Help! still smoking after AOS replacement - 986 Forum - The Community for Porsche Boxster & Cayman Owners

A few years ago I had a AOS go bad. I almost had a heart attack when I saw the massive smoke plume coming from my exhaust. So I did not freak out last month when Smoke came billowing out.. I figured AOS issue again. I ordered parts and replaced. But the smoke is still coming out! Oil smoke definite burning oil smell. Any suggestions? Comments? I would post video but new to this and not sure how. But Trust me this is Thick billowing Cant see the back of the car from 10 feet way type stuff

might be residue that is burning off. are you sure there isn't a leak in one of the hoses? have you tried the "oil cap suction" test?

Unless it is a broken oil filler tube or vent tube it's still residue. this stuff lays in the intake. you should have taken the intake apart ( yes it's a pain) and cleaned it thouroghly. the residue will stay in there for a long time.

Agreed. I just did the AOS replacement and when I took the intake apart it was covered in oil and started spilling out. Probably about 2 tablespoons of oil pooled up in there. Needs a thorough cleaning for sure.

Believe it or not I just took a friends intake apart - failed AOS and IMS and there are "pockets" just before the tubes turn down that hold a lot of oil more than spoon fulls. I think I took half a cup out of there both sides plus the throttle body was soaked in oil.

There is also the possibility that your replacement AOS is bad. That apparently happens more often than you would imagine.Tthe suction test mentioned above should tell you if that is the problem.

thanks for the tips. I am going to try to clean the intake system today. I heard that it is supposed to be harder to remove oil cap if aos is bad but not sure how much vacuum there is normal. For the suggestions about the oil filler tube i was wondering the best way to test this. i was thinking of taking the filler tube loose where it enters the engine near the aos. If I clamp a heavy plastic bag over the engine end of the tube would that work to test theory?

I took apart the intake from the throttle body to the top of the intake manifold. There was so much oil in there I could not believe it. I cleaned out every thing I could reach. I used a whole roll of paper towels to soak it up. When I loosened the clamps on the tubes connecting the manifolds oil ran out all over the top of the engine. When i reached into the top of the manifold the paper towel i was using came out dripping. I reassembled and it was still smoking really bad. If my understanding of the boxster engine is correct The three tubes ftom the intake manifold go straight to the where the intake valves are located. Is there a possibility I have a big puddle of oil sitting on top of the intake valves? Do I need to take the Intake manifold loose from the engine and clean out chamber above valves? I was thinking abour getting a piece of clear aquarium tubing and fishing on end down the manifold and see if i can suck up any oil. Any ideas would be appreciated.

There isn't any place for oil to sit beyond where you found it but there will be a lot of residue on the walls of the intake tubes.I usually take the down pipes off as well (yes they are a pain in the a**) and wash them down with brake cleaner then dry them and reinstall. If you got most of the oil out from the top then it should clear up, however I have heard of stories where the cats filled up with oil and the keep burning for a while until they are burned off. Of course the other problem could be, as was mention by Mark, that your replacement AOS is bad. It has happened on several occasion that I'm aware of.

Finally got a day off to work on this again. back on april 15th I took the intake system from throttle body to the intake manifold apart. I took a rag attached to a wire and swabbed out each tube from the top to the bottom. Today I reassembled it. To test the AOS I took the top hose that runs from AOS to the intake loose. I rubber banded a plastic bag over the AOS tube and plugged the hole in the intake. Cranked her up and the bag inflated with fumes and no oil came from AOS into the bag. It did not smoke much at first just the normal flat six startup. but after a minute or so (time enough for catalytic converter to heat up) lots of smoke. I found out someone trying to help me fix the car was trying to bypass AOS and attached a hose in its place and ran the engine for a minute or so. so...... No telling how much oil was pumped into the cylinders. Harryrcb had said something about catalytic converter filling up and causing major smoke. So if Harryrcb is right and the cats are full what are best options. My father-in-law says drill a small hole and see if any oil leaks out , flush the cats with someting and jb weld the hole shut. I know correct answer is take it apart but short on time and money. any ideasappreciated espescially fast cheap and easy ones?

Just went out and cranked it up again. No smoke at all at first. So I let it idle. after 9 minutes it started smoking but not like it was before.

It will burn off in time....

Your #2 cylinder sparkplug is probably oil fouled. Passenger side middle cyl. check it, replace if needed & check #1 & #3 if #2 was bad then get on the hwy & burn out the rest of the oil. Just be aware if the smoke gets worse shut off the engine. The engine can Hydrolock if enough oil gets in a cylinder & bend a connecting rod, but I think you are safe unless the AOS starts dumping oil again.

I just replace the AOS and plugs. it was really only smoking on high revs under load. after replacing the AOS is ran well and did not smoke, after driving it around easy for a while, I got on it a few times. shortly afterwards I noticed the the idle was a little high. checked for a vacuum leak and saw that I had damaged the oil filler tube while I was fighting with the AOS. took it off and fixed it, and put it back on. when I started it up again it was smoking like crazy and running rough. Tomorrow I will drive it around a little to see if it clears ups. if not, I have no idea.

Mine did it one or two more times within a week of replacing AOS. That was at the beginning of last summer and it hasn't done it again since.

Quotes source post: 400986

thanks, mine did it a bit on start up this morning, but was done by the time I got a mile down the road. didn't do it at lunch and is running great. hopefully that is the last of it cause these think are a RPITA to work on