Smoke while warming up, from what???

[SeattleChris]

Purchased a 964 C4 back in January. Car is in great condition with records back to '93. Only has 87k miles. PPI came up very clean except for the rear swing plate bushings (damn those bushings are expensive?!?) and a very minor leak on a valve cover.

I drove the car once delivered about 1,000 miles with zero smoke on start and warm up. I took the car to have the oil changed and valves adjusted to get a maintenance baseline for my own records moving forward. My local mechanic, John Walker (who is an acclaimed PNW air-cooled mechanic dating back to the 60s) adjusted the valves, changed the oil, and inspected the car. Everything came back great (except for the swing plate bushings) and he praised the condition of the car. He intentionally filled the oil tank low, like you're supposed to.

About 200 miles into the fresh oil change and valve adjustment, the car began to smoke from the tail pipe. The smoke doesn't show until about 30-45 seconds after startup and seems to continue until the car is warm. I haven't noticed it too much once the car is hot, but it's also been at night when it's more difficult to see (it's dark quite often up here). The smoke doesn't smell like the typical exhaust smell on a cold day (like in the photo below). For the most part, I've only been doing around town driving (less than 20-30 miles, 2 or 3 days/week). It isn't the classic oil leak 1 plume of smoke once started up, it seems different. There is a lot of moisture here in the PNW that could be steaming off, but it wouldn't be constant?

Anyone have any ideas? Checking the oil right after an oil change has proven difficult. Clean oil on a dipstick is very difficult to see and my oil gauge seems to always be in the red with the occasional (after a long drive) coming up to 4 or 3 o'clock. The gauge range hasn't changed pre or post valve adjustment/oil change. I'm very hesitant to put more/too much oil into it, but I imagine oil is burning somewhere. Would driving the car only around town be the culprit? In reality, the car is only really at a warm temperature (temp gauge at 8 o'clock) for 10-20 minutes each drive, could that be it? Do I need to get it warm for 30+ minutes?

Any input or advice would be appreciated!



Chris

[ossiblue]

Here are the clues:

The smoke doesn't show until about 30-45 seconds after startup and seems to continue until the car is warm.

I've only been doing around town driving (less than 20-30 miles, 2 or 3 days/week).

There is a lot of moisture here in the PNW.

the car is only really at a warm temperature (temp gauge at 8 o'clock) for 10-20 minutes each drive.

Given your mechanic (JW) and the other factors you describe, added to the clues, above, I'm betting you're seeing moisture from the crankcase/oil tank. It's very typical for water vapor to be seen early on in a cold start, and last a bit longer in situations like yours. The boiling off of water in the oil will take a bit of time at high temps. Your driving pattern doesn't seem to be enough to fully get rid of the moisture which is collecting in the oil tank. Take the car out for a good, long drive at freeway speed and you'll likely see the "smoke" appear early, and disappear, completely, shortly thereafter.

[edragg4]

+1.. My 81 SC use to do the same thing. When I drove it short distances and tucked it away for days. Started driving her longer to get it heated up and the problem disappeared.

[yelcab1]

you live in the PNW, where the air is full of humidity. That air is sucked into the engine and the water is burnet off into steam. In addition, a by product of organic combustion is H2O, and that too is burnt off into steam.

That steam shows up as white vapor on the exhaust port. Normal. Drive it more.

[pmax]

Also sounds like you are warming up the car by idling it for 30-45 secs.

That's too long.

[virob]

I'm also in the PNW. The white steam is normal. I only take the Porsche out if I can drive it at least 30 min at operating temp at speed to get the moisture out before putting it back in the garage. I live about 6 miles from work, so it is not a daily driver. I don't think the car (any car for that matter) likes the short drives, especially city drives.

[SeattleChris]

Thanks for the feedback. It seems like all of the symptoms align with just shorter drives around town and vapor. I thought the same thing at first, but was a little concerned with how long the smoke came out and that smoke isn't white, it's almost blue in color. Is that typical of Vapor? It has a different scent as well, not the normal of exhaust. Does that align with water vapor?

I'm planning to stretch her legs this weekend, hopefully that clears it up!

[yelcab1]

Blue is not water.

[Joe Bob]

If it sits for awhile.....it will smoke at start up. Drive it like a rental.

[twistoffat]

Check the inside of the oil filler cap for moisture build up(yellow gunk). If its there you need to drive it more at the others have said to burn off the moisture.

[DRACO A5OG]

+1 Drive Off immediately, our cars do not need to be warmed up just keep her under 3500 RPMs for the first 10 minutes, verify with PAG owner's manual it will say something very similar.

White/Grey smoke is vapor. Do not worry about it and try to take her for a long drive to burn off the moisture. After this start her, she should be nice and clear on start up.

[scarceller]

Does it only smoke while at idle? Does it get worse while driving during decel?

If only at idle and just for a few minutes I agree with others that most likely not an issue.
You could pull a plug from each cyl to see what they look like.

[Thomas Owen]

Where do you park it at night - inside or outside? Sure sounds like moisture to me, but most importantly, what does John say about this? If it is a phenomena of that area with a 911 I am sure he has seen it...

[crg53]

You could have a power steering fluid leak, or a leak from the power steering drive. Either of these will leak fluid down onto the right hand side heat exchanger, that then will start smoking in around 20-30 sec after start up. Check part # 5 & 6 in the picture HERE .

[OsoMoore]

Originally Posted by ossiblue

Here are the clues:

The smoke doesn't show until about 30-45 seconds after startup and seems to continue until the car is warm.

I've only been doing around town driving (less than 20-30 miles, 2 or 3 days/week).

There is a lot of moisture here in the PNW.

the car is only really at a warm temperature (temp gauge at 8 o'clock) for 10-20 minutes each drive.

Given your mechanic (JW) and the other factors you describe, added to the clues, above, I'm betting you're seeing moisture from the crankcase/oil tank. It's very typical for water vapor to be seen early on in a cold start, and last a bit longer in situations like yours. The boiling off of water in the oil will take a bit of time at high temps. Your driving pattern doesn't seem to be enough to fully get rid of the moisture which is collecting in the oil tank. Take the car out for a good, long drive at freeway speed and you'll likely see the "smoke" appear early, and disappear, completely, shortly thereafter.

Take the long way home! My commute is just 4.5 miles, so I like to pick up my wife and hit the back roads for an hour, at least once a week.