CLEAN YOUR VANOS CHECK VALVES!
 

I'm posting this because up until recently I never heard anyone mention to me that I should clean my vanos check valves. I didn't even know they existed!

I've been experiencing performance issues where it felt like the transmission was failing or I was having torque converter shudder. Low speeds around 1800 RPM under load was resulting in jerky acceleration and shudder and it was getting worse. Putting the car in sport mode helped with a smoother experience but it wasn't great. I thought for sure my transmission was going but it didn't make sense how some days were better than others and using sport mode mostly corrected the issue by increasing the rpm and power band slightly.

In the past I had vanos and ignition timing issues. Each time I've removed my vanos valves and cleaned them. I spoke with multiple dealers, and I've read many articles online about cleaning your vanos valves if you run into codes like p0012 or p0015. Not once did anyone tell me about the check valves!

Recently I was speaking with someone and they mentioned 'check valves' so I looked into it and wouldn't you know it there are two little valves hidden on the passenger side of your N52 head that you simply would not know were there unless someone told you. So, if you didn't already know about them, that's why I'm posting this.

In order to access the check valves and remove them it's easiest to remove your front passenger tire and remove the front wheel well protective cover. That will give you the space to access and remove them easily.

I have 250k on the clock and these were never cleaned! After cleaning them my performance issues are gone! The engine runs like new and I don't need a transmission service after-all!

I used this youtube video as a reference on how to remove the valves for cleaning.
https://www.youtube.com/watch?v=VQweif8dHFg

Also, here are a few images I took of my car and the valves before and after cleaning.

Inside wheelwell location
https://xoutpost.com/attachment.php?...1&d=1637645764

Check Valves
https://xoutpost.com/attachment.php?...1&d=1637645764

Upper Valve Filthy!!!
https://xoutpost.com/attachment.php?...1&d=1637645764

Lower Valve Filthy!!!
https://xoutpost.com/attachment.php?...1&d=1637645764

All Clean!
https://xoutpost.com/attachment.php?...1&d=1637645764

Nice find. Wonder if there is something like this on the X5M

Totally interesting! Wonder if that's on the m54b30 engine?
Great [emoji106] job! Well writtened.

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Pretty sure every over head cam engine has similar.


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Yessir. Did the same on my 530xi wagon. Weren't nearly as dirty as yours though when I did mine @ 192k miles. I know this applies to all N52s and would assume all N54s.

Looks like extended service intervals at some point in the life of that engine.

While we're talking about N52/54 common issues. Check your front 4 head bolts for the heads snapping. 3 are under the valve cover and can't be seen but 1 is external just behind the OFHG. Mine snapped (assume the 3 internal ones are too) causing oil leakage down the front and side of the engine. If you know the N52/54s propensities to eat the belt through the crank seal... you don't want that belt getting oil soaked.

Thanks for the note! Thankfully even after all this time I have no oil leaked. I’ll definitely take another look at this though. The only leak I had was the oil filter housing and I changed that gasket a few years back.