kancell10

Hi guys,

Relatively new to 996 and completely hopeless with mechanicals and engine components but keen to learn.

According to a local garage, it seems my AOS is leaking at the top around an area with three hoses/pipes. It seems it's quite a mess so needs cleaned up before any further diagnosis can be completed. There have been no oil deposits on my drive or any white/blue smoke issues, so I'm hopeful this is either minor or new.

I'm awaiting more information, but just wanted to check if there are any usual suspects that this could be? I've read about an o-ring failing and hoses/pipes perishing.

If anyone had a picture of an AOS with the function and fluid contained within each hose/pipe that would also be ace.

I'm hopeful that if it is something minor like an o-ring or hose/pipe that access can be gained to replace relatively simply?

Thanks,

Kevin

yelcab

There are two main versions of AOS and you did not post your model year so no one here can really tell. Regardless of which version you have, changing the AOS can be a tough job to a really bitch of a job. There is no easy oring failure and the hoses / pipes are not ever easily accessed.

kancell10

Hi, great point it's a 2001 (Y plate UK) 996.1.

Having done some reading it doesn't display any symptoms (white smoke on start up) of a failed AOS, so I'm hopeful it's an o-ring or hose/pipe perishing. Sounds like even if it could be that there may me a few hours labour to do any remedial work?

hardtailer

Search for a video on YT by fcp euro (parts seller in USA) on the replacement of the AOS. That should give you the insight you want.

kancell10

That was excellent thank you, i never thought of YT. Unfortunately seems like a real pain in the *** job to do anything around the AOS. I'm unsure if you have to go to that level of disassembly for a hose/pipe replacement but understand better that it's not a 10 min job to fit a new hose/pipe.

kancell10

​​​​​​Hi guys, just to check, is this oily hose indeed one that goes to/from the AOS, before I go looking too deep into replacing the AOS and hoses? Thanks

DBJoe996

Probably not the hose, but the AOS breather valve located there.
See #6 and 7 in this parts diagram http://www.autoatlanta.com/porsche-p...section=104-10

kancell10

Ah right, so there's potential for the leak to be coming from the other end of the hose at the AOS breather valve instead of the AOS itself. The mystery thickens! I'll try get my hand in and clean that hose up as best I can and keep an eye on it. I'm at the point where I'm trying to decide whether to get the garage to strip it all and replace the AOS and all pipes, or understand if a simple tightening or replacement of an o-ring from the top is all that is required.

yelcab

That is not going to happen.

De Jeeper

The first thing u should do is test the aos. All it takes in a manometer, an old oil cap with a fitting and 15 seconds. Tons of threads on this. Determine if its still good or see if u have to replace the entire thing. If so consider the uaos as an upgrade. Lots of threads on the uaos.

If its the cross over hose it can be broken in several spots. It get brittle from the engine heat. It takes a fair amount of work to replace the cross over hose and even if the aos was good i would replace it with the uaos unit if going through the trouble of getting to it.