Advice on AOS replacement job

[Ntracing777]

Hey guys, this is cross-posted on rennlist, but I thought this might be a better venue for this questions. Apologies for any overlap.

So I'm about to dig in and replace my AOS. I know it's not for the faint of heart, but I feel I can tackle it.

My question is, what else should I replace while in that deep in? I'd rather not make return visits to this part of the engine bay in the near future if it can be avoided (that place is like my in-laws). I really want to get a comprehensive parts order in before I take the car apart. I am already planning on replacing the parts for the Secondary Air Injection check valve fault as I'd like that light to go away.

Any advice is appreciated, thanks again!

-Brock

[Loren]

:welcome:

Start by having a look at the DIY Tutorial here

[xmac]

I followed the tutorial and it worked well. The hardest part for me was removal and reinstallation of the alternator. Take your time because you will have to remove, unclip, disconnect quite a few parts lines, hoses to get to the AOS using this procedure. You don't want leaks in the intake after putting it back together. Take pictures as you do the work and make sure you put the check valves in the correct orientation. There are some small diameter hard plastic lines that go into the large rubber sleeves connecting the upper intake parts. They can break or people forget to put them back in. This is not an easy or quick job, I did it over the course of a 3 day weekend.

Don't take the following list as necessary, but I replaced:

- the oil filler tube 996.107.150.61 and ~$50

- newer model oil filler cap

- newer dipstick with double o-ring seal

- the small diameter coolant lines that go to the top of the AOS

- the o-rings for the flex/ribbed lines that connect to the AOS

- the large diameter rubber sleeves that connect the upper intake sections

- new hose clamps that tighten the large rubber sleeves

- throttle body to intake tee gasket

- I replaced the oil/water heat exchanger and the orings (I noticed there was seepage of coolant when I removed the upper intake and replaced the heat exchanger due to corrosion on the mating surface)

- new serpentine belt

- air filter

- small vacuum lines going to the check valves

- replaced the fixed pulley on the alternator with the newer free-wheeling type

While in there I did the following :

-checked that the nuts holding the cables to the starter were tight

-checked for any cracked hoses

-checked for any frayed wires (especially the knock sensor cables)

-cleaned all of the oil/residue inside the upper intake

-cleaned the throttle body

-vacuumed the top of the engine to remove grass/dirt/leaves that had accumulated (make sure the lower intake runners are covered up to protecting from flying debris)

Since I had done it before, I did not include:

- water pump/thermostat replacement

- coolant reservoir replacement

- fuel filter (much easier to get to on C4's with the left upper intake removed, C2's have the fuel filter underneath the car)