Smoke on Startup

[Stokes2500]

Good Afternoon,

My base Cayman is periodically belching a giant cloud of oil smoke at startup. My shop tested vacuum on the oil system and determined the diaphragm on the crankcase device was torn and replaced it. Unfortunately, it is still smoking on startup but it is intermittent. The shop has not been able to replicate the problem. Any suggestions?

Stokes

[Ronpor]

I would suggest you take the car on a 50 mile drive at a reasonable pace. This should burn out any condensation etc built up in the exhaust system.

[JackDidley]

My 08 S does that sometimes . If I just back out of the garage and shut it down, next time I start it I get a big puff of smoke. If I drive it a mile before I shut it down, it never smokes.

[pdxfj]

Yup.. My '07 base does the same thing. I've replaced the AOS twice, and all the associated hoses, cleaned the plenum and intake runners. Crankcase vacuum is good, etc.

Hadn't had the engine cover off in a while and when I checked PS fluid level before departing on a 3,200+ mile road trip I noticed oil seepage around plenum and intake joints again.

I guess oil vapor getting by and collecting in the intake is a fact of life. From what I've seen on other boards, people have installed catch cans, and it's quite surprising how much oil they caught after just a few hundred miles.

Have seen a number of other people report that switching to 5w-50 solved their smoke on startup issues. So I'll give it a try on my next oil change.

[tcora]

Originally Posted by JackDidley

My 08 S does that sometimes . If I just back out of the garage and shut it down, next time I start it I get a big puff of smoke. If I drive it a mile before I shut it down, it never smokes.

Same here. I figure that, at 170k miles, the valve guide seals just aren’t as good as they once were.

[Stokes2500]

I noticed for the first time that there was a large amount of condensation at the exhaust tips the last time it smogged out. The fact the the shop claimed to not be able replicate it is puzzling since it have had it happen sometimes and many as 3 or 4 times a day. I will check the plenum and intake joints to see if there is any seepage there.

[tcora]

Originally Posted by Stokes2500

I noticed for the first time that there was a large amount of condensation at the exhaust tips the last time it smogged out. The fact the the shop claimed to not be able replicate it is puzzling since it have had it happen sometimes and many as 3 or 4 times a day. I will check the plenum and intake joints to see if there is any seepage there.

That’s a head scratcher. When you wrote (above) “diaphragm on the crankcase device” I assume you mean the Air Oil Separator (AOS). One possibility is that the new one is defective, although the fact that this is intermittent seems to contradict that thought.

Your statement that you see smoke, at times, 3 or 4 times a day - can you expand on that a bit? Are these very short drives? I use my Boxster as a daily driver (when I’m not in a COVID lockdown), and rarely do I start it 4 times a day.

[Stokes2500]

Yeah, it is a DD but I alternate with my Alpina so it could sit a week. 4 times a day isnt too tough: go to work, go to lunch, come back from lunch, go to gym after, go home = 5. It is strange that it could go a day or two without smoking but will at morning startup, maybe not at mid day, but will 4 hours later when I go home.

[tonythetarga]

I know this may sound basic, but check the oil level. It is easily overfilled and any spirited cornering will slosh a bit and get sucked into the intake side. Being one bar below the arrow is about 300 or 400 ml’s only. No need to fill to the line.
Plus, standard detergent oils foam a bit and combined with higher filling, will give you that major smoke billow on start up.

[pdxfj]

FWIW, I keep the oil level in my car at the second bar from the bottom. It didn't drop at all during the road trip I did. Car still smokes on startup now and then. I've given up trying to fight it and just live with it. Will have to make cleaning out the plenum and intake runners an annual maintenance item.

[BYprodriver]

Before turning the engine off allow it to idle for at least a minute to let max amount of oil to return to oil sump.