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My 2004 Carrera coupe has developed a leak.  It started after I flushed my cooling system.  Rather sure it is around the AOS/associated lines.  I've read various opinions about the difficulty of removing the AOS.  But what I am interested in doing is just replacing those lines.  Any experience or opinions on doing this?  Specifically, is it even possible?  Especially if this can be done without removing the intake manifold?

 

Also I am only finding the upper oil separator coolant hose.  What about the second one?

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If you are in a mild climate ,the coolant hoses to the AOS are redundant. Some just disconnect and plug them. Search for details and comments.

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Having done an AOS replacement on my car, you cannot access the AOS coolant lines without removing the Bank 1 intake.  No way to get to those hoses and clamps, even with the motor dropped down to the lowest point.  You might as well just replace the AOS while you're at it.

The coolant lines #12 and #13 - #12 comes from the water pump and #13 crosses over and goes down underneath the engine.

See diagram here http://www.autoatlanta.com/porsche-parts/hardparts.php?dir=996-99-05&section=104-10

For a temporary fix, or total bypass of the coolant to the AOS, one just needs to plug the two hoses or find a way to connect them together.

Edited by DBJoe996

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Posted (edited)

 Guys,

 

I just removed my AOS (detailed removal write up to follow later) and noticed that the 2 coolant lines located on the sunflower face area of the AOS have no hoses attached to them!  Obviously the AOS was previously replaced but the original hoses were never connected.  And these 2 nipples were not blocked off/bypassed or connected together as mentioned above. 

 

So my question is where do these 2 AOS coolant hoses go/connect to? 

 

When I was pulling the car apart, the thin coolant hose that goes from the engine block cap (right below the alternator and connected to the joining socket part Number 99610622652) was connected directly to the 3 way splitter hose (which connects to the water pump and the expansion tank).  I'm thinking this is hose 13?

 

I'm thinking this coolant hose should originally be going to the AOS (right side nipple of the face) and then the left side nipple of the AOS coolant hose (hose 12?) should be going to the connection on the 3 way splitter hose?   I'm really confused now.

 

Car is a 1999 manual cab C4.

Edited by rhkwon

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That doesn't make much sense.  The coolant lines going to the AOS are under constant pressure from the coolant system from the connection on the water pump, so they have to either be internally blocked or connected together to make a loop bypass.  The coolant lines to the AOS help heat up the AOS during low temp running/first start up to assist with air/oil separation.

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