Exhaust smoke from vents.

[seymore]

Hi guys, Ive had this problem for a while now. I have exhaust coming into the cabin. It really only happens between 4k and 6k rpm and when coming to a stop it will come in as well. I have taken it to a P-car mechanic and he said he "cleaned out the HE with a soap and water solution". It didn't smoke for a while after that. but if it sits for a week or so it starts again. Anyone know why its doing it or how to clean it out? Any help would be amazing. Thanks

[seymore]

Another thing this started happening after I switched to ssi. They have no rust.

[petrolblue83911]

if it's related to the HE- then it's from an oil leak hitting the top of one or both HE's as opposed to an exhaust leak.

The ways to fix it would be;

1. Find an fix the oil leak(s)
2. inspect the HE- if they are rusty/have holes then they may need to be replaced

Once you get oil into the HE- common on our cars!- it is hard to get rid of it aside from letting it burn off.

one way to tell which side is leaking is to open the HE individually- from the cockpit levers, try one, see if you get smell, if so, close it, and try the other one.

Note- if you get smell all the time from oil in the HE, (or if you get heat all the time!) then check under the car to see if the cables that open and close the duct are working properly because they can get rusted in place

good luck!!

[seymore]

It comes from the dash vents mostly from driver side and when I hit 4500rpm it fills the whole cabin. Its a LOT of smoke. I happens if the levers are up or down. and the ssi were new a year ago. so no rust.

[seymore]

Also heat works as it should. Down no heat, up a lot of heat.

[kimlangley7]

I had a similiar malfunction - it was the oil sensor on top of the engine - it was leaking - the oil dropped onto the heat exchangers > smoke and then injested into the air intakes

[wayner]

Does it mainly happen when cornering? If so this supports the oil drip theory (a pool from a slow leak spilling onto the heat exchanger).

If instead it happens all the time but only at a specific RPM, then maybe a slow leak at idle, becomes a really fast one at speed?

[seymore]

happens when going straight... and there is no smoke coming from engine bay when stopped. Its like it is trapped somewhere and released when I hit a high rpm.

[Andy911sc]

Sounds like a small leak in the actually exhaust manifold. SSI's are stainless, so I wouldn't chalk this up to corrosion but to a crack or manufacturing defect. Hense why under load at a higher rpm you get more smoke versus idling. If it was oil, it would burn off and go away. I have a small oil drip on mine and don't have any problems with smoke, unless my car sits for a few months and the oil pools. I am highly leaning on a crack or defect in the actual manifold under the heat exchange housing.

[darrenhall]

Do you have smoke coming out of the tailpipe? Or do you have smoke coming out of the tail pipe when you hit 4500 RPM+ ., If you do not , it is not a manifold issue. This is very common. You must have oil leaking onto, or into the HE. It is common that an oil leak will run down the exhaust manifold and pool inside of the HE. One reason you may be experiencing more smoke at higher RPM is the simple fact that your cooling fan is spinning at a higher RPM and foring more air/smoke into the cabin. I would bet that your HE are fine . But I would also bet you have an oil leak , And instead of oil hitting the ground it is running into your HE. i would take a few small pieces of card board and slide them between the Motor and HE and let the car set for a few days. then pull the card board out and see if there is any oil on them. If so this will help pin point where the oil is coming from. Once you have fixed the oil leak. The oil will burn off or out of the HE after a few long drives.

I hope this helps.

Cheers,

Darren E Hall

[JJ 911SC]

Originally Posted by seymore

Another thing this started happening after I switched to ssi. They have no rust.

BTDT

It start right away after I put my SSIs on 2 years ago.

If you are dripping oil on them it will make its way in the air chamber of the SSI and at on point when its hot enough it will flash over.

I pressure test them and while the exhaust path does not leak the air one does, especially where the 3 tubes enter the air section.

You can see oil at the bottom of mine. I was leaking from the lower covers...

Quote:Originally Posted by JJ 911SC

That is what I tough my problem was until I removed the SSIs yesterday.

I found a puddle of oil at the bottom of of the passenger side H.E.

The oil at the top is dripping (from within the H.E.) when the engine was upside down.

I got all kind of dripping (major) on top of it from my lower valve cover (I switched to silicone gasket and obviously did not tight them down enough).

It look like the oil got in there where the three pipe exit the "air chamber".

The exhaust pipping is dry.

[seymore]

Darren I will try the cardboard. Thanks for the tip.
No smoke out of the tail pipe except for the normal puff when you hit the gas.
Im going to take it for a long ride this weekend to try to burn it off

[seymore]

I just took my car for a good drive got it up to temp. I was trying to make a video but its hard to see the smoke with the sun. This is the best I can get. This is light smoke compared to other times. Smoke starts around 9sec from left vent... (At least I think it is coming from the vent).

Smoking Porsche - YouTube

[Racerbvd]

New Pope???

Come on, someone had to do it

[wayner]

Racerbvd, he didn't mention what colour the smoke was

As for the left vent, my friend's 72 with SSIs lets our a big puff into the cabin through the left vent the first time through a right hand turn. After that it is ok for a while.

He has a slight oil leak.

[seymore]

White smoke.

[Norm Faustino]

Byron, you read my mind and beat me to the joke. Good one man.

[seymore]

Good one guys!.... Cough... cough... wheez... wheez...as smoke fills my cabin.

[JJ 911SC]

Originally Posted by seymore

White smoke.

That would be condensation...

Mine was not a small amount. Big cloud of black smoke, good thing I got a cab.

I think I got all my leaks fix (lower covers and leaking oil thermostat just in front of the right rear wheel that was following the hose).

If you got leak around those 3 pipes, when you park the car, the dripping will find its way inside the HE.

[seymore]

JJ, Besides the obvious of fixing the leak and letting the oil burn off. Do you know how to flush out the oil in the HE? Im going to be driving everyday so it shouldn't build back up.