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View Full Version : 1990 535i oil leak at head gasket advice


darren1284
08-14-2020, 11:18 AM
We knew we had an oil leak leaking a few drops after every drive at the front passenger side of the engine. I had hoped it was the timing chain cover gasket, but after putting some fluorescent dye in the oil, the leak is coming from between the block and cylinder head about one inch behind the timing chain cover. A shop already verified that there is no cooling system leak associated with the head gasket by checking the coolant for combustion byproducts.

The engine does have a slightly rough idle which I thought I could fix by replacing the spark plugs, cap, and rotor. Do I replace the head gasket? Do I just live with the leak?

I am concerned about removing the head and finding a crack, though the location of the leak seems like it would more likely be a head gasket failure more than a crack, but I am no expert on cylinder heads.

I am not opposed to doing the labor sometime down the road, but would rather not be buying another cylinder head.
theBMWbeast
08-14-2020, 02:47 PM
Post some pictures of the leak. Seems odd to have an external head gasket leak. I know you said you’ve ruled out the upper timing cover, but might be worth it to replace. Not a hard job. Also the valve cover gasket is right there. That’s why I’m interested to see a pic, is it just seeping out from one spot?
ross1
08-14-2020, 05:12 PM
Given your symptoms I see no reason to suspect a crack.
Head gasket R&R on an M30 is easy.
darren1284
08-14-2020, 05:51 PM
Post some pictures of the leak. Seems odd to have an external head gasket leak. I know you said you’ve ruled out the upper timing cover, but might be worth it to replace. Not a hard job. Also the valve cover gasket is right there. That’s why I’m interested to see a pic, is it just seeping out from one spot?

It is a tough place to get a picture, but I guess it is still possible that it is the upper timing cover and the oil is flowing back along the seam of the cylinder head. It is right there. And if it is just the gasket, which I also think it is, it will be easier and less expensive than my m50 engine (it was cracked).

I guess what I really need to do is wipe it down again and then have my son start it up while I am under watching for the leak.

Thanks for the replies!