Oil drain check valve test ? - 85 300d
 

I've heard that the check valve in the oil pan that receives the drain pipe from the air cleaner can fail and a motor can suck up oil from the pan? First, is that true? Second, is there a way to test that check valve? Third, if it's bad, is there a write up on how to service it? Thanks a bunch!

Do a search on "oil check valve" to start. Also, look in the DIY section. Dave Morrison wrote up an excellent article on the procedure.

I do not know of a test, but I suspect you would need to take it out to test it, and if you are going to go that far, you may as well have a new, clean one ready to install. They are cheap compared to the time you are going to put into the job. And it is a messy job, I understand.

Have you changed your oil? I found that this helped the problem. I was not sure when the PO changed the oil in my car. Also, make sure your air filter is clean. If it is not, your engine will be straining to get air and will draw it from whereever else it can find it, i.e. up the drain tube.

Richard

Yes, excellent, I found the write up, which is very good. I change oil regularly with synthetic, so I should be good there. Air cleaner is new. So no way to apply vacuum to the down pipe to see if the valve is operational? I may even be convinced to suck on it.

Hmmm . . . I don't see why you could not hook up a shop vac with some duct tape. Maybe use some clear tubing to see if anything is coming up. I would do that before sucking on it. Yuck! I have seen several sizes of clear tubing at the hardware store. The challenge will be to get some that is rigid enough not to collapse from suction. There are O rings that hold the tube tight and if these are old and worn out, you will get a suction leak. If your tube fits real loose, you probably need new O rings.

Dave is the man
 

Another DIY link with pics that I did:

http://www.peachparts.com/shopforum/showthread.php?t=206187&highlight=oil+drain

Dave definately covers the topic - I just add some add'l info and pics...