[CosminADC]

Hello to everybody, I'm new to this forum, by the way I'm not a forum guy, but this time, I gave BMW another chance and bought an M Tech 335i 2008, imported from Japan, with quite of lots of extras, it has a few of them missing.

When I bought the car it was leaking oil everywhere around the valve cover, it had the check engine light coming on after passing 3500rpm, but still going and not entering the limp mode. that been said, I started to work on the car as it was filthy dirty all around inside outside. after the cleaning process ended, I did some detailing on the exterior while waiting for parts, still didn't manage to polish the Shadow Line, due to missing polishing machine, so I gave up polishing by hand.

First parts came in, silicone vacuum hose and the valve cover gasket. I changed the valve cover gasket and all the vacuum lines, both wastegates, both solenoids, vacuum canisters. changed the valve cover gasket, and then I gave it a start. no more oil, but still check engine light after 3500. So I started to do inspection on turbos and there on the back one I found that the wastegate's rod was disconnected so I reconnected the rod to turbo flap, have put some thread locking Loctite, knowing that is a quite common fault for the back turbo slackening rod. gave the car another start and no more faults on the diagnostics(by the way, I am struggling to use this K+DCAN Inpa cable which is in German, if anyone can recommend something better in english and not being over 100GBP). went for a drive was pulling quite nice, but afterwards it started to do the whistling sound on idle. did some research on the forums and found some answers, following some new parts.
I changed the PCV valve with a RB PCV as everybody recommends this one as the best.
I changed the valve cover with a used one but was out from an 15k miles engine, so before installing I cleaned it very well with brake cleaner traffic film remover and EGR declogging cleaner, until clear water was coming from the CCV(before cleaning did some research of what the valve cover has inside the CCV system so realised since there is no diaphragm I can do the cleaning)
After changing the Valve cover and the PCV/CCV valve, started the car, no faults on the shi**y German INPA cable, idle is a bit rough shaking with variation of 50-100 rpm, when I try to open the oil filler cap there is like a lot of vacuum, don't know how much due to missing Vacuum Gauge, but you need 2 hands to open it.
After it warms up you can hear the whistling form 200meters, so it's very loud and you need a flat screwdriver or simillar to open the filler cap.

It drives me crazy, everything is in good working order since the car runs fine, but still have the annoying whistle, high vacuum and shaking idle.

A link to the video:

If there is anyone who has a solution to this nightmare, it will be very helpful for me. By the way, if I solve the problem I'm buying

[cruizinmax]

It sounds like the pcv flapper line is blocked. The one that goes from the valve cover to the rear turbo inlet normally. This will cause there to be excess vacuum in the crankcase and cause the whistling sound as air gets sucked past the front and rear main seals.

The line you are pulling off in the video from the rear inlet, see if you can pull that off the valve cover side. That will tell you if the issue is with the flapper or in the valve cover.

[CosminADC]

If I pull the flapper hose out from there and blow air with my mouth it works. when is on the the engine back in place if I pull it from the Valve cover it makes the same sound like pulling the filler cap, the flapper is in good working order, tried it and it works only 1 way, the other way blows only through the small hole inside, for fresh air. I know it is hard to believe, but I don't think a valve cover with 15k miles cleaned thoroughly can be clogged that much, the old one I cracked the pcv with a screwdriver to see if it was clogged, nothing, very small residues in there, no hole clogged, so i am 100% sure if i crack this one is the same. I don't want to pay 500 for a new valve cover and then discover nothing changed and the engine still whistling.

[cruizinmax]

I'm certainly not a proponent of replacing parts randomly. If the flapper is in fact working correctly, you have too much volume of air being drawn through the crankcase. I'd double check your installation of the pcv valve. That should be restricting the airflow to a light breeze if you will, not like a vacuum cleaner. There are only a couple of paths for intake vacuum to make it to the crankcase, all involving the valve cover. Valve cover gasket misinstalled when putting the valve cover on?

I mean no offense by this but if these tips don't help you diagnose it, I'd recommend taking it to an experienced technician. Replacing parts randomly on the advice from people on forum is a recipe for wasting money.

[lightmanek]

Flapper has to be connected to the inlet of your turbo, if there is no negative pressure on deceleration, the valve will not always open and cause too much vacuum in the cover.

I had the same problem when converted my car to M18 valve cover with external PCV on both high and low side while retaining flapper. As it was not connected to the turbo inlet (Single Turbo) engine started to whistle, but not always. Our solution was to add additional valve between intake manifold and M18 cover to keep things in check while we are gearing towards rebuilding cold air intake and provision for flapper valve connection.

The other option is your PCV valve in the cover, take it out and check for damage, sometimes they can get stuck if not installed properly.

Hope this somehow helps in your case.

[CosminADC]

The flapper hose if I pull it from the turbo intake side, does nothing, if I pull it from valve cover, air will be sucked in by the engine, same like pulling the filler cap, the whistling happens either if the hose is or isn’t connected to the inlet pipe. PCC Valve is brand new RB, I am a mechanic as a job but I am specialized in Porsches, which have different system, unlike bnw system CCV without diaphragm. So to answer now the other questions:
Tried 3 different PCV valves from cars without whistle problem, gasket and vacuum are doublechecked for correct installation, valve cover is definetly not clogged, flapper works in hand by blowing in it, one direction lets all the air that I blow, other direction restricts and blows only through small hole inside, no faults on the diag.

[lightmanek]

Originally Posted by CosminADC

The flapper hose if I pull it from the turbo intake side, does nothing, if I pull it from valve cover, air will be sucked in by the engine, same like pulling the filler cap, the whistling happens either if the hose is or isn’t connected to the inlet pipe. PCC Valve is brand new RB, I am a mechanic as a job but I am specialized in Porsches, which have different system, unlike bnw system CCV without diaphragm. So to answer now the other questions:
Tried 3 different PCV valves from cars without whistle problem, gasket and vacuum are doublechecked for correct installation, valve cover is definetly not clogged, flapper works in hand by blowing in it, one direction lets all the air that I blow, other direction restricts and blows only through small hole inside, no faults on the diag.

You have huge amount of vacuum under cover which normally is coming from intake manifold through 6 tiny holes, one in each intake port. They are connected to the valve cover channels and go via cyclonic separator integrated in the cover and is then routed via PCV valve to the main chamber.
Flapper is connected directly to turbo inlet.
When you're accelerating, the positive pressure from the intake is pushed through PCV valve to the valve cover and excess is vented back to the turbo inlet. When decelerating or idling, the negative pressure from intake manifold creates vacuum under valve cover and Flapper lets some "fresh air" from turbo inlet back into valve cover preventing creating too much vacuum.

Now either your valve cover has a problem with PCV valve or a crack allowing bypassing it and sucks all the vacuum it can, where flapper simply becomes too restrictive to let enough air back into the cover or flapper valve is not operating as intended.

As you've already mentioned testing flapper both ways, my attention would turn towards PCV or cover itself. I bet your engine will run the same with or without PCV valve installed.

[CosminADC]

Originally Posted by lightmanek

Now either your valve cover has a problem with PCV valve or a crack allowing bypassing it and sucks all the vacuum it can, where flapper simply becomes too restrictive to let enough air back into the cover or flapper valve is not operating as intended.

As you've already mentioned testing flapper both ways, my attention would turn towards PCV or cover itself. I bet your engine will run the same with or without PCV valve installed.

As you said above, that's what I have knowledge of the CCV system how it works and also you are very correct about the last one, I have also tested with an empty pcv valve, which I have cut and got out everything inside, the amount of force applied to pull the filler cap is the same. I am suspecting there might be something in the intake manifold, which I am going to remove in the weekend and clean and inspect. Then if nothing happens I hope I will have the new valve cover, an Aftermarket one not an original, since the difference is 320GBP between them, for a test the aftermarket one should work. question is, should I use an original PCV that will come with the new cover or the RB one?

Thanks for sharing your thoughts with me. I remembered something else. this whistle had happened after I changed the valve cover gasket and the vacuum hoses, including the one from intake to the BOV's and the one from the main line to the exhaust valve. before doing this it wasn't whistling and the intensity of the whistle has been the same.

[lightmanek]

Originally Posted by CosminADC

As you said above, that's what I have knowledge of the CCV system how it works and also you are very correct about the last one, I have also tested with an empty pcv valve, which I have cut and got out everything inside, the amount of force applied to pull the filler cap is the same. I am suspecting there might be something in the intake manifold, which I am going to remove in the weekend and clean and inspect. Then if nothing happens I hope I will have the new valve cover, an Aftermarket one not an original, since the difference is 320GBP between them, for a test the aftermarket one should work. question is, should I use an original PCV that will come with the new cover or the RB one?

Thanks for sharing your thoughts with me. I remembered something else. this whistle had happened after I changed the valve cover gasket and the vacuum hoses, including the one from intake to the BOV's and the one from the main line to the exhaust valve. before doing this it wasn't whistling and the intensity of the whistle has been the same.

Go with aftermarket if the car is not pushing a lot of boost.
As for PCV, I've used RB PCV on my car when started pushing 23psi+ but it was mostly preventive move and not because original had issues.

If it started after changing gasket, is it possible that gasket got damaged or blown by?



Highlighted are channels used for connecting valve cover with intake. On my engine they are now blocked and PCV is externalized. This helps when running very high boost as it stops blowing valve cover gasket or cracking the plastic.

[SpaceCoupE92]

Did you end up finding a solution? I'm experiencing the same problem and have replaced the valve cover and pcv valve. any help would be appreciated.

[CosminADC]

Yes, change the valve cover, I tried with a chinese replica someone gave to me as new never used, and never had anymore of the issues, the problem is located in the valve cover between the walls of the pcv system!