Intake manifold caked in oil
 

I pulled the air intake on my '83 240D this evening so that I could replace the manifold gasket. I had a clicking during acceleration and had somebody tell me that it was an exhaust leak. When I pulled the manifold I found it caked in oil internally all throughout. Is that a product of age or is it a sign of a separate issue/failure such as a bad oil water separator or an EGR valve stuck open?

On China Blue it was really gunky and I would say it was the EGR. The EGR was caked to the point of being covered on some places 1/4” thick and oozing out. Also does your cam (valve) cover vent into your intake? I suspect that is some of that.

I know one of my vacuum lines to the EGR is broken, I wonder if they are normally open. Yes there is a vent hose over to the intake from the valve cover, good thinking it makes sense that would deposit oil over time.

Adding a catch can to the valve cover breather tube would reduce the problem. It is likely a combination of what an EGR does and some blowby.

Good luck!!!

That sounds like a normal accumulation of soot from the EGR and oil mist from blow by via the breather system. On my 606 I was able to remove the gunk from the head using a spoon shaped spatula. On my engine I could reach the back of the intake valves and scrape the entire intake port as well as about 6 inches of the manifold.

+1

After installing a Provent catch can a while back, I peak down the intake from time to time. 100% bone dry.

The Mann Provent AOS? What size are you running? I use a 200, somewhat arbitrarily picked.

Ditto and ditto.
It’s also the easiest to find.

Any tricks with installing the catch can?


Jeff

I'm also interested in knowing about installation. Do I remove the OEM oil catch?

Oily Intake Manifold
 

To some extent this is normal .

The E.G.R. valve is very often gunked up and partially open all the time .

Also the oil mist recovery system is designed to put oil back into the fresh air stream .

Doing regular hot oil & filter changes instead of the usual once every year or so will help .

Also, not floating the valves on every up shift reduces the amount of oil most recirculated .

No tricks per se, just installation. If you do a search, you’ll find a post of mine with a bunch of photos

Typical for a diesel intake and the first generation of direct-injection gasoline engines. Some of the latest DI engines added a small gasoline injector right after the throttle plate to keep the intake passages and valve backsides clear of gunk. Without that, DI engines have required removing the intake manifold for an internal cleaning every 50K miles or so, and owners don't like those repair bills. I have never removed my intakes, but probably should at least inspect them internally with a bore scope. I removed the EGR years ago since you can't maintain those vacuum controls.

Dang, I gotta do this as well. Is there anything holding the manifold on, other than the 4 nuts I see? The nuts seem to hold both the exhaust manifold and the intake manifold on.

Also, is it generally okay to re-use these nuts as long as they're not rusty? I see some people suggest the copper nuts, but are they necessary?

There are actually 5 nuts, the one that is hard to find is toward the front of the car, I will see if I can get you a picture, I still have mine disassembled. The nuts hold both intake and exhaust, once they are undone you could pull the intake by itself of you need to though.