Hi Scotty, I have a ‘99 GMC Yukon SLE with a Vortec 5.7 Ltr V8 SFI engine. Has 182,465 miles. I live in Southern California.

I recently had 3 head cylinders replaced that were bad.  Since then, I noticed that white exhaust coming out of the tailpipe if the engine is sitting with the engine idling for more than 3-4 minutes.

 Has never done that before. I’ve been waiting to get it smogged, but I’m not sure if it’s going to pass. 

Previous work done on the Yukon several years prior, I had the transmission rebuilt, new radiator replaced, rotors and drums replaced. Mechanically there has been no other work done.

It does leak oil, but a simple fix I’m sure. It runs great aside from it smoking when it idles.  I get about 13mpg city and 17-19 mpg hwy still.

Do you know what’s causing the engine to put out white smoke when it idles?

I’ve gone back to my mechanic twice to resolve this problem, but it still happens. I love my Yukon and it serves its purpose and don’t want to get rid of it even though it’s a gas hog.

With all the problems with cars that are on the market, it’s cheaper for me to keep my Yukon. I drive an average of 5,000 miles a year and only really fill up the tank once every 5-8 weeks.