DIY Porsche Motorsports AOS Install 987.1

I wanted to post a DIY on installing the porsche motorsports AOS , part number 98710792600. I could not find a DIY for this install anywhere on the forum. All the old articles/links are broken, so here we go! Parts needed: 987 107 926 00 - 987.1 Motorsports AOS 987 107 947 00 - Vent Line from crankcase to AOS 987 107 946 00 - Y hose from intake plenum to AOS 900 067 316 02 - 6mm x 35mm bolts (need two) I'll go over some quick tips about removing the old AOS and why the intake plenum needs to be removed to replace the large vent line, then cover the motorsports AOS install. Before starting, I suggest you take your car out for a rip to get it nice and warm. Park it where you'll be executing the replacement, and let it cool back down for an hour or two before you start. You'll thank me later. Stock dusty starting point: Removing the stock AOS. The AOS drain engine side clamp I was able to easily get to from the top. Right hand, set of regular pliers held reversed in my hand, and just went down to get it off. Very easy for me. To get to the right bolt at the AOS, you have to pull this wire harness out of the way. Pull on the harness enough to get the socket on and no more. Stock AOS compared to the motorsports AOS. In this picture you can see why new (longer) AOS bolts are needed, as the mounting feet of the motorsports AOS are taller than the OEM ones. At this point I slid the motorsports AOS into the engine bay where it goes but did not bolt it in. The AOS drain line slides right onto the block, and in my case, I reused my AOS drain line with clamps because it was all still in great shape. Of note, I pre-installed the drain line onto the motorsports AOS and eyeballed the angle before sliding the motorsports AOS into the bay. Also pictured, test fitting the motorsports AOS y-pipe to make sure the AOS position was correct. Replacing the Vent Line. Moving to the forward end of the engine bay on the left side, we can see where the vent line connects to the crank case. Just like the other lines, it's a two pinch and pull operation to get this separated, but visibility is nil. I was able to reach in with my hand, feel down to the connection and disconnect it without much fuss. From the crankcase, the stock vent line goes under the left intake manifold, underneath the intake plenum, then snakes around to the far right of the engine bay to the stock AOS. The intake plenum needs to be removed to access the stock p-clip that holds the stock AOS vent line, pictured here. Remove the four worm gear clamps on the intake plenum t-pipe, and the single worm gear clamp on the airbox, and with some effort you can get the intake plenum out far enough to get to the p-clip, pictured here, still attached to the vent pipe. P-clip removed: Getting the old vent line out from under the intake manifold was a bit of a struggle, but not too bad. If the engine was warmed up recently (as suggested earlier) the vent pipe will be somewhat flexible, but it was still a struggle for me. Once you get the new AOS vent line snaked back in under the intake manifold and connected to the crank case, you can reinstall the intake plenum. The p-clip is not reused, as the motorsports AOS vent line is much shorter, and a straight shot. New vent line shown here under the plenum: Once the vent line is installed, you can see it points directly where it needs to even when not clicked in to the AOS: Finishing up. At this point I bolted the AOS down with the new longer bolts. I elected to use some loctite 242 (blue) on the bolts as the new bolts from porsche didn't have any preapplied. The bolts are small (6mm), so I hand-tightened with a wrench to what I was comfortable with. After bolting down the AOS, I got the clamp for the drain line reinstalled. Next is a picture showing my technique for getting the AOS drain line clamp off from the top. It honestly went pretty easily for me. Click in the y-pipe and vent line to the AOS, and you're done. Overall, a little fiddly to get the intake plenum off and replace the vent line, but not a bad job. Happy wrenching!

Thanks for this post! Is the Motorsports AOS more reliable? If so, I may do mine. In my 15 years of ownership I have been stranded just once, and it was because of the AOS going south. I did hear a strange noise for the last hour or 2 before the failure, but that was all the warning I got.

Lots of people make this job too hard. Thanks for posting a super clear procedure with lots of pics!

I'm not sure if the motorsports AOS is more reliable, but it is definitely larger, which is better for track use (my intended use). I bought this unit used with three track days and a couple of weeks of DD duty from another P9 member, so I suppose I'll see how long it lasts.

Thanks for the great post!

AOS has been an ongoing problem since I had my 2000 BS. I remember my tech says how difficult doing the install was on my 2006 CS.

It's not super difficult. People make it harder than it needs to be imo.

Quoted from the for sale thread I bought the aos from. Have any more details on this? I've searched a lot but have not found details on implementation.