crankcase pressure remains after new vent valves - help?

[Sgt. Schultz]

Replaced both crankcase vent valves this weekend @ 111k due to excessive pressure coming out of valve cover gasket. Pressure unfortunately remains (enough to 'float' the cap if I place it on w/ hand on top of it), and now I have excessive emissions CEL - cleared it, came back w/in 15mi. Car runs brilliantly otherwise, never any CEL before.

Smoked like Spy Hunter first 1.5 days after install, seems to be gone and assume was just built up oil blowing out from failed valves.

I've also had - for lack of better description, sorry - a tapping sound coming from bellhousing for past 2mos... like tiny wooden bongo's typing out SOS. Put car on my lift, it's def not rod bearings or cats or anything else... maybe dual mass flywheel? My BMW race shop (really good) thinks it's rear main seal... but I've got no oil leak, and don't see how RMS would make a sound?

Questions:

anyone experience this?

any insight?

what's ramification of just ignoring it and driving as is?

I'm 'decent' tech-wise, but this one's got me befuddled... TIA for any help here, all!

[Throatpunch]

Crankcase pressure means excessive exhaust pressure passing the pistons. Did you get a compression test to make sure the engine is healthy?

[Sgt. Schultz]

haven't yet - car still runs like a scalded cat tho, no change in my 22k thus far... and that'd mean rings, which would be oil consumption (I've got none) and purple smoke in all circumstances

[Sgt. Schultz]

wow, no one - nuthin? Huh.

[bmwpower603]

Those are oil separators.

The pcv valve is on bank 2 at the back of the engine.

[Sgt. Schultz]

THANK YOU - is bank 2 passenger?

[bmwpower603]

No bank 2 is the drivers side.

[Sgt. Schultz]

thanks - found this https://www.m3post.com/forums/showthread.php?t=1349252 about PCV valve... does not at all look easy to replace

think this may be my pressurization issue?

[bmwpower603]

You need to have it diagnosed professionally. Or use ISTA on it before you throw parts at it.

It will tell you the likely issue.

[Sgt. Schultz]

I've had 2 shops who deal near exclusively w/ BMW maintenance (one also a race shop) look at it, both befuddled

I don't mind $25 for the PCV valve, it's the install that looks to suck royal unfort. Pick up part tomorrow, wish me luck - will report back.

[bmwpower603]

You need to bring it to bmw.

Has someone scoped the cats? Maybe they are clogged.

Throwing parts at the car won’t fix it. You need to know the issue.

[Throatpunch]

Nothing in an NA engine could create enough pressure to float a cap unless exhaust pressure was relieving itself past the rings. If u had a boosted car i could see the intake side pcv issue

[Throatpunch]

Did u get a leakdown test done after getting new valves installed? Did u cut new seats into the cylinder head?

[Sgt. Schultz]

thanks for the continued thoughts, I appreciate them all

no new valves - crankcase vent valves, yes - so no seats cut into head / leakdown test

my thoughts on rings... car would have poor performance, and smoke at idle and under load, and use oil... I've got none of that.

On cats clogged... again... would have notable performance degredation and sound would change (BTDT).

I'm guessing rear main seal has hole which is producing acoustic tapping sound and creating a ventouri of air thru the case / cap as the flywheel spins.

If the PCV doesn't solve tonight (if I'm even able to get it out/in!), it'll likely be for sale if anyone interested... awesome car otherwise, pains me to ditch it but I'm not in position to do RMS and obligatory while in there clutch unfort...

[pbonsalb]

If the RMS was bad, wouldn’t you see oil dripping under the car?

Are you using a high level scan tool?

No problems in previous 22k miles you drove the car? How many miles on it now?

[Sgt. Schultz]

totally agreed about RMS, exactly what I said to the 2 shops but they still think so?

used new Snap On scan tool for codes, none related to this oddly enough

zero prob otherwise, car runs (currently) fantastically! 111k now...

I'm shocked no one else here has experienced similar

[Throatpunch]

you can think of crank case pressure and oil burning as two seperate symptoms and not necessarily related. Remember during compression it yields roughly 150-180 psi of pressure which can leak past rings. If the oil control rings are fine it will limit the amount of oil that passes the crankcase into the cylinder thus preventing smoke from occurring.

[Sgt. Schultz]

picked up the $30 PCV and tried to install

after giving it the 'ole college try... _there_is_ZERO_WAY_ I can get that - despite reading here someone once who had (no details on secrets used unfort)

While I *may* be able to get it out, I cannot see how I'd evvvvvver get it back in... and get the 6mm torx bolt in w/o dropping it. Nope. It's soooooo far down the block and no way to get any hand in there, uh uh.

Appt in 2.5wks for shop to try, hoping solves - will report back. Thanks again for all thoughts shared, I appreciate it...

[bmwpower603]

There is a bracket that needs to be removed in order to access it better.

It’s the bracket holding the rubber coolant hose. There’s two bolts one up top, and one on the side of the engine that you can’t see.

Try using butyl tape when reinstalling bolts, or removing so it doesn’t fall off the torx bit.

When remove the PCV valve. Pull it off with the hose attached and it should pop out.

[Sgt. Schultz]

OK, thanks for that tip - I'd seen that and also determined there was no way I'd be able to remove that bracket lol / d'oh

Any protips for that? Any idea on which size / type bolts?

SO DUMB... ugh.

[bmwpower603]

You can see the bolt on top, and the one on the side of the engine is the same size. Torx 30 I believe. It’s a gold bracket that needs to be removed. It’s pretty tricky. Because the coolant hose on the back of the engine is in the way of one of the torx bolts. And is also in the way of the bracket.

If you can manage to get those bolts off. Swing the bracket up, and I believe you can put it to the side. Take pictures. To make sure it goes back on correctly.

[Sgt. Schultz]

shop finally got me in

replaced $30 PCV on back driver's upper crankcase (removing secondary air was critical), 3hrs shop time later - and...

...no change in case pressure nor bamboo tapping sound from lower bellhousing

super

next step is compression test (I really don't think that's it... never heard of any ring issues in any of my ///M's?) - or - punt... oy