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BMW M54 6-cylinder – White Smoke From Exhaust – X5 and Others – Crankcase Ventilation – PCV ?

October 14, 2009

Q I have an ’02 X5 3.0i. When I start the vehicle, white smoke comes out of the exhaust. Is it just moisture? Is it from a bad oxygen/fuel mixture? If so, do I need a new oxygen sensor? I’ve also recently had to add about 3 quarts of oil every 2-3 months in between oil changes. Any help would be appreciated.

A The amount of oil usage that you’ve noted is on the excessive side. You may have a clogged crankcase ventilation system. Late model, 6-cylinder engines have a problem with the crankcase ventilation system getting clogged with oil sludge and moisture. The oil separator and hoses commonly get clogged up due to the long time between the BMW-recommended intervals for oil changes, plus the build up of moisture due to normal condensation, which can cause sludge build-up or freezing in the oil separator and oil drain hose. This is a very common issue and the typical symptom is increased oil usage. The cure is to disassemble all of the hoses and replace the oil separator (refer to the diagram below). Also, we have found that the hoses are usually hardened and tend to crack when removed. It is therefore a good idea to replace all of the hoses as well. The hoses and oil separator are found under the intake manifold. This procedure is not covered in the Bentley repair manual for the X5 00 thru 06 (#BX56).  See our blog post, below, for a full DIY.

Click HERE for Crankcase Ventilation System replacement DIY

Click HERE for DIY video

BMW Oil Separator

  1. Chris Young permalink


    Great blog site. My ’02 X5 3.0 has been having the exact same issue over the past 3 years, usually in January/February (middle of winter).

    Is this “white smoke” issue specific to the late model ’02 X5 3.0? Has BMW addressed this “flaw” in the ’03 X5 models and beyond?

    Many thanks!

    • The crankcase ventilation problems that we have discussed, above, apply to all BMW models that have the M52TU and M54 6-cylinder engines. This covers most of the US model 6-cylinders from 1999 through 2005/2006 (3-series, 5-series, X-series and Z-series).

  2. mike l permalink

    i have an 02 X5 as well. There is an issue with the oil seperator. in cold weather it freezes and the oil builds up pressure. This can cause big damage to the engine. Look into the fix. I cant remember what the process is as mine was done 2 years ago. But I do know it was not covered under warranty. Hope this helps.


    • Yes, the freezing is not uncommon when the weather turns cold. This can cause blown gaskets and seals or can cause oil to be drawn from the crankcase, up through the oil dipstick tube, through the oil separator drain and into the intake manifold …. causing hydraulic lock in the cylinders. At best, the engine will not crank or run. Removing the oil from the cylinders (by removing the spark plugs and cranking the starter) will allow the engine to be cranked and eventually started. At worst, this can cause a bent connecting rod or damaged piston …. and total engine failure.

  3. nicolas permalink

    does a bad CVS could cause the rough idle and 1188 and 1189 codes on a 323I 1999 BMW?

  4. Troy permalink

    I have a 2002 330ci 149K on the motor. I recently purchased your pcv kit. strangely after i got your new letter the following morning i noticed a puff of white smoke and some rough idle on start that went away after a few seconds. I just checked the anti freeze and oil level. The anti freeze level was fine. I did notice very small traces of water (chocolate milk) on the stick. This was noticeable at the top of the stick were no oil is at so i believeing it to be condensation in the dip stick and again at the very bottom of the stick. No sweet smells and i didnt have the rough idle or the white smoke this morning. Is this typical of cars needing your pvc kit or am it looking at something more serious?

    • Your symptoms certainly can be pointed toward the common M54 PCV issues. Additionally, your higher mileage makes this a good candidate for a PCV rebuild.

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