AOS boot/ bellow failure?

[professorman]

I see some oil dampness on the right side of my engine. I think the lower boot bellow for my AOS is leaking.

Is that something that can be changed easily? Or does it require the entire AOS to be removed?

I don’t think I have a bad AOS. It was changed at the dealer 2 years, 15k miles ago. I have no symptoms of AOS failure.

2001 Boxster S

[78F350]

First, I'd remove the wheel and check if the leak looks more like it's coming from a spark plug tube.
My opinion - The bellows is the difficult part of swapping the AOS. The rest of it is easier to reach. If it's possible to install the bellows with the AOS still installed, it would be a lot more work than removing it and installing it correctly.

I did this video a few years ago and it may help you visualize the situation.

[JFP in PA]

Originally Posted by professorman

I see some oil dampness on the right side of my engine. I think the lower boot bellow for my AOS is leaking.

Is that something that can be changed easily? Or does it require the entire AOS to be removed?

I don’t think I have a bad AOS. It was changed at the dealer 2 years, 15k miles ago. I have no symptoms of AOS failure.

2001 Boxster S

Yes, these boots can and do leak. If yours is leaking, yes you have to remove the AoS to get a it, and I would HIGHLY recommend replacing the AoS along with the boot, and ONLY USE THE FACTORY AoS, NEVER AN AFTERMARKET UNIT.

[professorman]

Originally Posted by 78F350

First, I'd remove the wheel and check if the leak looks more like it's coming from a spark plug tube.
My opinion - The bellows is the difficult part of swapping the AOS. The rest of it is easier to reach. If it's possible to install the bellows with the AOS still installed, it would be a lot more work than removing it and installing it correctly.

I did this video a few years ago and it may help you visualize the situation.

Thanks for the video. That gives a lot of context.
My full AOS was replaced by the dealer 2 years 15/miles ago. All the rubber should still be good and not hardened. I am thinking of maybe re-seating the clamps. Maybe something is up with the sealing surface.
I would hate to think that OEM parts installed by the dealer failed so quickly.

[JFP in PA]

Originally Posted by professorman

I would hate to think that OEM parts installed by the dealer failed so quickly.

It would not be the first time................

[bcrdukes]

Originally Posted by JFP in PA

Yes, these boots can and do leak. If yours is leaking, yes you have to remove the AoS to get a it, and I would HIGHLY recommend replacing the AoS along with the boot, and ONLY USE THE FACTORY AoS, NEVER AN AFTERMARKET UNIT.

Bump.

Agreed 100%. I had mine replaced by a URO and the bellow cracked. So much for a replacement

Mine is in the shop this week to have it replaced.

Edit: For context, I had my AOS replaced in 2019. Since 2022, it's mostly seen DE days with my local PCA so it gets driven hard.

[professorman]

I think the dealer didn’t install my clamp properly. I got 2 new clamps on the same boot and it’s holding properly now. It was really a pain to do. But got it done.

[husker boxster]

Miles and age are not necessarily the only factors when it comes to replacing an AOS. How you drive can also determine health. Long runs in the upper RPM range can tear the membrane inside the AOS. Some tracks I run will go thru an AOS regardless of how new or old it is. The roval at Kansas Speedway is a perfect example. Driving NASCAR T3 was 5K+ rpm in 4th gear and T4 thru the main straight was 5th gear at 5K+ rpm. There wasn't appropriate time or locn to upshift so the AOS sustained very high rpm for the majority of the lap. It was toast after 2 days.

[professorman]

That’s crazy to have such a fickle part on the car.

[JFP in PA]

Originally Posted by professorman

That’s crazy to have such a fickle part on the car.

The part isn't as "fickle" as you might imagine; by far, its biggest problem is over filling the oil system in these engines. Several years ago, Porsche NA issued a tech bulletin recommending lowering the oil levels two to three bars below the full mark on the dash display, and even released recalibrated dip sticks for cars still equipped with one.

Those of us out in the field that see these cars everyday had begun lowering the oil levels slightly because we found it addressed two common problems:

1. The occasional "smokey startup" was dramatically reduced and even eliminated.
2. The life span of the AOS increased significantly.

[bcrdukes]

Originally Posted by JFP in PA

The part isn't as "fickle" as you might imagine; by far, its biggest problem is over filling the oil system in these engines. Several years ago, Porsche NA issued a tech bulletin recommending lowering the oil levels two to three bars below the full mark on the dash display, and even released recalibrated dip sticks for cars still equipped with one.

Those of us out in the field that see these cars everyday had begun lowering the oil levels slightly because we found it addressed two common problems:

1. The occasional "smokey startup" was dramatically reduced and even eliminated.
2. The life span of the AOS increased significantly.

JFP - Thanks for this.

Is there a part number for the recalibrated dip sticks? Or is this not applicable to the 986?

Update: Turns out only the boot / bellow was torn and there were signs of oil on the side. The AOS itself tested okay.

[JFP in PA]

Originally Posted by bcrdukes

JFP - Thanks for this.

Is there a part number for the recalibrated dip sticks? Or is this not applicable to the 986?

Update: Turns out only the boot / bellow was torn and there were signs of oil on the side. The AOS itself tested okay.

A dealer should be able to give you the part number for the updated 986 dip sticks.

[bcrdukes]

Thank you!