** This is posted in the 944 Turbo/Turbo S section also, but just in case someone might see it here - I wanted to cross post. Sorry if you ran across it in both places... **

Just a bit of background, if you haven't seen some of my other threads about my coolant loss, overheating, seeping cam tower gasket, etc. in the past. basically, i had coolant loss from the reservoir on a regular basis, overheating symptoms, a cam tower gasket that was leaking onto the headers, a leaking ps rack and various other small issues. so the slippery slope began, the teardown commenced and pretty much everything accessible was replaced, unless it showed to be in great shape. i had assumed the seals on the oil filter housing had let go and were allowing for a mild mixture, but i never saw any oil in my coolant. when i pulled the water pump, there seemed to be a minimal milkshake residue in there. when i pulled the lines to the oil cooler, all coolant and oil came out separately and clean. so, i seemed to still be chasing my coolant loss issue. all new seals/gaskets were replaced on the housing, cam tower, with water pump and all hoses to go.

i'm still piecing everything back together and, even though i had the AOS hoses and seals, i considered skipping that procedure just based on how much of a pita the removal looked of the AOS. in the end, i decided i was going to at least replacement the small, upper elbow hose - at the top of the AOS - and check to see how things looked. i'm guessing now, based on the pics below, i have bad seals on the AOS and need to pull everything to reseal it. am i correct, based on what the pics show, that i more than likely have leaking seals on the AOS?

if so, i'd appreciate any hints on how to perform this removal/install with the least frustration and/or need for mass quantities of alcohol. the black bracket in front of and curving towards the AOS - does that have to come out and is there a 3rd bolt at the bottom? i assume it won't slide out with just the top 2 bolts removed - that would be way too easy for a 951. can the AOS actually be pulled with the brake booster heat shield in place? my car was up on jacks for quite a while, but it's back on the ground now - soon to go back up - but i can't get a good look-see underneath right now.

when i pull the AOS, can this be cleaned similar to say the remote oil cooler? can it be flushed of gunk and reused or am i looking at a new AOS? i would appreciate any help any of you are willing to give. i know many have gone through this and your insight would be extremely welcomed.

thanks very much.

 

I've only attempted this with the engine out, turbo off, on the way to doing the balance shaft seals (which btw are often leakers). Most of the pain I've managed to flush from memory but managed to get after the clutch, RMS, pan gasket and a qucik check of #2 rod while I was in there. Once we has the AOS out we found that it had heat damage (melted). Sorry can't remember many details about the bolts other than they were irritating....Bruce

 

When I removed mine, I found that the black bracket has a rolled edge at the bottom, which stopped me just sliding it up and out. I remember reading about people grinding the edge off while still on the car but access looked tough to me. The bolt that holds the exhaust to the black bracket and heatshield is really hard to access, I had to grind down a small socket and use it with a wobble extension, then switch to a regular wrench.

I already had the crossover pipe removed, so I removed the turbo which made access somewhat easier. I also had the brake booster heat shield removed.

The AOS does have three bolts, one is right at the bottom.

When the AOS is off though, it is possible to clean it but there are a couple of caveats. The top is held on with clips (they could be brittle so take care when opening it) and is sealed with an O ring. The O ring isn't available from porsche so you need to find a similar one. I ordered one from theoringstore.com which I am hoping will be a close enough match.

Once you remove the top cap though, the whole thing is just hollow. No baffles - just a big empty cannister. I'm in the process of cleaning mine up with a set of bottle brushes. The oil residue is really caked on there.

I'm also told that getting this all back together can be tough, as you have to line up the holes in the heat shield, black bracket, and exhaust simultaneously so you can feed that bolt back through them.

 

i was thinking about it last night and how much clearance would it have really taken for the AOS to be teetered - top and bottom - so that the o-rings could be replaced by simply removing the AOS bolts? why not change the shape from round to oval and gain some clearance that way. it's practically impossible to replace with the engine in - with the turbo, downpipe, bracket, etc. still in place.