Oil Cap Air Sucking Noise

[schoir]

It's possible to replace just the rubber gasket in the oil fill cap.

Part number for 986 is 996.107.336.00.

Regards, Maurice.

[dja1980]

Thanks guys!

So when you guys have your car running and you "listen" to your oil cap, yours is silent, correct? I only ask because I just read a few other threads that say the hissing noise is supposed to be there... so now I'm really confused.

I'm now wondering if I got a CEL because the oil cap was in the half-closed position and NOT allowing air in. I left it in the fully-closed position when I discovered it half-closed last week, and the CEL since turned off.

I'll still try to pull the codes and post them here. I think we have a dry week coming up next week, so hopefully I'll have the car out again then.

[schoir]

Originally Posted by dja1980

Thanks guys!

So when you guys have your car running and you "listen" to your oil cap, yours is silent, correct? I only ask because I just read a few other threads that say the hissing noise is supposed to be there... so now I'm really confused.

I'm now wondering if I got a CEL because the oil cap was in the half-closed position and NOT allowing air in. I left it in the fully-closed position when I discovered it half-closed last week, and the CEL since turned off.

I'll still try to pull the codes and post them here. I think we have a dry week coming up next week, so hopefully I'll have the car out again then.

There is supposed to be some slight suction (and an accompanying hissing noise) there. If there is extreme suction (this is starting to sound funny ) then that is an indication that your AOS is failing. In that case, it will be very difficult to pull the oil cap off the tube.

If the oil cap was in the half-closed position, that would allow unmetered air into the system and thereby throw a CEL. If you tightened it correctly and the seal is good, then the DME will turn off the CEL after a few drive cycles because there is no longer an air leak.

Regards, Maurice.

[dja1980]

Ah, ok... that makes. Thanks for the clarification. Maybe I'll let it go for now and see what happens. As stated in my first post, when the cap was in the half-closed position, it seemed to be overly tight and there was zero noise.

Turning it fully-closed allows the cap to pop back up slightly, which I'm now thinking is the way the way Porsche designed it. Since it sounds that there IS supposed to be some slight suction noise, is it safe to assume that NO airflow through the cap could have caused the CEL?

[70Sixter]

Originally Posted by schoir

There is supposed to be some slight suction (and an accompanying hissing noise) there. If there is extreme suction (this is starting to sound funny ) then that is an indication that your AOS is failing. In that case, it will be very difficult to pull the oil cap off the tube.

Regards, Maurice.

And that could also indicate worn rings are causing blow-by.

[Boxtaboy]

Huh?! There's supposed to be a suction noise? I thought it was supposed to be a complete seal? Ok, now you guys are gonna make me open my trunk while the car is running to check if there's any noise near the oil cap. LOL.

[dja1980]

Originally Posted by Boxtaboy

Huh?! There's supposed to be a suction noise? I thought it was supposed to be a complete seal? Ok, now you guys are gonna make me open my trunk while the car is running to check if there's any noise near the oil cap. LOL.

Actually, please do... lol

I would really like to get a concrete answer on this!

[Boxtaboy]

Originally Posted by dja1980

Actually, please do... lol

I would really like to get a concrete answer on this!

Haha...ok, no prob. When I go home later today after work, I will listen for any noise, and report back!