AOS replacment

[blackboxster]

I plan on ordering a new AOS and replacing it and would like to know if I just need AOS and vent line hose or anything else like new O-rings? I asked sunset if they had the recommended lubrication "klube" but they said the techs just recommend spraying the o-rings with silicone lubricant. The reason I am doing this replacement before anyone asks, I have had some cold idling problems after start up I replaced the MAF and cleaned the throttle body. I read the forums and it sounds like the AOS needs replaced whenever you remove the oil cap and suction comes from oil filler tube, mine did bad and car almost died like a gasping for air sound. I have also been having really bad emission smell after startup that stinks up the garage for hours like carbon dioxide/gas smell, hope this hasn't effected the O2 sensors yet. Any recommedations? My Boxster is a 2000 2.7.

[ericinboca]

I plan on ordering a new AOS and replacing it and would like to know if I just need AOS and vent line hose or anything else like new O-rings? I asked sunset if they had the recommended lubrication "klube" but they said the techs just recommend spraying the o-rings with silicone lubricant. The reason I am doing this replacement before anyone asks, I have had some cold idling problems after start up I replaced the MAF and cleaned the throttle body. I read the forums and it sounds like the AOS needs replaced whenever you remove the oil cap and suction comes from oil filler tube, mine did bad and car almost died like a gasping for air sound. I have also been having really bad emission smell after startup that stinks up the garage for hours like carbon dioxide/gas smell, hope this hasn't effected the O2 sensors yet. Any recommedations? My Boxster is a 2000 2.7.

The Kluber Sytheso Glep is silicon grease and is applied to the O ring on the base of the AOS - and the O ring should come on the part. Spraying with a silicon lubricant should work or using any readily available silicon grease.

I replaced my AOS with a Porsche Motorsports AOS (track car) and I reused all the stock lines. I still have one of the lines I ordered in my parts bin, collecting dust.

Be sure you get the bottom rubber hose that has a spring clamp on it back on all the way. The other lines have fittings that engage nicely, and you can tell easily with an audible click if they are properly attached.

[wvicary]

Be careful with the silicone spray, too much and it gets drawn into the engine and burnt in combustion which can contaminate the O2 sensors. It's safer to just lube the O-ring with motor oil.

[blackboxster]

I never thought about using some motor oil on it sounds like a good idea. Do you think replacing the AOS might help eliminate the strong emmision smell after startup? It doesn't smoke very much unless it has not been started for a while.

[wvicary]

AOS have a high failure rate so it could be the problem. How many miles on the spark plugs? The ignition coils have been known to crack and cause misfires at cold starts... it often smells like fuel when that happens, does the engine run rough at cold starts? Have you had any check engine lights or codes?

[blackboxster]

No check engine light on yet. I have 45,000 miles at the most on the spark plugs I bought it when it had 39,000 miles on it.

I ordered new plugs with AOS to be installed, but the idle just drops on 1st start of the day. Even if the car has sat 8 hours after first start it only does on completely cold engine. It drops to about 300 rpms after about 5 seconds after starting sounds like its going to die then usually jumps back up by itself, sometimes I give it a little gas and it will then idle smoothly.

[usaf-lt-g]

No check engine light on yet. I have 45,000 miles at the most on the spark plugs I bought it when it had 39,000 miles on it.

I ordered new plugs with AOS to be installed, but the idle just drops on 1st start of the day. Even if the car has sat 8 hours after first start it only does on completely cold engine. It drops to about 300 rpms after about 5 seconds after starting sounds like its going to die then usually jumps back up by itself, sometimes I give it a little gas and it will then idle smoothly.

Hmm anyone know if Sunset can get that Motorsports AOS and any other additional parts necessary? I'm almost tempted to install that one instead.

[ericinboca]

No check engine light on yet. I have 45,000 miles at the most on the spark plugs I bought it when it had 39,000 miles on it.

I ordered new plugs with AOS to be installed, but the idle just drops on 1st start of the day. Even if the car has sat 8 hours after first start it only does on completely cold engine. It drops to about 300 rpms after about 5 seconds after starting sounds like its going to die then usually jumps back up by itself, sometimes I give it a little gas and it will then idle smoothly.

Hmm anyone know if Sunset can get that Motorsports AOS and any other additional parts necessary? I'm almost tempted to install that one instead.

There is a DIY for a Porsche Motorsports AOS install in a 986 over in the Boxster Mods section. The motorsports AOS is about twice the size of the stock - has much greater capacity. I installed in my 986 because the Gs on certain turns n certain circumstances overwhelmed the stock AOS. There were very specific symptoms for the need. It is not that the stock AOS had anything wrong with it. It is an expensive part compared to the stock part. You'd have to judge if you need it.