Hey all, i have higher oil consumption and an indy mechanic mentioned crank case vent valve as he saw some oil in there. I think the oil/air separator is the crank case vent valve is that correct? I heard about the oil cap test to test the oil/air separator and i posted the video here. The cap was hard to take off but it did eventually come off. If I can get some peoples thoughts on whether they think this is an oil/air separator issue?
https://www.youtube.com/watch?v=vfwr7Cq9xyw&feature=youtu.be
thank you

 

can anyone else with a 2010 panamera s verify that it should be that difficult to remove the oil cap when idle?

 

I heard a decent size pop when you removed the cap. That is an indicator of oil separator not working right.
There should not be pressure in there, and your cap should just twist off and remove without any pressure difference.
If someone can chime in to give second opinion, would be great. Thanks.

 

yep true there was a suction noise when i finally lifted the cap off wasnt sure if that was normal or not

 

there is going to be a small pressure difference - the crankcase is under a vacuum, I just did my 2010 4S, small amount of effort to get it and you can hear the vacuum breaking when you twist it open
nothing like what you experienced.

 

thanks dogwood so given that i had a tougher struggle to get the cap off does that mean my AOS is not doing its job and oil getting sucked into the engine or could it be something else?

 

taken from the 996 forum
"The diaphragm within the separator splits and allows full intake vacuum to reach into the crankcase, in minor cases the engine runs lean and the DME adaption facility alters the fuelling to compensate and the driver may not notice anything; in the worst case scenario the intake system takes in engine oil from the crankcase and the engine can hydraulic lock on the oil (doesn't much like compressing, liquid). In between cases usually result in smoke on start-up and at idle (burning off residual oil) and general fluffy running."

this is why if your cap is hard to take off it is a pretty good sign of a failed AOS

 

more info

"Porsche Engine Oil/Air Separators 101

The Engine oil air separator directly affects the engine crankcase atmosphere because basically all Porsches from 1980 on including the current 986-987-996-997-Caymen & Cayenne engines all are positive crankcase type systems meaning the engine crankcase has vacuum supplied from the intake manifold to collect and burn the residual combustion by-products or blow-by in the crankcase by running it through the engine again, basically to lower the overall vehicle emissions.
On most occasions, when the oil separator fails, intake vacuum in the engine crankcase rises to an unusually high or abnormally high figure and more likely than not ends up drawing engine oil into the intake system usually fouling spark plugs and even possibly causing damage to the oxygen sensors (O2), catalytic convertors and even possibly various other sensitive fuel injection components.
Interestingly enough, the only way to test the oil separator is to periodically test the engine crankcase vacuum with a water filled Monometer AKA an ultrasensitive vacuum gauge. On BMW’s and Porsche’s, the engine crankcase vacuum is normally around 4-7” (Inches) of water. When these oil separators fail the crankcase vacuum can rise to 9-12” and even higher depending on the extent of the failure.
When the oil separator is starting to fail on Boxsters (986-987), generally you will start to see a substantial amount of smoke from the exhaust tailpipe. When the oil separator finally fails, the engine exhaust smoke can reach dangerous proportions that almost look like it was manufactured from an anti-mosquito smoke machine. Unusually enough, on the 999-997’s, when the oil separator fails, it hardly ever creates any exhaust tailpipe smoke, almost being like a silent killer or costly surprise.
On another note, it has been known on rare occasions, that when an oil separator fails that it is possible to have a slightly rich running condition that might turn on the check engine light or CEL. The only way to know what is happening is to check the fuel trim numbers on the OBD-II “Freeze Frame” data and crankcase vacuum to see exactly what’s going on, otherwise your just guessing.

Tony Callas"

 

thanks dogwood im thinking i may have this issue due to the vacuum suction that is going on, the ultrasensitive vacuum gauge do the porsche dealerships have such a tool?

 

I would be surprised if they didn't

 

anyone else tried to remove their oil fill cap when car is idle?

 

You have had some on here chime in about your car. They do work on cars. If you ro not trust their word, you really should take the car to a mechanic who will fix it for you.

 

oh yeah i understand, was just wondering if anyone has their own experience with the oil cap difficulties when car is at idle

 

A little pressure is expected. When you experience what you showed us on the video, there is big pressure built up in there. Indicator of AOS not working (it is supposed to prevent your engine from oily stuff getting into wrong places. When it breaks, it does not allow air flow, hence you get pressure build up. Take care of it before it costs you more than just AOS replacement, and make sure your oil is always topped up to top notch in green.
Good luck.