My 2005 X5 3.0 (51K miles) has produced a sizable cloud of blue smoke upon cold start on three separate occasions, spaced several weeks apart. The clould is large enough to be seen in the mirrors but only last for a few seconds. The car has had 8K mile oil changes with BMW synthetic oil and has never required additional oil between changes. There is no visible exhaust smoke except for these few incidences and this appears to be an intermittent problem. Otherwise, the engine runs like new. The dealer wants me to bring it in for diagnosis at the $120/hour shop rate. Before doing so, can anyone speculate as to what's causing the problem?
Blue smoke is usually oil. Get back there and take a whiff. It has a distinctly different smell than other stuff. Could possibly be water, but that would be white and would not smell like much.
Update: The dealer diagnosed the problem as a faulty crankcase vent valve and presented me with an $875 estimate to replace it. Since the vehicle has low mileage I requested that BMW cover the expense through goodwill and was pleasantly surprised the next day when they said yes. I believe this is the same part that is responsible for the common cold weather issues where the crankcase moisture freezes within the valve causing extremely high oil pressure and blowing out several oil seals & gaskets. Luckily, in my case the oil seepage into the intake manifold was slight and the valve did not freeze. Interestingly enough the replacement valve is covered in rubber to insulate it from the cold. Perhaps this is a case of BMW conducting a "quiet recall" of sorts.
This is an interesting post you have. The other week, I saw an X5 here in SE Wisconsin (it wasn't you was it??) with the same type of thing going on and I thought - wow, what's the deal with that?? Now I know...
+1 on Failed CCV... This is partially what happened to my '00 540 and I was quoted $550 from my local Indy. I ended up buying the part for $50, DIYing and spent the $500 on a brake kit!! Don't believe it when they tell you that the intake manifold needs to be removed. I DIY'd without removing and it took just about an hour including having to tackle other problems (the brake booster hose was so old, it had rigamortous...LOL)! Anyway, the blue smoke is usually the big indicator for CCV failure. I was getting misfires, a "warbling" sound (like bad/slipping belts) and rough idle too. After the replacement, it all went away. EDIT: Just noticed that this thread is from 2010 NOT 2011... Regardless, I recently solved the same issue successfully...
Yes, the crankcase vent valve was plugged. Although beyond the warranty, after some prodding the dealer covered the repair under goodwill.
