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Q: smoke from exhaust pipes on 2003 BMW X5

i want to know what could cause bluish grey smoke to all of sudden come billowing out of the both exhaust pipes at the same time after riding in the car for about 3or 4 miles and 10 or so minutes of operation?
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Blueish grey smoke from the tail pipe is oil smoke (black smoke from the exhaust is usually excess fuel, white steam from the exhaust is usually due to a blown head gasket).
Oil smoke from the exhaust means oil is entering the combustion chamber and being burned in the cylinder before being expelled out the exhaust. Oil can enter the combustion chamber due to a damaged or worn oil control ring on the pistons, or worn valve guides or worn valve guide seals. Before assuming the worst check the engine oil level, could it be overfilled? Get a friend to follow you on the freeway, on steady acceleration does blue grey smoke bellow out of the exhaust? That would be a sign of worn rings. If you get clouds of blue grey smoke when you first start the engine or after the engine has idled for several minutes and then is accelerated that may be a sign of worn valve guides or worn valve guide seals. Do you smell a burning oil smell or have blue grey oil deposits on the rear bumper. Get it checked as soon as possible. If you do indeed have engine damage its best to attend to it as soon as possible.
I have had several cyclone seperators go bad and cause this problem. You need to check your vacuum, with a water/vac gauge, if the vacuum is low the seperator or hoses could be clogged or the seperator could be busted on the inside.
I had this exact problem, it was a differnt car though! It was a turbo 300 z! It was horrible but wouldn't do it in the driveway, it waited 'till I got into town and stopped at a stop light! I freaked and spent a fotune replacing the turbo, all the vaccum lines, redid the heads, and so on. After almost 4500 bucks in parts and 3200 in labor I got it back, got to the first light and blam, I couldn't see the car behind me! It turned out to be the PCV VALVE!!!! A freakin' $3 part! Hope it helps! good luck!
I have same problem, but it followed an issue of blowing smoke all the time when starting, real bad. So I went and checked all the usual items, CCV, hoses, separator, and replaced them all, CCV was OK, no sludge or torn diaphram, but replaced it anyhow given it was such a huge pain to get off with manifold in place, so looking at separator, it too was clean, but replaced it anyhow for same reason, but what I did see were the two hoses going to separator were sucked in by vacuum, pinched, and when I pulled them off, they had sludge patially blocking hose, so I replaced both of these hoses as well. OK, to top it off, I replaced the bottom separator hose and even the small drain hose going back to crankcase.

Major smoke issue was gone, thank God, but I am now seeing smaller degree of smoke come out of both tailpipes after about 4 or five low RPM driving when car is fully warmed up. This has been repeated several times so it is as if something is electronic, as in sensor of some kind? If I shut car off for a few minutes, then no more smoke? Drive it again for a 3 or 4 miles and it starts to smoke again. This has me stumped, any ideas.

Good Morning! Please could you resilver your problem of smoke ? I have identical problem to yours. Ja replaces pcv valve ( not original) joint cover vslvulas cleaning
hoses and osv . Fimo decreased but not stopped . admission collector continues sucking oil and queimandi with gasoline. Thank you for any help!
As I had previously posted, I still had residual smoke after replacing everything, and low and behold, it was because mufflers got filled with oil, only way I discovered this was hearing a sizzle when shutting vehicle off after drive. So I flushed with engine cleaner and hosed out, smoke stopped, so you may have the same situation, so listen to your mufflers after shutting down. Crazy, but it has been almost two years and 30K and not another whisper of smoke out exhaust. I know it is hard to believe, but mine was sucking quarts of oil into intake manifold, so now I know where oil was going which didn't burn, it was being dumped into exhaust system, didn't kill the O2 sensors either, strange, but I ran Lucas gas additive every tank to make sure all carbon is cleaned out from this issue.

Good luck,
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