Bozbomber

I notice there is a heavy smoke when I start up my 02 996. This only appear when it first start. I don't drive the car often, like once a week or two and it currently have 69k miles on it. I wonder if this is normal?

russo

Nothing to worry about if the smoke is white.

Macster

Does the engine smoke every startup? Or just every once in a while? How is oil level?

Side note: I've been running my Boxster's oil level down to just a few bars over minimum for weeks now. Finally decided to add oil and added enough to bring the level up to one bar below maximum. Wouldn't you know a few starts after I did this I saw engine oil smoke upon start up the first episode in I can't even begin to count engine starts.

If the engine smokes every time and the oil level's good the AOS could be going out. Any other engine symptoms? Mildly hunting idle speed? A bit flat off idle? Rough running? I assume check engine light works and has not come on?

Engines that don't get run often or don't get run long enough to get up to temperature are a bit more likely to smoke upon startup. Also, running the oil level high and "high" can vary a bit from engine to engine, can also contribute to an engine's propensity to smoke upon startup.

Also, if the oil's got miles on it it has likely collected more water and unburned fuel. This doesn't get boiled away cause engine doesn't get hot very often and these fluids lower the oil's viscosity. They also raise the oil level. They also help deplete the anti-foaming additive package of the oil. Thus the oil foams more and put more oil vapor into the crankcase. This overwhelms the AOS (air/oil separator) and more oil fumes get routed to the intake manifold. While engine is running you won't notice any smoke, but this oil gets deposited on the intake walls. When you shut off the engine the oil drains down the walls and into one or more intake runners and if the intake valves open will drain into the combustion chamber. If the valves closed the oil will puddle on top of the closed intake valves.

Upon the next engine start oil smoke is the result.

Drive the car more. Keep oil fresh and at the proper level. Try to get the engine nice and hot once in a while. You don't have to race across town do to this. Just drive on a mild day. If you can leave AC off cause if this on it causes electric radiator fans to come on which keeps coolant cooler and indirectly the oil runs cooler too. Cool enough it may not get hot eough (212F) to boil away the water.

If engine starts running rough, if CEL comes on, if smoking lasts longer than just a moment at start up get car checked out pronto for a bad AOS.

Sincerely,

Macster.

Bozbomber

Thanks guys! The smokes coming out from the exhaust are white smokes. I just recently had an oil change at the outside shop with mobil 0-40w oil so the oil level is at max. level. The ideal is is stable and no check engine light is on.

I start the car every few days as I don't drive the car much. I am just curious because I don't remember seeing the smoke when i first purchased the car.

Thanks!

xel996

Hey Bozbomber, can we see PICS of your car? hehehe

Bozbomber

Picture of the car only or with the white smoke?

Here is the picture of the car after wash.

soverystout

Looks alot like my 03.

Has anyone conisdered that this may be the o rings in the spark plug tubes?

If you have pulled your plugs and some of them have oil on them, that is the culprit.

Oil seeps into the combustion area and on start up, it is burned off.

Macster

Just starting the engine and letting it idle a while without driving the car long enough to get the engine and oil up to full temperature can exacrebate the smoking symptom.

This drenches the interior of the engine -- mainly the underside of the pistons and cylinders -- with oil.

The engine has oil jets which spray a large amount of oil directly at the underside of each piston for cooling (can reduce piston crown temp by 50C) and lubrication of the piston, rings, small rod end bearing and piston pin, and the cylinder walls. The downside is if the engine shut off "cold" there's a lot of oil that can seep past the rings and into the combustion chambers. The result is the engine more likely to smoke at next startup.

If you drive the engine until it is hot and the oil hot -- which can take some time these engines have a lot of coolant and oil to warm up and around 400+ pounds of aluminum, steel, and iron which is the engine to warm up -- then before you shut off the engine you let it idle a moment or two the hot oil will more readily flow away from the pistons and away from the combustion chambers. If the engine not parked on level ground, of course the oil will flow downhill. If car parked on a side slope the oil will flow away from the chambers on one side of the engine but the oil on the pistons and cylinders of the other bank will flow towards the chambers of those cylinders.

Letting the engine idle a moment or two also gives time to let the engine internals shed excessive oil that they accumulated when the engine was running faster. Unless the oil very hot, and oil pressure low, the piston oil jets are still directing a lot of oil at the piston bottoms but this still results in the least amount of oil to possibly make it into the chambers.

Still, when the engine is started the smoking should be just a brief cloud at startup and should not continue. If after a minute of idling -- and a minute is a huge amount of time in this situation -- if the engine is still smoking that's not normal engine behavior. If while you're driving the car the engine continues to smoke, or smokes at various times, that's not normal.

I think you should seek some assurance from a professional technican qualified to work on these cars the smoking is not a sign of pending troubles. AOS comes to mind.

Sincerely,

Macster.

Translog

Bozbomber,

I have had the same thing happen but at DEW, when running hard on a hot day at the track. If I come in and do not let the car idle and settle down in temp and just turn it off, I can usually get smoke from the exhaust a large puff that goes away. Apparently its oil getting past the rings due to expansion form heat. I would assume that if you leave your car sit for a period of time with topped up levels that some oil will and could seep threw as well. But from all accounts, professionals at the track with a lot of mechanical experience nothing to worry about. I certainly freaked out the first time.Hope this helps.

Pierre

Bozbomber

Thanks Translog! This white smoke coming out from the exhaust only appeared when I first start up the car. The white smoke doesn't appear for the rest of the day if I shut off the car and restart or after drive around.

Topaz330ci

Do you park on a even surface or on a slope?

jumper5836

You sure there isn't a tint of blue in the smoke?

Bozbomber

Parked inside the garage with a even surface.

Bozbomber

A tint of blue in the smoke? Not that I notice tho.... Let me get a photo and post up this weekend. I usually start up the car once a week.

pjl

This happened to me off and on for a couple of months, i.e, white/blueish billowing smoke out of the exhaust on startup after (typically) a spirited run that would eventually clear out. Then one time I noticed it was still smoking (out of the exhaust) while I was driving it. The engine started seizing up and it was curtains. The engine had to be taken apart and rebuilt. This was an '02 engine with 97K miles on it.

Not saying that's going to happen to anyone else, but that was my experience. And no, a cause was never diagnosed.