Car gurus...

[Pacfanweb]

Originally posted by: Zenmervolt

Originally posted by: Zim Hosein

Originally posted by: Zenmervolt

Originally posted by: Zim Hosein
The wrong oil viscosity and worn rings can cause white smoke upon startup, that would go away when the engine reaches "normal" temp.

No, oil thins as it heats. Even though the viscosity number increases for multi-weight oil, it is still thinner once it's hot. If the rings are going, it will smoke more than just at start-up. And again, the smoke will not be white, it will be blue-grey.

ZV

Correct, but the worn rings expand under the heat.

Not enough to seal.

ZV

Try changine oil when the car is cold, then when it's hot and tell me it doesn't thin. Of course it's thinner. The viscosity is still within spec, but it's definitely thinner.

 

[FrustratedUser]

Originally posted by: Eli
If it goes away, it's just condensation in the exhaust.

No worries here.

Burning oil is blue-grey.

 

[Pacfanweb]

As someone already mentioned, Eli, I think, it is normal for any car to put out white clouds of condensation on cold starts. This is due to the catalyst process mostly, as it produces water, and also is worse in more humid climates.

If it goes away after a few miles it is completely normal.

If it doesn't, then smell it. If it is sort of a sweet smell, that's antifreeze burning....and that ain't good.

Oil smoke is generally blueish. Gas smoke can either be black or white, depending on how rich it is.

 

[Pacfanweb]

Originally posted by: Zim Hosein

Originally posted by: Zenmervolt

Originally posted by: Zim Hosein

Originally posted by: Zenmervolt

Originally posted by: Zim Hosein
The wrong oil viscosity and worn rings can cause white smoke upon startup, that would go away when the engine reaches "normal" temp.

No, oil thins as it heats. Even though the viscosity number increases for multi-weight oil, it is still thinner once it's hot. If the rings are going, it will smoke more than just at start-up. And again, the smoke will not be white, it will be blue-grey.

ZV

Correct, but the worn rings expand under the heat.

Not enough to seal.

ZV

Depends on the wear IMO.

ALL rings expand when hot. That's why there is a gap when cold, so it doesn't touch when it expands.
And Zim is correct in certain circumstances. Worn rings don't always smoke all the time. I've seen hundreds of cars that only smoked under a heavy load, such as taking off from a stop light, and the rings were the problem.
Also seen cars with worn rings that only smoked when you downshifted the car to slow down. They were fine under accel, but turned into mosquito killers if you downshifted.

Then you have the ones that just smoke all the time. And there are some with worn rings that never noticeably smoke...they just use too much oil.
Ford used to have that problem in the 80's with the 5.0's....they actually told people that one quart every 500 miles was acceptable consumption. Then they had a TSB for higher-tension rings to fix it, but it cost a bit of horsepower.

It really just depends.

 

[Eli]

Originally posted by: Pacfanweb

Originally posted by: Zim Hosein

Originally posted by: Zenmervolt

Originally posted by: Zim Hosein

Originally posted by: Zenmervolt

Originally posted by: Zim Hosein
The wrong oil viscosity and worn rings can cause white smoke upon startup, that would go away when the engine reaches "normal" temp.

No, oil thins as it heats. Even though the viscosity number increases for multi-weight oil, it is still thinner once it's hot. If the rings are going, it will smoke more than just at start-up. And again, the smoke will not be white, it will be blue-grey.

ZV

Correct, but the worn rings expand under the heat.

Not enough to seal.

ZV

Depends on the wear IMO.

ALL rings expand when hot. That's why there is a gap when cold, so it doesn't touch when it expands.
And Zim is correct in certain circumstances. Worn rings don't always smoke all the time. I've seen hundreds of cars that only smoked under a heavy load, such as taking off from a stop light, and the rings were the problem.
Also seen cars with worn rings that only smoked when you downshifted the car to slow down. They were fine under accel, but turned into mosquito killers if you downshifted.

Then you have the ones that just smoke all the time. And there are some with worn rings that never noticeably smoke...they just use too much oil.
Ford used to have that problem in the 80's with the 5.0's....they actually told people that one quart every 500 miles was acceptable consumption. Then they had a TSB for higher-tension rings to fix it, but it cost a bit of horsepower.

It really just depends.

Yeah, absolutely. But in those cases it's not completely gone, it just depends on the circumstances. 😉

If he could get it to smoke while accelerating, decelerating, etc... then our advice would be different. But if it's just some white smoke at startup, and only sometimes... it's most likely condensation and nothing to worry about.

The term "smoke" is used losely.

 

[Pacfanweb]

Originally posted by: Eli
If he could get it to smoke while accelerating, decelerating, etc... then our advice would be different. But if it's just some white smoke at startup, and only sometimes... it's most likely condensation and nothing to worry about.

Yep, pretty much my opinion, too.

Amazing how many customers over the years I've had complain about normal condensation from the exhaust in the morning.

Also had lots of them think that the condensation from the A/C drain was something wrong, too. "I've had the car 2 years and I swear it's never done that before".
Me: "Sir/Ma'am, we're in North Carolina, it's 98 degrees and 90% humidity...if your A/C isn't leaking it isn't working properly."