Re: 80k (13000 Kilometers) Original AOS,should I change out?

I am up in Canada,car still in storage but coming out soon hopefully! As above I now have 130000 kilometres and was wondering if its worth being
proactive in changing out the air oil separator .I have not had any indication to any problems, just occasional white smoke out the tail pipe for couple minutes
on cold start up or if I am parked on an incline.No difficulty removing the oil cap ect.This is the original unit in the car.I had the air intake off to replace a starter
last fall and there was a a light film of oil on the inside but definitely not dripping,Throttle body looked clean. I have read some scary posts on some that have had it go
and ended up changing out the Cats,plugs sensors ect eat.Whats your thoughts on this subject? Thx

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moresquirt
I am up in Canada,car still in storage but coming out soon hopefully! As above I now have 130000 kilometres and was wondering if its worth being
proactive in changing out the air oil separator .I have not had any indication to any problems, just occasional white smoke out the tail pipe for couple minutes
on cold start up or if I am parked on an incline.No difficulty removing the oil cap ect.This is the original unit in the car.I had the air intake off to replace a starter
last fall and there was a a light film of oil on the inside but definitely not dripping,Throttle body looked clean. I have read some scary posts on some that have had it go
and ended up changing out the Cats,plugs sensors ect eat.Whats your thoughts on this subject? Thx

My 2002 is on its 3rd replacement AOS. They last anywhere from around 80K miles to over 100K miles. The first time I over reacted I think and had the service department replace the plugs. The 2nd and 3rd time I didn't bother. The plugs and anything else that might have been affected by the oil vapor from a failing AOS will lose the oil from the heat. So I just drove the car around town to make sure everything was ok then hit the highway. The 2nd time I drove all the way home to CA from MO. 2K miles.

The AOS on your car's engine is at the 80K mile mark. If you would not be upset by the possibility you could be replacing an AOS that has possibly another 20K to maybe 40K miles left replace the AOS.

Thx for reply MarcW. I only put approx 6-7k on a year so thats a lot of possible years left if I am fortunate enough.
I have seen posts on some making a squealing noise and others with just Hugh amounts of smoke out the tail pipe that won't quit.
If and when mine decides to blow or if the diaphragm gets a small tear is the smoke white or blue .
Thx

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moresquirt
Thx for reply MarcW. I only put approx 6-7k on a year so thats a lot of possible years left if I am fortunate enough.
I have seen posts on some making a squealing noise and others with just Hugh amounts of smoke out the tail pipe that won't quit.
If and when mine decides to blow or if the diaphragm gets a small tear is the smoke white or blue .
Thx

Low mielage cars appear to experience shorter AOS life which if this is the case your car's AOS is living on borrowed time. Really the minute a new AOS is installed and enters service it is on borrowed time, but in your car's case with 80K miles it is even more so.

You have to be careful assuming the AOS will fail with the same symptoms as others have reported.

Kind of funny, and a bit odd too, but all 3 of the AOS's in my car failed with different symptoms. The first one started out with just a bit of hesitation off idle kind of like a engine in need of plugs and points maybe. After not too much run time the engine idle started to go up and down. Not lots but it was quite obvious something was wrong because up to this point the idle had been very stable.

After I spent some time messing around -- and discovering I could not remove the oil tube filler cap due to the pressure difference -- and an oily throttle body and oil at the hose connection that I learned later was the hose from the MAF -- and still not knowing what was wrong -- this was back in early 2004 when AOS failure was rather new but I had covered almost 80K miles in the car in just 2+ years of ownership -- the engine starting smoking. I called the dealer SM and he told me "AOS" and to have the car flat bedded in, which I did.

The 2nd AOS things were just fine as I was driving from CA to MO. But at the end of every day's drive sitting at a light after just pulling off the freeway the CEL would come on concurrent with the engine giving just a hint of a stumble in its otherwise smooth and consistent idle. I can't recall the error codes now but they probably indicated a lean condition and the DME having reached its limit as to how much fuel it could add. For some reason I suspected the MAF and felt I could drive on and if necessary disconnect the MAF if it failed outright and limp to where I could get a replacement MAF. But I made it to my destination without any more drama other than the CEL towards the end of the day's drive. But after 3 days of driving and reaching my destination and checking into a hotel the next morning upon first start the engine just billowed smoke and I knew then what was going on. Like before I arranged to have the car flat bedded to the as it turned out the same dealer that did the first AOS.

The 3rd time I got no warning something was up. The car was fine, symptom free, until on the way to visit my Mom and Dad and driving on surface streets I took off from a stop light and as usual glanced in the rear view mirror and saw a cloud of what later proved to be oil smoke but at the time I suspected water/coolant vapor. But the dash gages/warning lights gave no indication of anything wrong and after a block or less of driving I realized what was going on and turned around to drive the car 10 miles to the dealer.

Made it a mile or so but got caught at a long light and the engine started smoking again -- it had stopped not too long after I pulled away from the stop light -- and the engine was running rough. I sought out a parking lot with lots of room and pulled the car in and parked it so the flat bed could get at the car with ease and called the auto club for a tow truck. Probably just as well. I had dodged the bigger bullet of engine lock up two times before by opting to tow the car in vs. drive it.

Three AOS failures and the only common symptom is billowing smoke and this is at the end when the failure has progressed to just short of the point the engine probably wouldn't run much longer and worse if it does is at the risk of suffering hydraulic lock due to the amount of oil that the engine is ingesting. (The 1st time the SM stressed not to continue to drive the car. He had another car in like mine -- same color in fact -- that suffered an AOS failure but the owner insisted on continuing to drive the car -- IIRC awaiting the arrival of the parts -- and the engine locked up.)

Ok u got my attention! I ordered one for replacement.Thx for all the info.

UPDATE: I installed a new AOS few days ago, went pretty smooth.I decided to cut open the old (Original AOS) and see if any rips or pin holes ect after 80000 miles.(130000 Kilometres )
I did not see any pin holes or rips BUT the Diaphragm was definitely on it last legs.I gently pulled on the rubber to see how much stretch or flex was left
and it immediately ripped.The rubber was obviously dry rotted and it would not have been much longer before it came apart.I would say in the next 10000 miles maybe.
After reading up on what mileage most are getting out of there AOS (not tracked) I would say between 80 and 100k is a fair guess as to when they go based on what I have personally found.
Probably length of time has a bearing also.This AOS was on my 2006 Boxster.I feel its worth changing this part out due to the possible issues that you could encounter when it goes.FYI