Dilberto

Every time I return from a Mountain biking trip - the CTT smokes like somebody poured a can of Seafoam directly into the intake. The smoke bomb lasts only for 3-5 seconds. It never does this when I drive hard on the freeway. Only on winding, up-down mountainous terrain. I've changed:

1) Air Oil Separator
2) PCV Check Valve
3) Lower breather hose(by Serp tension pulley)
4) Lower Intercooler pressure hose 0-rings(x2)

Honestly, its pissing me off to no end. My oil consumption is still outside what is considered normal(1.6q every 800 miles) and I'm out of solutions. What say ye?

Porschetech3

Check the hoses for oil coming from the vacuum pump that is located on the passenger side head on the rear, it's driven by the camshaft. I have seen oil get in these hoses and usually causes a failure of the exhaust PSE changeover valves or the fuel tank leak detection pump fails from oil intrusion, but the oil could also puddle up in the intake and spill into a intake port on curvy maneuvers..If you find oil there you would need to replace the vacuum pump and clean all the lines and intake. Hope this helps..

deilenberger

Is the smoke mostly on downhill stretches? That sort of symptom is common for bad valve guide seals. Under downhill sections with some engine braking - there is a high vacuum in the cylinders - which can suck oil past the valve guides if the seals are worn.

Dilberto

Yes, I engine brake on downhill sections. I'm going to cease this habit today. Every time I get smoke episodes... P0421 and p0341 cat inefficiency codes appear. Both downstream 02s tested good. Its not until I clear and avoid winding descents does the codes remain off.

Petza914

Have you periodically drained the accumulated oil from the driver's side intercooler. There's a vent line that feeds into the intake here for emissions purposes to send oil vapor back through the motor, but the vapor condenses here and becomes actual oil which is maybe being sucked into the motor during engine braking and the high vacuum condition it creates.

Dilberto

You got my attention now. Are you referring to the silver canister near the coolant tank?

J'sWorld

I am assuming you replaced this check valve #13 with the lower PCV hose?



Due to the design of the Cayenne cylinder heads, the height at which the valve seals sit in relation to the spring seat where the oil would puddle, and the extreme draining capability of the heads I don't think that your valve seals are to blame. .

J'sWorld

# 15 here is what Petza was referring to.



It feeds/attaches to # 4 here. The metered air coming into the turbo inlet here provides vacuum to the crankcase/pcv in which case that air has already been metered and accounted for but is somewhat inert.
This is why the drivers side intercooler hose is normally full of oil while the pass. is not.

Dilberto

Mr. Haney, so you are saying the #2 two way valve on top of the throttle body is allowing oil vapor into the intake?

J'sWorld

Yes, but because of my uncertainty of the mode of actuation and my innability to find more info on all of the above I need to get back home to my stuff and look at everything to say positively how this can happen. Because it would be a major boost leak if normally open I would say it is normally closed.

Porschetech3

I misread your year model, I was thinking of the problems with the 08+ Turbo's, they have a mechanical vacuum pump on the back of the head that leaks oil into the vacuum system. Your 06 models Turbo do suffer from the oil accumulation in the turbo hose on the drivers side right at the front of the turbo as others have stated, from the crankcase vent system.

Dilberto

Both pipes smoke, after the mountain drives. I'm thinking something is allowing oil vapor or just oil itself into the intake. I usually idle the car for 5min after those winding drives. No change...

Petza914

Have you pulled the driver's side intercooler to see how much oil is accumulated in it? Has this ever been done? Those who don't know about the vent line into the intake track here see oil in the intercooler and think it's blow-by from a bad turbo, but it's not. It should be emptied every other oil change or so. If it's full enough that it's introducing oil into the intake air flow during aggressive curves, it's also not doing it's job as an intercooler very well.

Dilberto

I cleaned the driver side boost hose recently. I also removed and thoroughly cleaned intake manifold pressure sensor part number 948.605.137 D3 which is some kind of ECU sensor, resting on top of the throttle port Mr. Haney was talking about. Keep it coming, gents!

nodoors

I think we covered the basics. It seems to me that replication is important to narrow it down and figure out if your leak is exacerbated by lateral G's or high vacuum and rpm.

I would try to figure out if it is the engine braking, hard cornering or the combination of the two. You have stated in the past that this thing is guzzling oil, so you might as well get to the bottom of it before your cats are destroyed.

1. Try driving around town using an obscene amount of engine braking and higher rpms than you normally would by using manual mode.
2. Find a hill where you can drive your car off camber on each side for a bit to see if that will generate the smoke.

My guess is that #1 will make it smoke and am with Don on this one thinking it is likely worn valve guide seals since you have address the other known issues of check valve, AOS, and draining the driver's intercooler hose.