Well, traditionally high crankcase pressure on turbo cars can cause oil smoke. High crankcase pressure can prevent oil from draining from the turbo, so the oil gets pushed past the piston ring seals on the turbo shaft. The oil can go into both the exhaust and intake sides. Also, if you're air oil separator is busted, that's another source and that's connected to that compressor inlet tube on the passenger side turbo. So you're doing a few WOTs which creates a lot of crankcase pressure, the oil makes it's way into the intake side of things. There's lots of places for oil to pool on the intake side like the intercoolers, so the next time you crank up the car, lots of oil smoke burning off all that pooled oil in the IC pipes and intercooler.

 

I recorded the oil level as being 50% and falling again, presumably because oil is once again being consumed.

I am going to perform some wot throttle events this morning on the way to the office and once parked will try to pull the oil filler cap off and see if there is big vacuum holding the cap down.

Hopefully this will help assist in the diagnosis of the oil separator for the dealer.

For my benefit and better knowledge, what should I be requesting from the dealer as preventative maintenance or other repairs related to all this engine oil being consumed?

New plugs?
Cleaning of the air intake system?
Cleaning if the inter oilers?
Can you clean the cats?

I plan to keep the car and don't want the oil residue to further other damage.

Beyond that, I must rely on the dealer for the rest.

I will update the thread later today.

 

Oil filler cap was tougher to remove following wot pills than when cold started in the morning.

Oil level has fall as well...

 

Honestly, with your level of oil burn, I think the piston rings may be shot leading to the excessive crank case pressure. In my opinion, it's outside the norm. I think they need to do a crank case pressure check and cylinder leak down check. There's a slight chance your turbos are shot, so they need to check the shaft play. If the bearings on your turbos were excessively worn, you would also get excessive oil burn because the turbo shafts would have excessive play and generate more clearance for the oil to get by. But considering your level of burn, I think the turbos would have self destructed by now.

 

Car is currently in for an air/ oil separator replacement.

 

I would ask for a cylinder leak down check too. I saw Vektor Performance was testing an auxiliary air oil separator. Don't know how far along in development they are.

 

Any update?

 

Hey! Thanks for following up.

The car car went in last week Thursday to star the process of replacing the air/ oil separator, upon further review the techs discovered the issue to be the check valve for the supply/ return lines to the turbos. No longer is the cause to the engine smoke the a/o separator.

There was also signs oil in the clear vacuum lines behind the air filter box.

The supply/ return oil lines to the turbos have recently been updated and parts only arrived today. Repair should start tomorrow or monday.

...update to follow next week.

 

Nice, sounds like unique issue for sure

 

This sounds like a PCV system issue for sure. If the backflow valve in the passenger side intake, internal OEM Air Oil Separator, or manifold check (PCV) valve are faulty or intermittently faulty ,then it can suck oil into your engine depending on load/conditions. These kinds of issues are often difficult to pinpoint and more often misdiagnosed as turbo seals or overfilling.

If you start to remove intake tract part, you will be able to diagnose where exactly the oil is coming from. I would be surprised if it were engine internals unless a LOT of oil was ingested, the car is VERY modified, or there's a bad tune/gas being used. I suppose there is always the option of a oil retaining ring put in incorrectly at the factory, which can also cause odd smoking issues, but that is extremely rare.

 

Supply/ return turbo oil lines removed and replaced with new last week, had the car back out for some high load pulls on the highway. Once parked the car once again started smoking on start up following a 2 hour rest.

The car car has been returned to Porsche for a full refund.... just kidding...

It has now been determined that the car must be brought back into the dealership in preparation for one or both turbos to be replaced.

 

Honestly, I only give it a 1% chance the turbos are the issue. They are just chasing their tail at the dealership. The don't have to remove the turbos, they can check the radial and axial play of the shaft to see if they are in spec. I give it 98% that you have excessive crank case pressure from too much blow-by. Too much crank case pressure prevents the oil from draining from the turbos properly, so the oil goes out the next least path of resistance being the piston rings seals on the shafts of the turbo on the compressor and turbine sides. So I believe the issue is with the piston rings on the pistons which seem to not have broken in properly. They could determine this by doing a leak down check.If they leak down comes out good, then sure, go ahead and do the turbos. But I wouldn't touch the turbos until after doing a leak down. And also checking the shaft play of the turbos before taking them off and replacing. It doesn't sound like they've done any real trouble shooting. Instead, just throwing new parts at the car hoping it fixes the issue.

 

The dealership has told me that they are taking the their direction from Germany on this case. The information you have provided above is very helpful and may or may not be the case, I have however been requesting the same testing from the dealer simply because it is good advise (especially to help speed up the repair process).

As with many brands I don’t think that the dealership takes direction from the customer unless the customer wants to pay for the “additional” requested work. The dealer confirmed that additional testing like a leak down test would be chargeable, which is fine, while the car is under warrantee it is important to allow the manufacturer the right time to investigate the issue st their expense.

A friend end of mine pointed me to this thread which appears to be the similar issue: https://www.pistonheads.com/gassing/...&t=1652670&p=2

the turbo replacement solved the same issues I am having with my car in the thread link above.

An update post repair will be provided to benefit the members of the forum.

 

There is a youtube video by Nick Murray that shows his 991.2 having so many issues (electrical gremlins) that Porsche NA did buy the car back from him. I know you were joking, but it has been done previously.

 

There are check valves in the intake manifold, AOS, and turbo drains that all need to work 100% correctly. If one (or more) of those has a manufactured defect, assembly debris, or was assembled incorrectly it certainly will smoke and cause intermittent smoking issues. My money is on a <$200 part causing the problem.