1990 BMW 325is - "classic" head gasket leak...

"Ben Martin" wrote

You'd be foolish IMO not to machine the head. Also might as well replace the timing belt.

FloydR

you should be thinking about re-surfacing the cylinder head, however bear in mind that there are only so many times you can do this, when the cylinder head is removed the machine shop etc who machined the head last time (assuming it has beed machined before) should have stamped a number onto the surface to indicate how much was removed last time round. ( in the uk this is normally stamped in thousands of an inch) resurfacing the cylinder head also affects the compression ratio so this should also be taken into account when purchasing replacement head gaskets. its not so critical on petrol engines, and not even sure if thicker gaskets are available for these engines, diesel engines however require thicker gaskets to compensate for anything removed during machining. if its a minor leak you could take a gamble and not bother with machining, but undoubtebly it will not last as long. but as the previous poster suggested you should always replace the cambelt when it is removed for any reason. regards. Steve.

I didn't machine the head because where I lived it was hard to find someone who could do it. So it leaked again right away. But mine had badly overheated. If yours has never been right up at the red end it MIGHT be OK.

After the head is off, you can measure the amount of variation in the surfaces (with a straight edge and feeler gauges) and determine if machining is required at that time.

you must really love that car. id just junk it at 230k miles

Do cylinders 4 and 5 have compression or is it just an oil leak? Are you sure it's the head gasket & not some cam housing gasket?

Why? One of my E30s has almost 200k miles and it runs seriously well. Better looking than most of the cars that replaced it too.