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Air Oil Separator change

noblebenn

Member
Joined
10 Jul 2018
Messages
17
Will be changing the Air Oil Separator next week, is there anything else, parts wise, anyone recommends is changed along side it or any words of advice?

Thanks
 
I had this fail on my 4S a couple of years ago- cost a fortune for what was a cheap (and pointless) bit as the engine had to be dropped.

If the engine is coming out on yours, then consider
- brake lines (as they go over the gearbox)
- clutch
- IMS, if you are minded to inspect/change
- any other leaky seals

Apparently for a C2 you can get at it without dropping the engine.
 
It's 99' C4. I think we should be able to do it with engine in place so was thinking more along the lines of clips, pipes, connections etc but if we do drop the engine then will look at the bigger items.
 
Wasz covered this on his.

You're working blind and its an utter pig. He got it done though.
If you've got a ramp it can only help. :thumb:
 
Good luck!

I still feel a burning resentment at my AOS failing... so many more interesting mods and improvements I could have spent that money on. :sad:
 
Yes Ive got a full garage with ramps available and some very handy mechanics on hand.

If I can ask, what was the cost of having a third party do the swap for you?

I work on my cars because I enjoy it but I've no problem having recognised garages doing the works. I kind of go with the thinking that if they can do it why can't I but know it's not always this simple!
 
Cost will range depending on your Indy and location etc but you're looking at the thick end of a grand easy, because an Indy will drop the whole motor out.

So definitely worth some skinned knuckles if you can do it yourself. The part is only £100.
 
Changing the AOS in situ is the equivalent of decorating your hallway through your letterbox whilst stood outside..........but it's doable :grin:
 
Good luck!

I swapped mine while I had the gearbox out, even with good access it was awkward getting the connections off the old, getting the old out and the new into position and fitting the hoses onto the new.

Mine is a '99 with 130k, I only replaced it because I heard horror stories and thought I should replace while I had access. There was oil in every port so probably the old was probably failing - that reminds me I still have it to cut open and look at the diaphragm on the old one.

The vacuum lines are a little fragile (aged rigid plastic), and the o rings inside them had hardened making them a total pig get off and then back on. The force required to pull them off whilst trying not to snap them is a lot.

I replaced the o rings after a while of struggling then when I ran the engine there was an air leak from one (identified using a home made smoke machine). The o ring had got damaged when I pushed it on (almost impossible to vget it on straight and push it in the correct plane, so I had to get in there and swap the o ring again.

The online guides make it sound easy, and it might well be if your car is a lot younger.


noblebenn said:
I work on my cars because I enjoy it

So do I but this was not much fun. I wouldn't contemplate doing it again without either A) dropping the engine or b) dropping the gearbox and having replacement rigid vacuum lines on hand.

It would be a doddle if the engine was dropped. I reckon I could do it blindfolded with the engine dropped.

If you car has never had the over gearbox brake line changed it might be worth dropping the gearbox at least. Its not that hard.
 
Thank you for the replies.

I use the car a lot and like things maintained properly so an engine drop it is. Will be good to have a look around and change other things for piece of mind.
 
My Mechanic did mine without dripping the engine. saves time & money. My total bill was less than £500

Lots of indys will tell you that you HAVE to drop the engine.
You do not.
 
Manual and in theory it can be done in situe .. Tip and it cant .

Now .. my thoughts .. ive tryed to do a few in situe over the last year or so .. these cars are not new anymore .. things just dont come undone .. pipes snap ..

You have very limited access to do it in situe .. on a new car you have a chance .. from my experience then i would say drop the engine ..

Ill put it this way .. im never attempting to do one in situe again and if the customer wants to go elswere he can .. that is how bad this job can be .

Times and its about 8 hrs to remove and refit a manual engine .. tip is something like 12 hours .

Its perfectly possible to do as a diy job .. Porsche designed these engines to come out pretty easily .. you basically have x4 bolts and a lot of pipes !

You also get to see the brake lines which are normally worth doing and the coolant pipes which are starting to show their age and corrode.

Hence my advice .. just drop it .. save your self a lot of grief and replace the pipes as needed while your there ..

You only really do this job once so get it all done in one hit .

My 2 pennys anyways .
 
Just replaced mine while engine was dropped for a rebuild. Gotta say I can only imagine it would be a nightmare if the engine wasn't out of the car. Dropping / refitting the engine was actually pretty straight forwards
 
I did mine a couple of years ago ('98 C2) and it was a horrific job. I didn't drop the engine or the gearbox and I wish I had. If it ever needs doing again then I'll be taking it to an indy. I still wake up in a cold sweat thinking about that job.
 

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