Classic m20 head gasket oil leak? but there is so much oil!

[Yuri]

Hey guys I purchased an M20b25 from a race team years back and I having some issues. The engine was built with all new parts before the season, crashed on the 2nd race and didn’t run the car again. They had a mls head gasket that started leaking out of the front passenger side of the block after the accident. I ended up re decking the head, cleaning the block and installing an oem bmw head gasket and arp head bolts. That gasket started leaking again within a few weeks. Maybe 200 miles.

This isnt coming from the cam or anywhere, but else, it’s literally dumping out of the corner of the head gasket. I checked the torque specs on the corner bolt and it’s solid. being that this is an oil return line it’s hard to understand how it dumps so much oil.

In checking things out I did realize that my exhaust manifold was a little loose. I took it off and brought it to a machine shop who said it’s was extremely warped because of an exhaust leak on the farthest cylinder from the driver.

I’m wondering if an exhaust leak could warp the head enough to create a serious head gasket leak.


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[Yuri]

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[MrBurgundy]

If you 'decked' the head at a machine shop, it should not be warped on that surface. The exhaust leak in my experience should not warp the head in a way that would cause that leak.

Maybe when you put the head back on you clipped the head gasket when you were dropping it on, but with head studs, that's more unlikely... Were the studs in the block before the head was dropped on, or did you install them afterwards?

[digger]

How sure are you it is not leaking elsewhere and accumulating there ? What gasket brand did you use ?

[hasa]

Same leak occurred in my race engine after I installed o-ringed head. I don't care as it is race car which leaks all possible oils.

[Yuri]

Here is a better picture showing the stream of oil on top of the gasket. The cam seal and valve cover gasket are new and perfect so it's defiantly the head gasket. The head gasket is oem BMW.


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[Yuri]

Maybe when you put the head back on you clipped the head gasket when you were dropping it on, but with head studs, that's more unlikely... Were the studs in the block before the head was dropped on, or did you install them afterwards?

That's a good question. I honestly can't remember, it was a few years ago. But I did do all of the work on an engine stand and felt like a did a good job. The car has sat for a long time with only a handful of miles the past 2 years.


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[calypso rot]

I have the same leak on my 90 325i. First time I did it was with a VR gasket. Wasn't satisfied and got the OEM bmw gasket which was noticeably thicker though over 200 bucks. Still happens, like you my half moons and my cam seal are done.

[82eye]

it's not coming from where it is pooling.

[TobyB]

ARP studs- those are fine thread, and if you torque them to anywhere near what ARP says to, the head itself gets... squished.

Or maybe even cracked. I agree, a return hole should seep or drool- not pool up like that.

UV time?

t

[digger]

Retorque the bolts

[Digitalwave]

I have oil that collects on the head gasket tabs like that, but it's from a valve cover that I cannot get to fully seal.

At first the rocker shaft lock tab was sitting up above the head holding the valve cover up, but when I fixed that issue, it still won't seal fully even with new gaskets and gasket maker applied on both sides. I think the valve cover is warped from being powder coated multiple times (color changes).

[digger]

I have oil that collects on the head gasket tabs like that, but it's from a valve cover that I cannot get to fully seal.

At first the rocker shaft lock tab was sitting up above the head holding the valve cover up, but when I fixed that issue, it still won't seal fully even with new gaskets and gasket maker applied on both sides. I think the valve cover is warped from being powder coated multiple times (color changes).

It’s easy to check if warped, to me the biggest thing is actually torquing the nuts to spec with torque wrench and periodically rechecking several times like 3 times until it “holds” and then after heat cycling several times. The gaskets seem to relax notably under the clamping pressure as it has the cross hatch pattern that has a lot of compliance

[Digitalwave]

Do you know the torque spec for the valve cover?

[88Sedan]

I have a thread of my own going with this same issue. I spent hours degreasing my new to me e30/m20 and it pools up in the same place as yours. Will be following this thread.