Second thoughts on changing AOS

[Seadweller]

Not to derail, but do these typically fail due to mileage or age?

[jdraupp]

Originally Posted by Seadweller

Not to derail, but do these typically fail due to mileage or age?

Neither. From everything I've read, they can be bad right out of the box or they can last forever. They fail when they fail and there's really no rhyme or reason why.

[Gelbster]

Originally Posted by Seadweller

Not to derail, but do these typically fail due to mileage or age?

The usual item that fails is the diaphragm . It splits and is not accessible for diy replacement.
The cause is probably heat cycles/duration. But overfilling with oil or some other way of 'swamping 'the diaphragm is alleged to harm it.
I read of some in no-frost areas,disconnect and bypass the coolant connections on the AOS.

[Jager]

Atmospheric pressure has a lot to do with the AOS failures. If you live near the coasts these units will fail more often than Boxsters living at higher altitudes. Jake Raby said he has never seen a failed unit from Colorado. I have replaced mine four times and the Jӓgermobile is driven from 20 feet to 120 feet above sea level every day.

[kk2002s]

911monty - I had exact same thoughts 2 summers ago. I was planning a 2000 mile road trip. I bought a new AOS to carry as a spare. I thought the whole drive - how would I change this thing on the side of the road with an engine that has been running for hours.
My Original AOS had 75k+ miles on it at the time
I took 2 more 2000 mile road trips last year with the original and the new as a spare.
This year I bit the bullet and put in the new one. I haven't done much driving yet so the jury is out.
If I do take any Road trips, I'll take my old one as the spare. At least I know how to change it

[jklaspok]

Here's an example off what usually fails with age. Notice the diaphragm split.

[911monty]

Originally Posted by kk2002s

911monty - I had exact same thoughts 2 summers ago. I was planning a 2000 mile road trip. I bought a new AOS to carry as a spare. I thought the whole drive - how would I change this thing on the side of the road with an engine that has been running for hours.
My Original AOS had 75k+ miles on it at the time
I took 2 more 2000 mile road trips last year with the original and the new as a spare.
This year I bit the bullet and put in the new one. I haven't done much driving yet so the jury is out.
If I do take any Road trips, I'll take my old one as the spare. At least I know how to change it

HAHA! I can relate to those thoughts. I get them even close to home at my mileage. I don't know if you've ever driven through the Mojave desert, but it's a bit like the surface of the moon in appearance and the temperature of Hades. I'm pretty sure the lizards would jump on the hot muffler to cool their feet off! No place to be broke down for sure, so I don't want to even be thinking of the AOS out there.

[Gilles]

Originally Posted by 911monty

I don't know if you've ever driven through the Mojave desert, but it's a bit like the surface of the moon in appearance and the temperature of Hades.

+ 1 about the Mojave Desert

911monty,
I had been at Willow Springs with the POC in early September, and your biggest concern is to keep yourself hydrated, something like survival mode, (literally)... LOL

After the first weekend there, I went ahead and installed the third (center) radiator

[911monty]

Originally Posted by Gilles

+ 1 about the Mojave Desert

911monty,
I had been at Willow Springs with the POC in early September, and your biggest concern is to keep yourself hydrated, something like survival mode, (literally)... LOL

After the first weekend there, I went ahead and installed the third (center) radiator

Gilles; Yeah it really is no joke out there.

Funny (or not) you mention the radiator. I have had both radiators off and cleaned. Fans working well. New WP and LN low temp stat and still my temps swing from just a tick below the 180 mark to the right edge of the 0, 103 deg C or 217 f. indicated on the climate control at 70 to 80 deg f ambient when working the engine in the hills and twisties rowing 2nd to 3rd. I am considering upgrading stock rads to the CSF rads. This way I replace the 18 YO rads without all the mods for the center rad which should end up about cost neutral. This trip is kinda the litmus test.

[Ja986s]

Originally Posted by Gelbster

But overfilling with oil or some other way of 'swamping 'the diaphragm is alleged to harm it.

I overfilled my 2000S. It was fine until I tracked the car. AOS failed. Common failure when driving on a track with too much oil.