XuTVJet

When I bought my 2011 Cayman Base 6MT back October 2022 and thoroughly cleaned the engine bay, I noticed oil residue on a 3" section of the plastic vent line from AOS to the intake tube and also on the plastic vent line the spans the front of the engine. The AOS/intake tube vent was an easy replacement so I did that first and when I inspect the old vent line, sure enough, there was a hard to see hairline crack in the area of the residue. Which then confirmed the oil residue I saw on the front of the engine vent line also likely had a crack. Since this vent line was in a much more difficult area to access, I put some heavy duty electrical tape around the oily area of the line (cleaned it up first), hope for the best, and decided to research what I'd need to remove to get the thing out.

The front vent line in question is part No. 9A1-107-515-01 ($115) and it's the vent line that attaches to four points on the front side top of the motor. Two points are just in front of the AOS on the driver's side front side/top of the motor (connections #1 and #2), a point just below the intake manifold towards the front top middle of the motor (connection point #3), and at a point passenger side top of the motor (connection #4). This job is not easy and a lot needs to come out and a lot of care needed when getting the new line back in. Given the age of these cars, one must be very careful when moving, disconnecting things, etc.

Things that have to be disconnected and/or removed are noted below. I could have done this job a lot quicker if I did all this first. All of it is required to get the new vent line in. It's impossible to do it otherwise unless you want to bend the living crap out of the new vent line and risk breaking it.

1) Disconnect the battery
2) Remove the intake manifold assembly. It is MUCH easier to remove/install the intake manifold with the shifter cables completely out of the way.
3) The main 12V power line harness assembly needs released from it's mount just above the A/C compressor which is held on with two 10mm nuts. You need to release assembly this to get more access to get the vent line out/in as Porsche routes the line through this harness (why!?!?!?).
4) Main power line needs to be removed/unclipped from it's plastic clip/guide on the front of the engine. The shift cables runs in this guide as well. Unclipping the wire from the guide will help create more movement with the 12v wire/assembly and aid in creating more room to get the vent line out/in.
5) Disconnect the shifter cables and push them back through the firewall hole and back into the cabin. You need the cables completely out of the way as they impede careful install of the new line.
6) Remove AOS. This needs to be done to create more room for vent line access/movement on the install.

Once you have all that stuff out of the way, you can remove the old vent line. Three connection points are the difficult to squeeze press connectors with orange o-rings and the connection point is a dual O-ring press in pipe (connection #1) affixed with a E10 bolt. This dual O-ring connection is super tight into the motor. I had to use a zip tie formed into a loop wrapped around the vent to line so I could grab/twist/compel the thing to come out. In the process, I broke the vent line to connection #2 and passed the point of no return. Connection #3 was definitely leaking at the O-ring based on all the oil reside in the area and on the line. Connection #4 hardly was connected and required little effort to get out. Not much oil residue was observed in this area which seemed odd since the line didn't seem too well secured. Once I got the old vent line out, I found a tiny hairline crack in line about 2" up from the connection point. The vent line was extremely brittle after 14 years of life. I cannot imagine what Porsche would charge to do this job.

Was was very happy to see that nothing else appeared to be leaking in the area under the intake manifold. The intake manifold rubber seals were full of oil because I think the prior owners kept the oil levels too high. But otherwise, everything looked good and was a good time to clean up the area.

I took me the better part of 8 hours to do this job. I could do it now into about 3-4 hours. It's something that can't be rushed because of how tight everything is and everything that needs to be removed. If Porsche would have made the engine bay just 5% bigger, things would be much easier. It really is 10lbs of crap in a 5lb bag. Attached are pictures of the old vent line (it's broken at connection #2, see my note above). Other photos show connection #3, routing of the vent line through the 12v harness, etc.

The real kicker though is I notice no change in driveability so the vacuum leaks must have been insignificant. LOL. But, I do have comfort that there's a new line there and the risk a major crack is low now.

jesseellington

Wow, I just had to install this line on my 08 987.1 in order to install the ultimate AOS upgrade. Much easier as only the end connections. Very fiddly getting stuff routed across the area under the plenum. I had that removed but a bunch of stuff in there. Newer cars are certainly never simpler.

Zirconocene

I understand why Porsche did this the way they did but I sure with they had used parts that were a bit more user-serviceable. Like, for example, if you had the ability to just replace that single portion of that hose assembly.

Thanks for documenting this, I'm sure that as these cars age, that hard plastic is going to do owners no favors.

Cheers