New Porsche AOS reading 5.3 WC - opinions??
 

After replacing my ver.00 AOS with a new Porsche Genuine AOS ver.01 I was disappointed to find that the new AOS was still reading between 6.21 and 7.28 inWC. Pretty much what the old one was reading. Here’s my original thread:

http://986forum.com/forums/performance-technical-chat/69866-if-ain%92t-broke-don%92t-fix.html

Not trusting my $35 manometer, I ordered a Fieldpiece manometer. With the Fieldpiece my new AOS is reading in the high fives cold and 5.32 - 5.41 warm. The cheap manometer is off by ~1 inWC

https://uploads.tapatalk-cdn.com/201...d9f2701fef.jpg

JFP indicated that anything above 5.0 warm is candidate for replacement. The Pelican article says 4-7 is ok. I think I’m going to call it good at 5.32, watching for symptoms and monitoring WC regularly. I really don’t want to go back in and risk breaking the AOS plastic squeeze clamps unless I really need to.

What do you guys think???


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4-7 is OK on a cold start, but 5 is our limit warmed up. Yours is marginal, so I would leave it alone, but check it regularly to see if starts going up.

Nice manometer by-the-by.....

Hi JFP, thanks for the quick response. Good news! I’ll leave it and monitor. At least I’m within spec for the cold start and now I have the latest version.

The Fieldpiece is awesome, thanks. I know better than to try and cheap out on important equipment but I slip sometimes.

Quick update. I finally checked the vacuum with the car fully warmed up. As JFP advised, it’s just like the cam variance - only check it when the car is truly at operating temp after a good run. My new AOS is well in spec:

https://uploads.tapatalk-cdn.com/201...511d3a9091.jpg

Done!


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I have owned 996’s and a 997, but I am not familiar with this AOS test.

I am having a PPI done next week on a 986. Is this test routinely done as part of a PPI? If not, do I just request an AOS manometer test?

Thanks.

It should be, but it never hurts to ask. We check the AOS on every car passing through the shop, regardless what it is in for. Only takes a min.

Many thanks!

What’s the best way to connect the manometer to gain the reading?

An old oil fill cap with a fitting mounted to it.

Besides the AOS, what can the Fieldpiece manometer help you diagnose on a vehicle?

A digital manometer can read both pressure and vacuum very accurately, so anywhere you would be testing either. Its major advantage is in the fact that it can read very low levels of either.

Thanks! That's what I figured!

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