[CantComplain]

Hey All-

07 335i. I'm just putting my car together after tearing into it for walnut blasting, valve cover, oil filter housing, PCV valve, vanos gaskets and a few other things. It had leaked badly for some time, and there is a lot of buildup of sludge under the valve cover, primarily/especially at the back of the engine.

I'm looking over everything before I put it back and I'm to the crankcase vent hose right now. it's the one on top of the valve cover with the square connector that's a PITA to remove. I did not break it taking it off and was planning to reuse it.

I can hear it rattle a little, and that sounds normal. And I can blow in one direction and it seems unobstructed. But when I suck (or blow from the other side) I can hear the thunk of the flap but it's not a perfect seal and a certain amount of air is still passing. Is that normal? They're only $30 so no biggie but hey $30 is $30 and I'd rather not wait for a replacement if there's no benefit.

Any input appreciated. (except blowing/sucking my hose jokes )

[135Pats]

It's a check valve that's meant to help keep some vacuum on the crabkcase in certain situations. So long as it can swing open and closed freely, It's a very simple part that you can reuse

[CantComplain]

Originally Posted by 135Pats

It's a check valve that's meant to help keep some vacuum on the crabkcase in certain situations. So long as it can swing open and closed freely, It's a very simple part that you can reuse

Thanks, appreciate the reply. It can swing open and closed freely, it just doesn't seal completely when closed like the other/cylindrical PCV. I'd say there's about a 50% reduction in airflow. Does that sound about right?

Clearly there was something going on under the valve cover. Every picture I've seen of the cams in an N54 were at least somewhat clean. Mine's a varnished sludgy mess and i guess I'm holding out hope that it's something that failed that I can replace.

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[Sgop335]

Originally Posted by CantComplain

Thanks, appreciate the reply. It can swing open and closed freely, it just doesn't seal completely when closed like the other/cylindrical PCV. I'd say there's about a 50% reduction in airflow. Does that sound about right?

Clearly there was l]

Its a bi directional valve #9 in pic - one direction is ventilation during boost conditions, other is make up air when the pcv valve vents during vacuum. Flow ratio forward to back is about 3:1, so yes not designed to seal.

[CantComplain]

Originally Posted by Sgop335

Its a bi directional valve #9 in pic - one direction is ventilation during boost conditions, other is make up air when the pcv valve vents during vacuum. Flow ratio forward to back is about 3:1, so yes not designed to seal.

Perfect, that's exactly what I was looking for. I'll re-install the original.

Somewhat related, does anyone know what would cause the sludge and varnish? I get that the 15k interval is a bit liberal, but the deposits on the cam covers starting at around cylinder 3 has me a bit confused . I've re-installed the valve cover but didn't try and get it all off. I was thinking running 30w Dino oil, a quart of atf and or sea foam for 100-200 miles to clear some of it out. Any advice on that?

[mweisdorfer]

Originally Posted by CantComplain

Hey All-

07 335i. I'm just putting my car together after tearing into it for walnut blasting, valve cover, oil filter housing, PCV valve, vanos gaskets and a few other things. It had leaked badly for some time, and there is a lot of buildup of sludge under the valve cover, primarily/especially at the back of the engine.

I'm looking over everything before I put it back and I'm to the crankcase vent hose right now. it's the one on top of the valve cover with the square connector that's a PITA to remove. I did not break it taking it off and was planning to reuse it.

I can hear it rattle a little, and that sounds normal. And I can blow in one direction and it seems unobstructed. But when I suck (or blow from the other side) I can hear the thunk of the flap but it's not a perfect seal and a certain amount of air is still passing. Is that normal? They're only $30 so no biggie but hey $30 is $30 and I'd rather not wait for a replacement if there's no benefit.

Any input appreciated. (except blowing/sucking my hose jokes )

You should change out the PCV and vent hose / valve every 50k.

Rob Beck makes the best PCV valves in the business.