A6 4.2 owners, I went ahead and ordered up some aluminum Oil Cooler Pipes.
02-18-2009, 07:36 AM
#1
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A6 4.2 owners, I went ahead and ordered up some aluminum Oil Cooler Pipes.
<center><img src="http://pictureposter.audiworld.com/38899/a8pipe.jpg"></center><p>
Based on what I could find, the Buna Rubber O-ring that Audi uses is only good for 250F which means that is close to failing and will fail if the car overheats slightly. With the thermostat problems on 4.2s I think this is likely one of the design problems with this part. The plastic also seems to degrade with time..
So I went with two standard 1/16" Viton O rings on each side. The pipe is 6061 Aluminum.
O.D. with the Orings fitted is .775-.78" which means it will fit as per the original plastic pipe.
$25 dollars, shipping included with 4 Viton O-rings.
Based on what I could find, the Buna Rubber O-ring that Audi uses is only good for 250F which means that is close to failing and will fail if the car overheats slightly. With the thermostat problems on 4.2s I think this is likely one of the design problems with this part. The plastic also seems to degrade with time..
So I went with two standard 1/16" Viton O rings on each side. The pipe is 6061 Aluminum.
O.D. with the Orings fitted is .775-.78" which means it will fit as per the original plastic pipe.
$25 dollars, shipping included with 4 Viton O-rings.
02-18-2009, 07:46 AM
#3
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This goes between the Oil cooler and the block on 4.2 engines
<center><img src="http://farm4.static.flickr.com/3524/3279861694_035b60f07a.jpg?v=0"></center><p>
The Audi part is a plastic pipe with a Buna O-rings. It breaks and causes leaks.
I designed up this part using two Viton O-rings per side with a lathed up aluminum pipe.
Double the sealing power, double the temperature tolerance and appox. 10 times the strength in the pipe.
I'd say this is a lifetime part.
<img src="http://farm4.static.flickr.com/3321/3273366096_5489a58c35.jpg?v=0">
The Audi part is a plastic pipe with a Buna O-rings. It breaks and causes leaks.
I designed up this part using two Viton O-rings per side with a lathed up aluminum pipe.
Double the sealing power, double the temperature tolerance and appox. 10 times the strength in the pipe.
I'd say this is a lifetime part.
<img src="http://farm4.static.flickr.com/3321/3273366096_5489a58c35.jpg?v=0">
02-18-2009, 07:49 AM
#4
AudiWorld Super User
temperature coefficient of expansion diffo between plastic and Al?
Probably won't make any difference once installed.....
02-18-2009, 08:04 AM
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Aluminum is less, its more stable.
The O-rings must do the sealing otherwise the Factory part would leak all the time when the car is cold.
Thought about that. thats why I used a double viton seal. The grooves I cut are also rounded at the bottom whereas the factory plastic pipe has square cut out for the O-ring which reduces sealing pressure as the O-ring squares off. The square groove in the plastic pipe also creates a stress concentration where it often fails. The necked down portion is removed.
Thought about that. thats why I used a double viton seal. The grooves I cut are also rounded at the bottom whereas the factory plastic pipe has square cut out for the O-ring which reduces sealing pressure as the O-ring squares off. The square groove in the plastic pipe also creates a stress concentration where it often fails. The necked down portion is removed.
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02-18-2009, 08:09 AM
#9
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Outstanding. Thank you.
