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BMW PCV Valve – Crankcase Ventilation / Oil Separator – M54 and M52TU 6-Cylinder

June 25, 2010

What’s the maintenance schedule for pcv valve on my 2002 x5 3.0i, and 1999 323i 4door? Why don’t I see this as a maintenance item anywhere? It went on both my cars at around 50,000 miles. The x5 cost a bundle to repair at the dealer. The car blew smoke from the exhaust and had to be towed.

The crankcase ventilation system, on later model 6-cylinder BMWs, is indeed a trouble area (as it is on the V8 models, as well). We haven’t yet taken to suggesting that replacement of all of the hoses and the oil separator be a periodic maintenance item. We typically get into the system when we see the symptoms appear, such as; oil burning, rough idle, engine fault codes that suggest air/fuel mixture problems or oxygen sensor problem and other symptoms that would suggest vacuum leaks in the system’s ventilation hoses or a ruptured check valve diaphragm.  As with your cars, we are seeing these systems having trouble at mileages between 50,000 and 100,000.

(EDIT – 02/2011) – At this time, four years after this was written, we would now certainly recommend a preventative maintenance replacement of the PCV system on these engines.  We are seeing practically all of the M54 and M52TU applications having failed PCV systems in the 60,000 to 150,000 mile ranges.  Considering the potential for catastrophic engine damage, we fully recommend a 60,000 to 80,000 mile replacement .  We have even had customers who require annual replacement due to sludge build-up.

Most (if not all) US model M54 engined BMWs were delivered with the standard warm weather systems.  The kits that we offer, include the hoses and valve assembly from the “cold weather” package.  The hoses and valve are insulated with molded foam insulation.  This can help to prevent the build-up of condensation in the hoses and the separator valve (which leads to sludge build-up and possible clogging of the ventilation hoses, valve or the oil drain hose).  Even if you do not live in the northern climates, these parts are a good choice and will help to prevent the sludge build-up in the system.

See the link below for a DIY on replacing the Crankcase Ventilation System parts:

Crankcase Ventilation System (PCV) DIY

Click below for crankcase ventilation kits:

Bavarian Autosport

  1. Jason permalink

    I have a 1999 528it wagon I think might have a faulty ccv. The car has a rough idle and i can spray carb cleaner about a foot to the left of the throttle body and the engine idles up.
    What do you think and also is there a DIY for this problem? The car was manufactured 11/98. Any help appreciated.
    Thanks Jason

    • You certainly may have a vacuum leak in the main hose that comes from the valve cover to the oil separator valve. This would be in the general area that you have described. In this case, we’d recommend replacing all of the hoses and the valve, using the kit that we offer, as opposed to just replacing the one hose. Problems with this system are so common, that it would be best to just replace all of the parts considering the age of your vehicle. See the blog post link below for a DIY.

      M54 Crankcase Ventilation System DIY

  2. It seems pretty clear to me this should be on the maintenance schedule. It hit my 2001 330ci at age 10 and 72k miles. It spent its entire life in Maryland, where the weather can hardly be considered arctic.

    • Right you are! Thank you for bringing this older Otto question and reply to our attention (originally written a few years ago). We have updated the post with comments on this point.

  3. ariel guieb permalink

    Hello. I just finished replacing the crankcase ventilation system. That was just about the most exasperation replacement I have done. Biggest stumbling block was the “jacket” of the valve. I had to remove it to be able to connect the hoses (wasted money on that one). Without removing the jacket I would not be able to fasten the 2 bolts to secure the valve also. Plus the jacket was slowly ripping as I made several attempts to fasten the valve with the jacket. Eventually I had to remove the jacket.
    One minor thing, you cannot just push the dipstick tube. You must remove the bracket that secures the dipstick tube. But all seems to end well. I just have to test drive the car and see if the RPM needle still fluctuates.
    Thnx for the instructions. Saved me a bundle and I know the job was done right. Cleaned the immediate surroundings too :)

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