smoke on start up
Will this be a problem in the future, or is it just something you can live with?
Trending Topics
the tires are about to go, this smoke problem, the rear door creaks in cold temperatures, the water pump has not been changed, nor the timing belt (im at 105,xxx miles), the rain sensing wipers decide to go on whenever they want, I cant put a CD in slot 6 because I got an error one time and Im afraid it will happen again, and im pretty sure the tranny is about to go soon. haha
Celebrating Lexus & Toyota from Around the Globe

Last edited by mmarshall; Jan 25, 2010 at 02:49 PM.
This particular situation arises when the engine is shut down and oil begins to ooze between the valve guide and the valve stem, puddling maybe a drop on top of the closed valves until the system is depressured and oil drains back to the pan. When the engine is started after several hours, that "leaked" oil provides quick lubrication before oil can be circulated up to the head, but the tiny portion sitting on top of the valve is burned in the cylinder immediately - accounting for the blue-white puff of smoke.
I've had Chevrolet (and GM) people tell me that their production choice was to leave the valve guides a little soft on the assumption that the puff of white smoke on startup was a better choice than a tight seal that would wear away the valve stem, especially before the oil pump reached full pressure to lubricate the top end.
That may sound like an excuse, but because valve guide leakage goes back to the 327 and 283 CID GM engines of the late 50's, they have certainly had plenty of time to solve it in the past 50 years if they wanted to. I suspect that the Toyota/Lexus engineers may have made the same engineering decision. For those bothered by the white smoke, the aftermarket offers plenty of replacement guides that won't leak.














