Yesterday, I replaced the
AOS
on my
987.2
and thought I’d write up a guide on it. It was generally a fairly easy job, the most difficult part being working the
AOS
out of the engine bay. I think it took me 1 to 1.5 hours to complete.
Note:
These instructions are specific to the 987.2.
Replacing the AOS in a 987.1 is an entirely different process. If you’re changing the AOS on your 987.1 here are some great guides:
PelicanParts 986/987.1 AOS Replacement
DIY 987.1 AOS Replacement
Links
DIY 987.2 AOS Replacement
987.2 S AOS Replacement
(same process)
Tools/Supplies Needed:
T30 Torx socket
E10 Torx socket (preferably magnetic and not a deep socket)
10 in wrench extension
10mm hex socket
Plastic trim removal tool
New Air Oil Separator (part #: 0PB-115-099-A)
Optional: Compressed air for cleaning some dust in the engine bay
Steps:
Using a trim removal tool, remove the carpeting above the upper engine access panel. Remove the engine access panel.
[T30 Torx socket]
Remove the carpeting and front engine access panel behind the seats.
[10mm hex socket]
You can now see the AOS in the top left (from behind the car). It sits in front of the intake manifold next to the air intake box. Before removing anything, use compressed air to clean up dust near the AOS.
Identify the top breather line that leads to the intake manifold. Remove it by squeezing the connector at the ridged pinch points and gently pulling it off.
From inside the car looking into the front engine access panel, remove the visible bolt
[E10 Torx socket]
holding the AOS in. Make sure not to drop the bolt. Use a magnetic socket or magnet to secure the bolt as it comes out.
In between the AOS and the intake manifold, there is a bolt securing a bracket for a couple wires/hoses. Remove this bolt
[E10 Torx socket]
and move the bracket and wires out of the way.
Now remove the other bolt
[E10 Torx socket w/ 10in extension]
securing the AOS (in between the AOS and the intake manifold). This is easiest to see from behind the driver's seat, looking down behind the AOS. Again, make sure not to drop the bolt. Use a magnetic socket or tool to carefully remove the bolt.
Now the AOS is only secured by the two holes/O-rings on the bottom. Gently rock the AOS back and forth while pulling upward to work it off the engine.
With the AOS free from the engine, gently work it out of the engine bay. Take note of the angle and rotations used to remove it so you can replicate this to install the new one. To see how to work it out, watch
here
starting at 10:20:
With the AOS separated from the engine and looking at it from the upper engine compartment, rotate the circular top to the right to turn the AOS upside down.
Once it’s upside down, turn the circular top facing the rear of the car.
With the O-rings facing towards you, rotate the AOS counterclockwise until the circular top is facing upward and pull it out.
Put some motor oil on the O-rings of the new AOS to lubricate it. Now gently work the new AOS back into the engine bay and rotate it to the correct position. Once it’s in the correct position, push the AOS down into the engine. Note that the bolts will need to be re-installed to fully push it down.
Re-install the two bolts that secure the AOS in position.
[E10 Torx socket]
Start with the rear bolt that is accessed from the upper engine access panel. Start each bolt by hand to make sure they’re not cross threaded.
Reconnect the top breather line to the AOS.
Re-install the wires and bracket to their proper position.
[E10 Torx socket]
Re-install the front engine access panel
[10mm hex socket]
and carpet.
Start the car and run it for a couple minutes. Go for a short test drive.
Re-install the upper engine access panel and carpet.
[T30 Torx socket]
.
I was going to tackle this job and do the serpentine belt at the same time, then for giggles, I asked my local independent specialist what he would charge. $460,
including parts
.
I'm normally a DIY guy for sure, but at that price? I let him have at it!
And thanks MUCH to
@three
for a great writeup. Normally writeups are done with photos -
@three
has created one that doesn't need photos, his descriptive skill is exceptional. I could envision exactly what he describes doing. WELL DONE!
And miss out on the fun of getting into the engine? It's a fun - and fairly low-risk - DIY project.
It is possible my definition of fun is a little strange, I'll grant you.
I'm a geek and enjoy the details. Gives me something to do when I can't drive the car lol.
Hope it helps someone down the line. I know the guides on here and other forums have helped me countless times.
Yeah, I replaced the tensioner, pivot bolt, and roller a few years back. I'd heard a few reports of the pivot bolt breaking, and the plastic tensioner roller definitely had some wear on it.
Thank you for contributing to the
987.2
brotherhood!
Thanks for sharing, nice work
