not sure what the compression should be on an eta, but make sure you're lookin at the 325e numbers, not the 325i numbers... very different engine, even though they're very similar (ie, 142-156 PSI might be stock for the m20b25, not the m20b27.... but i could very well be wrong... just something to double check)

second... if your oil looks like chocoalate milk & is frothy.... yeah... coolant's gettin in there somehow

[Matthew]

Coolant in the oil (mayo) is normal for a head gasket failure, but if there's oil in the expansion tank the cylinder head may be cracked. If the engine's overheated, the head may also be warped.

Good compression results plus effective treatment with stop leak IMHO point to a crack in the head.

A motor engineering shop can pressure test the head for cracks, and also skim it for surface uniformity. It is possible to TIG weld a head crack, a repair that could last for many thousands of miles. HTH