Air/Oil Seperator write up? - Page 3 - 986 Forum - The Community for Porsche Boxster & Cayman Owners

Brad Roberts · 10-07-2008, 04:12 PM

This was a customers car

I lightly "fanned" it with brake clean to help break up the dust/dirt on top then hit it with ZEP, then wiped it down. DO NOT spray a direct stream of brake clean at the plenum, it will discolor the black. You CAN shoot the brake clean directly at the top and bottom of the engine. Just be sure to put something down to catch it as it rolls off the sides. It will leave a ton of CRAP on your garage floor or driveway. I use cardboard.

If you ever have to take it in to somebody for work, they will greatly appreciate the fact that you made an *attempt* at keeping it clean. Promise.

B

fasterjames · 12-23-2008, 08:22 AM

Great write up on the AOS. While removing the lower breather hose (not the accordian one) from the AOS I broke the clamp not realizing it is actually part of the hose! Now that the AOS is back in I cannot trace the hose to where it ends.

Is this a hose that I can replace somewhat easily if I remove the AOS?
Is there another fix for this clamp where I wouldn't need to replace the hose? It seems a daunting task.

Thanks!

kellysplanet · 03-29-2009, 07:18 PM

I noticed that the main sign of this part going bad was pulling the oil cap while running. I tried it after the swap and my car almost died the idle went so low. I could also hear a loud hissing "air suction noise" coming from the part. Did I crack a hose or no lock it in properly? Have any of you heard this? I am afraid to drive it until I can figure if it is done correctly. At least I found the cause of my major oil leak when I swapped this part, I hope that was it, loll. If anybody could give me a sign that it’s okay the noise is normal and the idle drop is normal, it be greatly appreciated.

Viper5 · 03-30-2009, 08:05 AM

Talk about convenience. I'm gonna be ordering a AOS today.

wanna986 · 03-30-2009, 06:35 PM

Quote:

Originally Posted by kellysplanet

I noticed that the main sign of this part going bad was pulling the oil cap while running. I tried it after the swap and my car almost died the idle went so low. I could also hear a loud hissing "air suction noise" coming from the part. Did I crack a hose or no lock it in properly? Have any of you heard this? I am afraid to drive it until I can figure if it is done correctly. At least I found the cause of my major oil leak when I swapped this part, I hope that was it, loll. If anybody could give me a sign that it’s okay the noise is normal and the idle drop is normal, it be greatly appreciated.

Not sure I understand...
Are you saying that with the bad part, the cap being pulled off results in the car almost dying?

kellysplanet · 03-30-2009, 08:21 PM

Sorry for the confusion, before pulling the AOS it was very hard to get the oil cap off while the car was running. I guess from the back pressure and had the severe smoke. Now no smoke but when I pulled the oil cap off now the idle goes way down almost to a stall out. I can also hear a loud hiss noise coming from the part, has anyone else tried this yet or heard the noise. I just want to make sure I have the hoses on tight, tripple checked no leaks. I took it for a test drive tonight, ran alot quieter smoother, feels like has more power. While driving slow riding through the movie theater, sounded and felt like was going to stall out. Any guesses.

Thanks,
Kelly

Fletch986 · 03-31-2009, 05:13 PM

Just replaced AOS on 2000 Boxster. It took 3 hours but will be faster the next time. the instructions posted were extremely helpfull. the lower spring loaded clamp was by far the biggest PITA but i ended up cutting the bellows, pulled the AOS out and had better access to the clamp. i replaced the lower clamp with a "screw" type clamp to make the next time easier.

this was my first repair job on the car and i have to say that i hated the "small" work space i had to deal with. my other car is a corvette and i now appreciate having a large engine bay to work in without working around a clamshell.

all in all, not a bad repair and worth the time to DIY instead of paying someone else to do it.

Fletch986

wanna986 · 03-31-2009, 08:03 PM

Quote:

Originally Posted by kellysplanet

Sorry for the confusion, before pulling the AOS it was very hard to get the oil cap off while the car was running. I guess from the back pressure and had the severe smoke. Now no smoke but when I pulled the oil cap off now the idle goes way down almost to a stall out. I can also hear a loud hiss noise coming from the part, has anyone else tried this yet or heard the noise. I just want to make sure I have the hoses on tight, tripple checked no leaks. I took it for a test drive tonight, ran alot quieter smoother, feels like has more power. While driving slow riding through the movie theater, sounded and felt like was going to stall out. Any guesses.

Thanks,
Kelly

Thanks for the clarification. I'm wondering if someone without AOS issues could indeed remove their oil cap and tell us what happens.

I've never had a car that was so sensitive to the removal of the filler cap and, like you, am wondering if this is normal.

Viper5 · 04-04-2009, 10:18 AM

I don't understand how those pictures were taken. Under my car, there is next to no room. The pictures seem to illustrate that this is not the case. I can barely see any of the bolts and clamps.

Viper5 · 04-04-2009, 10:54 AM

I've gotten everything except for the orange part inside of the engine (i'm guessing this just slides out once I take care of my 2nd problem and the lower clamp that is seen in the picture with the pliers. I don't have any room to grab it so I can pull it off.

UPDATE: I managed to successfully instal my new AOS. Took about 3 hours. The hardest part for me was figuring out how to reach the bolts underneath and undoing the lower black grip that you have to squeeze both sides to release. That was a B****. Even getting it back on was somewhat difficult. I also seemed to have disconnected an electrical socket around that part. I think it has to do with the O2 sensors, but I just put it back in after messing around for a little. All in all, great instructions and the pictures really help. Thanks!

kevinniven · 09-01-2009, 02:32 PM

Just called the shop, they want $300 to replace.
Is this truly something the avg person can do at home?
thx guys

mikes_box · 09-01-2009, 05:46 PM

Quote:

Originally Posted by kevinniven

Just called the shop, they want $300 to replace.
Is this truly something the avg person can do at home?
thx guys

$300 for parts and labor is not bad at all. It can be done at home for a few hours of work and cursing for about $100 in parts.. If you do it at home make sure you buy the hose clamp pliers and a new hose clamp that you can jus screw ith your fingers...

Kevfra · 09-08-2009, 12:20 PM

Quote: Most of the failures I do see involve cars with 60-70k miles on them, and it appears to be heat related (air temp 100+ and ground temp 115+) which would equal REALLY high engine compartment temps. This is the ONLY "common" denominator so far. End Quote.

Well mine failed at 60,000 miles on a 102 degree day in slow traffic, so compartment temps were extremely high, plus AC running full tilt. One wonders... why put a heat sensitive part up against an engine?

Two points to mention - I found that using a small vise grips on the bellows clamp during removal was the way to go, as simply using pliers wouldn't do the job.

And second, regarding removing the compartment cover, the ball/socket cable on mine has a small C clip that has to be removed before popping out the ball. Swing the C to the side, then raise it until it comes clear, then pop the ball out.

Fabulous write-up and extremely helpful - many thanks Brad!

Tool Pants · 09-08-2009, 12:40 PM

The temperature related theory is interesting. However Peter Smith thinks it is due to cold air that causes the rubber diagraphram to split.

Unlike the Boxster, the separator on a 996 is heated by coolant. This is a 996 separator and you can see the 2 provisions for the coolant hose into and out of the round thing which is the diagraphram.

Kevfra · 09-10-2009, 11:46 AM

Well I replaced mine - and still have white smoke, although perhaps not as much. I have to drive it to see if it clears, and if the sucking comes back to the oil cap.

Isn't this thing just a minor smog control device, to capture vapor from the crankcase and burn it? In the old days (and on other cars) that would be a very simple matter. This thing seems overly complicated and prone to failure.

Kevfra · 09-10-2009, 01:28 PM

OK - no smoke. Here is what I think...

While I was under there scratching my head, I decided to change the oil. It took about twenty minutes to drain, and I don't mean a slow drip. It was a steady stream of about 1/8 inch diameter for twenty minutes, obviously way longer than it should take if all the oil was in the pan.

I think the AOS failure sucked oil into another area of the engine, and it was sitting there which is why I still had smoke after I replaced the part. But by completely draining the oil I removed it from the inappropriate area - and life is good.

Just put twenty or so miles on it and things appear normal and happy.

Still think it is a stupid design...

Sain0rs · 01-02-2010, 02:05 PM

First off, amazing job with the DIY. I had been concerned about the smoke issue late last year for my '03 S and bought the AOS from pelican parts but hadn't gotten around to installing it. Yesterday the smoking on startup and while running has become extreme so I intend on installing the new AOS.

However, Pelican has two AOS units for sale. The one that I bought (Oil Separator, Boxster/Boxster S (2003-04):
http://www.pelicanparts.com/cgi-bin/smart/more_info.cgi?pn=996-107-026-01-M100&catalog_description=Oil%20Separator%2C%20Boxster%2 FBoxster%20S%20%282003-04%29%2C%20Each

And the one that resembles the AOS in your instructions (Boxster/Boxster S (1997-02) up to Eng # 65X01419):
http://www.pelicanparts.com/cgi-bin/smart/more_info.cgi?pn=996-107-023-04-M100&catalog_description=Oil%20Separator%2C%20Boxster%2 FBoxster%20S%20%281997-02%29%20up%20to%20Eng%20%23%2065X01419%2C%20Each

Anyone have an idea if the install is much more difficult for the 03-04 AOS?

gschotland · 01-02-2010, 02:22 PM

Sounds like you don't really have a choice either way unless the alternative is paying someone else a few hundred bucks to do it. Go for it! And share your results with us on what differed from the write up.

BYprodriver · 01-19-2010, 11:37 AM

Awesome writeup & photos Brad, thanks for posting this. The AOS for my 2000 S did not come with a O-ring just sealant on the tube, do I need the O-ring also to seal the tube going into the block??

BYprodriver · 01-19-2010, 04:06 PM

[QUOTE=BYprodriver]Awesome writeup & photos Brad, thanks for posting this. The AOS for my 2000 S did not come with a O-ring just sealant on the tube, do I need the O-ring also to seal the tube going into the block??[/QUOTE

Pulled the original out of the trash & realized new AOS -04 version has improved seal on the tube & original had single O-ring.