Smoking leak at firewall can't ID

[Fedaykin528e]

Perplexing problem ...1984 528e - after pulling off the highway, or stopping after a sustained cruise at highway speeds, I get oil smoke belching from between the engine and the fire wall.

It looks like there’s oil hitting the exhaust downpipe right at the fire wall, and I cannot figure out where it’s coming from. Valve cover gasket is new, camshaft plug things are new. I read somewhere in the forum that it’s possible for Powersteering fluid to make its way there on the highway, but I see no evidence of that. If it was the main seal it would be a puddle on the pavement, and there’s no puddle. I do have an ATF leak from some hose between radiator and tranny, not sure this is the culprit. As far as I can tell, the engine oil level is dropping slowly.

It seems like it’s getting worse, and I’m afraid I’m missing something obvious. Has anyone else had this particular problem and can share some advise? Cheers!

[db9]

basic questions and not intended to insult your ability (I hope that comes across the way I intend)

is the smoke oil or coolant (smell)?
did you have the issue before the new gasket and cam plugs?
any leak traces on the back of the head or down the corner?

Any video or pictures?

[Mike W.]

The key to finding oil leaks is to pressure wash/degrease the area in question, then closely monitor it. Once it's clean it's easy to see where it starts getting oily first.

[Fedaykin528e]

Yeah, I have to get me a mechanic's mirror. I've had this issue for a while, and changed the front camshaft seal behind the distributor hoping it was blowback from that common leak. Either it's two separate issues, or this is the issue.

I will degrease and try my damnedest to find it. I couldn't find an analogue to the duck gasket on the M20 on RealOEM, not sure what else could be leaking back there. Does anyone have a schematic of what passages in the headgasket are oil vs coolant?

[Dub-Nub]

A few bits of information

A leak from the read of cylinder head can be from valve cover or rocker plugs.
A leak below head can be from oil sprayed from head gasket, but highly unlikely that enough pressure would build to spray and you couldn't physically see it.

If the smoke is traveling upwards from the tunnel then you could have a leak from transmission that's coming upwards.

Here is what I would do. Take your phone and do a video, it will catch what you cannot see right at that level. GO SLOW with the camera so you can review it properly.

[Fedaykin528e]

Update: Really scoured the gritty oily hell that is the underside of the engine/subframe and found that oil was collected and pooled in the boot to the oil pressure sender connector... like squeeze it and oil squirts out like some sort of steel bovine.

I would guess now that with sustained cruising rpm, the pressure is enough to drip drip into the wind, getting caught on the downpipe. I'll throw a new sender at it when I get a chance.

I took some photos, which I'll upload.

[byterrr]

Was it similar to this?

https://www.youtube.com/embed/o8FlujT7uN4

This is a video of my car after the engine has been turned off with smoke still emanating from the area near the firewall (possible oil pressure sender?) Still haven't been able to isolate the source of the issue

[Fedaykin528e]

Looks about the same, yes. I'm hung up because this seems to be the ONLY THING ON THIS CAR THAT IS 24mm!!!! Will get a deep socket soon.

Was it similar to this?

https://www.youtube.com/embed/o8FlujT7uN4

This is a video of my car after the engine has been turned off with smoke still emanating from the area near the firewall (possible oil pressure sender?) Still haven't been able to isolate the source of the issue

[byterrr]

Please keep us updated as I'm going to tackle the same thing soon and the insight will be valuable!

[byterrr]

I was possibly thinking it could be from some part of the exhaust manifold as I couldn't see any oil leaks elsewhere but now I'm leaning towards this being the culprit

[Fedaykin528e]

To close this out, I'm fairly certain this is a transmission input seal leak that is getting thrown onto the hot exhaust. I've been running it like this for 4 years with no issues other than smoke on the hottest days when I get off the freeway.