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Join Date: Mar 2004
Location: New Hampshire, US
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Oil Leak at base of dipstick
Hello folks. I have posted this on E46 fanatics and posting it here as well.
I need expert help, please.
I have 325i 2002 vintage, manual. It sprung a leak recently kind of weird: oil get pushed from the oil pan through the o-ring of the dipstick tube. First I thought I damaged that o-ring last year when I was replacing CCV. So I went and replaced that o-ring again. To my amazement, after about 3 minutes of idling at various rpm I saw oil bubbling there again. OK, I disconnected CCV return oil line from the dipstick tube, took clean clear tubing, stuck it into the drain pipe an blew air with my mouth, be careful with assumptions: I have clean clear plastic line between my mouth and drain line. Basically, I checked if there are any obstructions in the line. No everything went fine air blows inside with very little effort. I started engine and, without connecting drain line, of course no pressure inside oil pan, so no oil leak, from drain line after a few minutes starts coming some steam, like if you have oil cap off. Seems normal.
My next step in troubleshooting was disconnect line from valve cover to CCV. OK, start engine, wait, no oil leak. OK it does make sense.
My last step in troubleshooting was disconnect lines from the rail above intake manifold to CCV and check them for obstruction. The interesting that I was able to duplicate oil leak just with pressure from my lungs, just by blowing air into the one port of CCV valve, while plugging other port with my thumb.
Well, that how I deduced, that all lines and CCV are clear of any obstacles.
Then good question; why excess pressure form inside the engine didn't get into intake manifold? Does it mean that engine has insufficient vacuum on intake? But than OBDII should through warning light, right?
Any way, I am puzzled and asking for piece of collective wisdom. Does any one has a suggestion?