rhkwon

I’m going to tackle my water pump, coolant expansion tank and coolant hoses and so also decided to replace the AOS.

I know the AOS has several hoses attached to it. Not sure if these are coolant , oil and vacuum hoses. Just want to replace everything that is attached because I’m sure these parts are also old and brittle.

Does anyone know which parts to replace and would replacing these be difficult? Any parts names and or numbers along with any tips would be great. I’m feeling a bit intimidated by the AOS procedure but while I have everything apart want to replace everything that could fail later because I don’t want to do this again for a long time.

Car is a 1999 C4 manual.

dporto

Since you've got '99 it's probably a good idea to do your fuel filter as well (just behind expansion tank and in front/over of the AOS). I hope you're lowering the engine a few inches at least...

DBJoe996

Replacing the hoses is probably a good idea, but I would say it would depend on the mileage. You will need new intake runner gaskets. The AOS to Bank 2 hose is a PITA to route and replace. Only replace with a Porsche AOS because you never want to go in there again.

808Bill

I'm doing mine this week! I can't imagine replacing the AOS plumbing with the motor in and I'm not going to
Damn! https://www.ecstuning.com/b-genuine-porsche-parts/rubber-intake-manifold-gasket-priced-each/99711024702/?msclkid=8da9b10fda771d25284eedc8fb76ae28&utm_source=bing&utm_medium=cpc &utm_campaign=Srch.US.ProductAds(BSC)&utm_term=4579809528315249&utm_cont ent=All%20Productstry...

rhkwon

The car has 132K on it.

rhkwon

The intake gaskets for sure.

I assume the Bank 1 hose would be much easier with the engine out or when a new clutch is being put in?

So forget the vacuum hose. What about the coolant hoses?

rhkwon

i am beginning to be in complete agreement with you on this.

DGI

I was going to drop my motor this coming winter to tackle all these jobs at once as well. Looking forward to hearing about your process and any tips/tricks you learn along the way.