Fellas,

I have a 2000 528i sport, but I have an x5 question. My brother is looking to purchase a 2004 x5 4.8is. It is from a private owner, but the car has 1 year left on the CPO warranty. He test drove the car today, and fell in love with it, but as the car drove away, he noticed significant white smoke from both tail pipes. Could this be a blown head gasket? blown engine? or?? Should he be worried since the car is a CPO? The car has 52k miles, again he said the car drove great.

Thanks in advance
Reecedjr

Id be worried about a blown headgasket. If the car has a CPO warranty, take it to a dealer before purchasing and have them look it over. My 4.8is is a monster and I love it.

Take the oil cap off and see if has, what looks like, milk on it. This could be a sign of antifreeze in your head. Either way, if it looks like this, there is moisture in your engine and something needs to be repaired.

It will look similar to this:

http://www.pelicanparts.com/BMW/techarticles/E36-Head-Gasket/pic2.jpg

Had the truck been sitting for awhile before he drove it? If so, it could be simply condensation built up in the exhaust system. This tends to happen when vehicles have been driven very little, over short distances, with large swings in external temperatures.

If you have the milky substance on the oil cap, then you have a blown head gasket or cracked head--both very unlikely for such low mileage.

My guess, however, is that the smoke is most likely a result of a plugged oil separator valve. The mileage is a little low for that to occur, but not unheard of. Check out this thread (it refers to a 6-cyl engine, but the symptoms and fix are basically the same for the 8-cyls):

white smoke (http://www.xoutpost.com/bmw-sav-forums/x5-e53-forum/44989-head-gasket-oil-separator-something-else.html?highlight=white+smoke)

my 4.8is had a similar problem, i replaced the headgasket and its all good now.