Smoke on startup


On today’s show (9/15) someone had acar that blew a puff os smoke for 30secs or so on startup. The answer was basically “some cars do that.” It’s been a long time since I did much on cars, but I always understood that a small amount of smoke on startup, but not once you were driving, and no oil consumption, was a sign of worn valve lifter seals. Maybe modern cars are different.


I think you mean valve stem seals, and yes I agree, that can be a sign of stem seal failure on some cars.

However, some cars do, do that. Late 60s - early 70s BMW were specifically designed to allow small oil drainage to extend engine life.


I had a 1984 Chevy Impala 305 which did the same, small puff of smoke on startup, then clean exhaust. We drove this car to almost 300,000 miles, and it never got worse. Oil consumption at this mileage was only 1 quart every 1500 miles. If, when you lift your foot off the gas pedal and see a lot of smoke in the rearview mirror, your valves guides are sufficiently worn that you need new ones. At that stage the car will also consume a lot of oil.


Years ago my 90 Camry 4 used to do this. Once, when I started it in a parking lot, my friends said it looked like the car was on fire from a distance. At the time I considered the leaking valve guide theory. The smoke always cleared right away. The car now has 206K, and I don’t notice it doing it so much. My idea was that it’s because I finally had the air cleaner changed. I guessed that on startup the fuel injection didn’t have enough information about the mixture and took a second to adjust. Bogus?

My theory is no good for a 1984 Chevy. Therefore, I will be interested to see what other people say about this.


Scudder, yep, that’s right valve stem seals. Told you it had been a while.

So you’re saying that those Beamers were just glorified 2-strokes?

We also believed that all British cars (and bikes) also were designed to leak oil on purpose to avoid rust on the frame - or at least they worked that way.


What color was the smoke?


I had similar problem with my 95 Camry. It was still under warranty (by a week) when Toyota reworked the valve guides and completely resolved the poblem.