AOS check

I checked my AOS with a manometer and it is reading ~10.8 inH2O. I have read the ideal value should be 5 inH20. I assume i need to replace my AOS. How urgently should i replace it and could this reading indicate something else.

Nope u have a bad aos and needs replaced. It will only get worse. How much worse with what effect.... its a gamble on a 20k rebuild if u flood the head with oil and hydrolock the motor. Point being is u have a known issue in a very expensive motor, it could be just fine for a long time or not? Get yourself a uaos unit and dont have an issue again.

Thank you. Ill order one and install it.

They r a pita to install and the uaos fixes that. Just an unrealiable part that needs an upgrade.

You Tube

Dont want the above to happen...I was going over some of the instructions. While I'm replacing the AOS it looks like i might as well replace the injectors since they haven't been replaced (35k miles)? Anything else i should check or replace while I'm in there?

There's a similar thread going on right now with ideas: https://rennlist.com/forums/996-foru...r-project.html I did this last winterUAOSInjectors replace vacuum lines (some will break) Replace the starter/alternator Y cable? (It corrodes badly at the starter)Anything else you see "while you're in there"

Thank you everyone for the feedback. I have ordered the UAOS, fuel injectors and some vacuum lines. Ill probably tackle this project week after next assuming everything comes in. Should be fun. Ill be relying on all the great info on this site as it dive in.

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Where did you find the injectors? I looked a few weeks ago and it seemed they weren't available.

Auto Atlanta Porsche as another member suggested.

I just did my AOS and it wasn't as bad as described. I have found working on these engines to be a little intimidating, but not that bad once I get into it. There is a lot to learn as Porsche does think differently, but now that I've done it once it makes a lot more sense. I went with the stock AOS and not the UAOS because of price. Will I replace it again? Yes, in another 80K miles. If FCPEuro is still around they will replace the parts under warranty which is where I bought the parts. A challenging job, but not as bad as described on the internet. i would strongly encourage you to replace the vacuum system, or as much of it as possible while you are there. Often overlooked, it is just plastic hose, and rubber elbows and splitters, with a couple of switches and a directional valve. Not expensive either. And the tank, all those plastic pieces are 20 years old and have baked in heat every time the car runs. Best,

Thank you for the encouragement Euroguy911. Im looking forward to the project. I did order some vacuum lines but not sure what other bits to order. Ill look up a diagram of the vacuum system and order the other bits. Im on the fence with the expansion tank. It looks in good shape from what I can see, no yellowing but it is 18 years old now.

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I can tell from your post that you are handy with a wrench and are mechanically inclined.And I agree with every thing you said here. The only thing I will add is that you are new here and don't know all the history of the AOS. It has a bad reputation of failing in short order and even the Genuine Porsche units have many cases of failing right out of the box. That's why most top shops recommend replacement every 3 years, but it's not so much the cost of the AOS, but the cost of the labor and PITA of replacement and the incurred risk of Hydrolock.if it fails quickly and completely. I know talking about it could be considered as fear-mongering, but I have seen many engines replaced under warranty by Porsche, and many after warranty for AOS failures. I have worked in Dealerships for over 45 years and in Domestic and Japanese also and I can't think of any other instances of such frequent failure with dire consequences, although most AOS failures in m96 do not result in Hydrolock.

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LOL! All sounds good until you discover your brand new AOS failed 6 months later and you have to do it all over again. Small hands and skinny arms come in handy, I have neither!