Oil Flowing Down Air Intake

afish01 · Aug 20, 2005

I went to replace my mass airflow sensor on my 1990 240 DL yesterday and I found that engine oil has been flowing downhill (against the flow of air) from the intake manifold all the way to the air filter box. As a result, the old MAF was all gummed up with dried/burned oil, and I supposed that could be the reason it went bad. I wiped some of the oil out of the intake hose, but I'm guessing it's going to keep leaking oil down through there until I figure out what it's doing. Oil also likes to seep out from the "add oil" cap, so I wonder if there is some connection--I was thinking maybe the PCV valve could be the culprit, but I have no idea where it is on this car so that I can test it. Or maybe it is one of the two vacuum hoses that join up with the intake hose just before the throttle body.

Do you have any ideas why the engine oil is seeping in there? I would like to correct this problem, because I imagine this can't be a good thing. Maybe one of you could step me through some troubleshooting methods I could try.

Thanks,

Adam

Tech · Aug 20, 2005

Follow one of the hoses from the intake hose.It goes back to the intake to the flametrap.It could be clogged.Also follow the small hose from the flame trap and make sure where it goes to the intake isn't clogged.

afish01 · Aug 23, 2005

I think I checked the hoses that you are referring to. I could not get the end of the bigger hose off of the T-fitting where the smaller hose joins up. I didn't have time to wrestle it off the fitting, so I wasn't able to check to see if it is clogged. But I got the smaller hose off and it was not clogged, but it was full of runny motor oil. Where is this stuff coming from? The whole intake and all the smaller hoses plugged into it are all full of this oily grime. Is this a sign of a bigger problem? What do I try next?

Thanks for the help!

Adam

Tech · Aug 23, 2005

You need to get the other hose and see if it is clogged.

hgshaw · Aug 24, 2005

I had a clogged flame trap a while back. It caused the vehicle to lose virtually all of its oil on a 200-mile trip. Can be bad. Note that iPD sells a flame trap modification that makes changing these a lot easier the next time you have to do it.

Guest · Apr 29, 2006

I noticed the same thing on my 1991 Volvo 240 Sedan (no turbo), but when changing my air filter. It was soaked 1/4 way up with oil. I attached a picture:

[attachmentid=1777]

and plan to do the clogged tube check soon. I will post my results and if anyone has a suggestion, especially afish01 and his status with the problem, about the remedy please let me know.

Thanks

Oil Flowing Down Air Intake

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