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So I normally check my AOS when I change my oil.
I last checked it May 28th and it was a solid 5 inH2O.
I realized I didn't check it when I dropped the sump and installed the LN Engineering 2qt deep sump on November 1st.
I've driven maybe 6K miles since the last test.
I decided to check it real quickly last night when I arrived from my commute home.
I hooked my manometer up and it was just slightly above 5.
I waited for it to stabilize to write down the value and it slowly crept up...and up...and up...until...
I'd hoped it would get bad gradually.
I have not seen smoke or any other issues.
I’ve never checked my AOS or even pulled the cap. So does this mean you have a replacement coming shortly? If you have no smoke, then what’s going to happen next?
TexSquirrel, I use a manometer on almost a daily basis for negative air testing as part of my business, the one thing I have found over the last 25+ years is that if the battery is even slightly low it will affect the readings. I would try changing the battery just to make sure, I too perform a crankcase pressure test at every oil change for the same reasons as you and get slightly higher readings at cold start (approx 5.15 in.) but get a consistent reading of approx 4.5" at operating temperature.
I’ve never checked my AOS or even pulled the cap. So does this mean you have a replacement coming shortly? If you have no smoke, then what’s going to happen next?
I'm going to re-test with a fresh battery on a slightly warmer day.
This Friday is my last day at work, so I'll have more time to spend with my 996(oh, and my family too) soon.
If I get the same readings, which I expect but I'm hoping for closer to normal, I'll order a factory AOS and start talking myself into changing it when it arrives.
Originally Posted by wyovino
Is that a professional (i.e, expensive) manometer or is it cheapskate-friendly?
Cheap one, with a home made oil filler cap adapter.
Originally Posted by SoCal911t
Bill, I have the cheapskate-friendly version. While I have yet to use it to test the AOS, I have tested it against a fancy one and it's accurate.
That's good to hear!
Originally Posted by texcwa
TexSquirrel, I use a manometer on almost a daily basis for negative air testing as part of my business, the one thing I have found over the last 25+ years is that if the battery is even slightly low it will affect the readings. I would try changing the battery just to make sure, I too perform a crankcase pressure test at every oil change for the same reasons as you and get slightly higher readings at cold start (approx 5.15 in.) but get a consistent reading of approx 4.5" at operating temperature.
I'll change the battery, which is probably at least a year old now, and retest.
My current AOS was installed by FSI back in 2013 (about 30K miles ago) when they installed The IMS Solution.
I probably need to replace the water pump soon too since it was last changed then too.
My current AOS was installed by FSI back in 2013 (about 30K miles ago) when they installed The IMS Solution.
I probably need to replace the water pump soon too since it was last changed then too.
Hey man, my AOS was recently pre-qual tested for the IMS solution and my AOS was showing low numbers. I'm sure you know that Raby recommends that if the AOS is producing numbers high numbers on the manometer, then it definitely needs replacement. Do you have access to a CR Tools Manometer?
Hey man, my AOS was recently pre-qual tested for the IMS solution and my AOS was showing low numbers. I'm sure you know that Raby recommends that if the AOS is producing numbers high numbers on the manometer, then it definitely needs replacement. Do you have access to a CR Tools Manometer?
Yeah, I checked the Pre-qual video again just to make sure of what he said.
I'm going to replace it if I get another high reading this weekend.
I'm also going with a factory one unless someone has a better option.
Jake also said that low numbers could indicate bore scoring.
But if yours was properly pre-qualified I wouldn't worry about low numbers.
Unfortunately I don't have access to a CR tools manometer.
Yeah, I checked the Pre-qual video again just to make sure of what he said.
I'm going to replace it if I get another high reading this weekend.
I'm also going with a factory one unless someone has a better option.
Jake also said that low numbers could indicate bore scoring.
But if yours was properly pre-qualified I wouldn't worry about low numbers.
Unfortunately I don't have access to a CR tools manometer.
Yea, bore scoring was a big concern of mine. They bore scoped the cylinders and replaced the AOS. I'm assuming they checked the manometer reading after the car was finished up. Personally, I wouldn't recommend getting an aftermarket AOS. Stick with the OEM factory part. Too much trouble to change it out if the aftermarket AOS sucks a big one. (no pun intended) hahaha
Yea, bore scoring was a big concern of mine. They bore scoped the cylinders and replaced the AOS. I'm assuming they checked the manometer reading after the car was finished up. Personally, I wouldn't recommend getting an aftermarket AOS. Stick with the OEM factory part. Too much trouble to change it out if the aftermarket AOS sucks a big one. (no pun intended) hahaha
Personally, I wouldn't recommend getting an aftermarket AOS. Stick with the OEM factory part. Too much trouble to change it out if the aftermarket AOS sucks a big one. (no pun intended) hahaha
Yea, bore scoring was a big concern of mine. They bore scoped the cylinders and replaced the AOS. I'm assuming they checked the manometer reading after the car was finished up. Personally, I wouldn't recommend getting an aftermarket AOS. Stick with the OEM factory part. Too much trouble to change it out if the aftermarket AOS sucks a big one. (no pun intended) hahaha
Even the Porsche branded AOS's have been known to be bad right out of the box...I remember reading a thread a year or two ago where JR said he had gotten a high rate of failures (like 2 out of 3 or something along those lines) and he only uses the factory AOS
12-11-2018, 01:11 PM
Well that AOS went from OK to bad quickly
That would really suck!
