Big Smoky Mystery

[regiment1]

So here's a random one for you guys.

My LS got a new (reman) motor in 2005. Since then, on three occasions, I have gotten a big cloud of white smoke out of the tailpipes when I start the car. This is usually after the car has been driven a short distance, say a mile or so, and left to sit for about 90 minutes to two hours. The smoke clears immediately and there is no problem otherwise.

This has happened three times in 6 years. It's just weird to me.

 

[joegr]

I've discussed this issue with two other guys. So far, there is no proven cause. Here are my two theories.

1. You have a bad spot on at least one valve stem. When you happen to stop the engine at just the right spot, oil leaks down the valve stem into that cylinder.

2. Your oil return passages are a little clogged on one bank. If you are at just the right angle, oil backs up and gets sucked into the PCV system.

Both guys I've talked with don't think that it is either of those two possibilities, but that's all I can think of.

 

[regiment1]

Interesting. Would the valve stem issue be affected by the engine temp? I think it's not getting all the way up to normal temperature due to the short drive. Logically a seal might expand a little more under full temp and make a better seal.

 

[msgtusmc]

White smoke is usually associated with moisture. Blue smoke with oil. If it is only white smoke, not white then blue, I would suspect moisture, water vapor. Improper torque procedures in installing heads can cause leaking water from water jackets. I would pull the valve covers, use a torque wrench & check head bolt torque according with normal torque procedures. Head gasket replacement maybe required.

 

[joegr]

White smoke is usually associated with moisture. Blue smoke with oil. If it is only white smoke, not white then blue, I would suspect moisture, water vapor. Improper torque procedures in installing heads can cause leaking water from water jackets. I would pull the valve covers, use a torque wrench & check head bolt torque according with normal torque procedures. Head gasket replacement maybe required.

Keep in mind that synthetic oil seems to result in pretty much white smoke out of the tailpipe (after the converter).