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AOS - Coolant vs Non-Coolant


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My 2004 Targa has started leaking coolant. I've found the source, and it's the AOS. I called my local Porsche shop to get a replacement, and they only one they can get is the AOS that doesn't have any connections for coolant lines. Will this work in my car? If so, what do I do with those existing coolant lines that went to the old one?

Thanks!

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The ones without the coolant lines are for Boxsters/Caymans so if you want to keep everything stock, I don't recommend using it. The one for our car should be easy to find. Have you checked with local dealers?

The coolant lines are there to prevent AOS freezing in cold weather. If you really want to, you can just connect the two lines with a pipe nipple to bypass the AOS. 5mm ID amd 8mm OD.

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  • 1 month later...

Sorry in advance but I have not found this discussed yet in the threads I have searched...

 

If you live in a warm climate and always drive your car in conditions above freezing, is there a net benefit to just using the 986 version without cooling exchange and then simply connect the cooling hoses together to bypass the AOS... seems that would avoid the risk of fluid exchanges upon failure if I am following these threads correctly.  The potential potential fluid exchange upon failure seems like a huge costly or damaging mess if it went south in that fashion (not all do I understand)... versus giving up on AOS performance in cold/freezing conditions (the downside to excluding the coolant flow to the AOS as I fathom it)?  What am I missing?  Is coolant through the AOS more beneficial than I comprehend? Thoughts?

 

I just tested my car on a warm engine and it was drawing 10-11 inches of water on a calibrated gauge my buddy just happened to have on him. I have no white smoke or any oil in my Throttle Body or intake or any other symptoms but this higher than normal (?) vacuum at the filler neck... so am I right to change it now preventatively before leaking, or worse case fluid exchanges (oil into coolant passages, coolant into oil passages).

 

Thanks for anyone's insight into my dilema... replace or wait, and when replace use 911 version or 986 version?

 

-John

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Sorry in advance but I have not found this discussed yet in the threads I have searched...

 

If you live in a warm climate and always drive your car in conditions above freezing, is there a net benefit to just using the 986 version without cooling exchange and then simply connect the cooling hoses together to bypass the AOS... seems that would avoid the risk of fluid exchanges upon failure if I am following these threads correctly.  The potential potential fluid exchange upon failure seems like a huge costly or damaging mess if it went south in that fashion (not all do I understand)... versus giving up on AOS performance in cold/freezing conditions (the downside to excluding the coolant flow to the AOS as I fathom it)?  What am I missing?  Is coolant through the AOS more beneficial than I comprehend? Thoughts?

 

I just tested my car on a warm engine and it was drawing 10-11 inches of water on a calibrated gauge my buddy just happened to have on him. I have no white smoke or any oil in my Throttle Body or intake or any other symptoms but this higher than normal (?) vacuum at the filler neck... so am I right to change it now preventatively before leaking, or worse case fluid exchanges (oil into coolant passages, coolant into oil passages).

 

Thanks for anyone's insight into my dilema... replace or wait, and when replace use 911 version or 986 version?

 

-John

 

OK, let's take this one bit at a time.  Coolant lines on a 996:  Very few AOS failures result in an intermix problem; usually when the AOS fails you get clouds of smoke from oil being sucked into the intake due to excessive vacuum in the system.  I replace these things for a living, and every 996 leaving the shop has the coolant version.  The 986 has never shown any freeze up tendencies, so no coolant is necessary.

 

Because the AOS connection to intake vacuum is actually behind the throttle body, you will never see any oil in the TB.

 

If you are pulling 10-11 inches of water at the oil fill cap (a good AOS will pull 4-7 inches of water on a cold start, but level off at 5 inches or less vacuum warm), your AOS is toast and should be changed out before you start sucking liquid oil into the intake, which can hydro lock the engine and kill it.  Buy a new factory (not aftermarket) AOS and change it before something really stupid happens.

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Sorry in advance but I have not found this discussed yet in the threads I have searched...

 

If you live in a warm climate and always drive your car in conditions above freezing, is there a net benefit to just using the 986 version without cooling exchange and then simply connect the cooling hoses together to bypass the AOS... seems that would avoid the risk of fluid exchanges upon failure if I am following these threads correctly.  The potential potential fluid exchange upon failure seems like a huge costly or damaging mess if it went south in that fashion (not all do I understand)... versus giving up on AOS performance in cold/freezing conditions (the downside to excluding the coolant flow to the AOS as I fathom it)?  What am I missing?  Is coolant through the AOS more beneficial than I comprehend? Thoughts?

 

I just tested my car on a warm engine and it was drawing 10-11 inches of water on a calibrated gauge my buddy just happened to have on him. I have no white smoke or any oil in my Throttle Body or intake or any other symptoms but this higher than normal (?) vacuum at the filler neck... so am I right to change it now preventatively before leaking, or worse case fluid exchanges (oil into coolant passages, coolant into oil passages).

 

Thanks for anyone's insight into my dilema... replace or wait, and when replace use 911 version or 986 version?

 

-John

 

OK, let's take this one bit at a time.  Coolant lines on a 996:  Very few AOS failures result in an intermix problem; usually when the AOS fails you get clouds of smoke from oil being sucked into the intake due to excessive vacuum in the system.  I replace these things for a living, and every 996 leaving the shop has the coolant version.  The 986 has never shown any freeze up tendencies, so no coolant is necessary.

 

Because the AOS connection to intake vacuum is actually behind the throttle body, you will never see any oil in the TB.

 

If you are pulling 10-11 inches of water at the oil fill cap (a good AOS will pull 4-7 inches of water on a cold start, but level off at 5 inches or less vacuum warm), your AOS is toast and should be changed out before you start sucking liquid oil into the intake, which can hydro lock the engine and kill it.  Buy a new factory (not aftermarket) AOS and change it before something really stupid happens.

 

That's pretty straight to the point, I appreciate the advice and will get the part on order.  I wonder what that plastic tube coming into my intake track just before the TB is if not AOS connection... I have the X-51 kit in case that makes a difference in your response.  thx

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Sorry in advance but I have not found this discussed yet in the threads I have searched...

 

If you live in a warm climate and always drive your car in conditions above freezing, is there a net benefit to just using the 986 version without cooling exchange and then simply connect the cooling hoses together to bypass the AOS... seems that would avoid the risk of fluid exchanges upon failure if I am following these threads correctly.  The potential potential fluid exchange upon failure seems like a huge costly or damaging mess if it went south in that fashion (not all do I understand)... versus giving up on AOS performance in cold/freezing conditions (the downside to excluding the coolant flow to the AOS as I fathom it)?  What am I missing?  Is coolant through the AOS more beneficial than I comprehend? Thoughts?

 

I just tested my car on a warm engine and it was drawing 10-11 inches of water on a calibrated gauge my buddy just happened to have on him. I have no white smoke or any oil in my Throttle Body or intake or any other symptoms but this higher than normal (?) vacuum at the filler neck... so am I right to change it now preventatively before leaking, or worse case fluid exchanges (oil into coolant passages, coolant into oil passages).

 

Thanks for anyone's insight into my dilema... replace or wait, and when replace use 911 version or 986 version?

 

-John

 

OK, let's take this one bit at a time.  Coolant lines on a 996:  Very few AOS failures result in an intermix problem; usually when the AOS fails you get clouds of smoke from oil being sucked into the intake due to excessive vacuum in the system.  I replace these things for a living, and every 996 leaving the shop has the coolant version.  The 986 has never shown any freeze up tendencies, so no coolant is necessary.

 

Because the AOS connection to intake vacuum is actually behind the throttle body, you will never see any oil in the TB.

 

If you are pulling 10-11 inches of water at the oil fill cap (a good AOS will pull 4-7 inches of water on a cold start, but level off at 5 inches or less vacuum warm), your AOS is toast and should be changed out before you start sucking liquid oil into the intake, which can hydro lock the engine and kill it.  Buy a new factory (not aftermarket) AOS and change it before something really stupid happens.

 

That's pretty straight to the point, I appreciate the advice and will get the part on order.  I wonder what that plastic tube coming into my intake track just before the TB is if not AOS connection... I have the X-51 kit in case that makes a difference in your response.  thx

 

 

The AOS vacuum connection has to be after the throttle body, or there would be no vacuum.  The intake ahead of the throttle body is at atmospheric pressure.

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