Oil leak

General conversations about BMW E28s and the people who own them.
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Posts: 160
Joined: Aug 06, 2018 12:54 PM
Location: NYC

Oil leak

Post by Notaweekend »

M30b34 leaking oil- hand size puddle left on the ground in garage at work everyday. Put it on lift and although it does seem to have a little fresh oil in the front around the timing case, it’s more significant in the rear. I can see lots of evidence of dripping from the top along the block in the rear.
Changed the oil pressure sensor because it seemed possible it was coming from there.
2 years ago replaced “duck” shaped gasket which I guess could possibly be leaking again.
But I’m more afraid the leak is coming from the cylinder head gasket.
Any thoughts? Hoping it’s not head gasket related because time and space is an issue- lack of a reasonably priced shop to go to as well. Need to figure out soon though because it’s causing a problem at work.
Mike W.
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Joined: Feb 12, 2006 1:00 PM
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Re: Oil leak

Post by Mike W. »

It's not unheard of to leak between the block and head there, but as with any oil leak you're not sure about, you need to clean it first. It's going to be tricky since that's the spark plug side, but you need to thoroughly degrease it so you can see right where it's coming from when it starts to leak.

The standard, either pressure washing or degreaser, followed with spraying with water will do it, but also fill up the spark plug wells. You're going to need to get them pretty dry as the high voltage will want to arc down and short out. A shop vac might work too although compressed air is what I usually use. But you've got to get it dry so it doesn't misfire. I didn't one time and while reving it up to try to get it to burn off and clear ended up blowing chunks of the cat out the tailpipe. The cat got that hot to melt.
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