How to burp an allroad
AudiWorld Senior Member
Joined: Dec 2010
Posts: 826
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Do what I did in post #14. My symptoms were the same as yours. Very cheap and most likely will fix it. Common AR problem with air bubble and sediment getting trapped in the heater core. When you get to the burping process, super fill the reservoir and elevate it as high as you can. Have a helper rev the engine a few times.
AudiWorld Member
Joined: Aug 2011
Posts: 139
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From: Orange, CT
What is this CRL stuff, where can I get it, and how did you flush just the heater core? Did you dis-connect the lines, and attach remote inlet/outlet lines and flush it that way? I can imagine that's how to flush JUST THE CORE, but I'm wondering how you let JUST THE CORE soak in CRT for 20 min.
AudiWorld Member
Joined: Aug 2011
Posts: 139
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From: Orange, CT
Update: heater core is hot at both ends
I drove the car around town today, temp guage straight up, then checked by TOUCH the inlet and outlet pipes of the heater core. Inlet pipe (lower) burned my finger, outlet pipe (upper) was very hot.
This is what it's supposed to exhibit, right? Hot coolant goes in bottom, heat is extracted by blower, cooler coolant exits the top.
NOW what do I investigate?
This is what it's supposed to exhibit, right? Hot coolant goes in bottom, heat is extracted by blower, cooler coolant exits the top.
NOW what do I investigate?
AudiWorld Senior Member
Joined: Mar 2000
Posts: 1,777
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From: Lombard, Illinois
First CRL is a typo for CLR which is a de-liming product you can buy most anywhere.
Second, as long as the second pipe is not relatively cool, your heater core should be working correctly. The next step would be to check your heater doors on the interior. A real pain I'm sure. I have never done it and hope I never have to.
Good Luck!
Second, as long as the second pipe is not relatively cool, your heater core should be working correctly. The next step would be to check your heater doors on the interior. A real pain I'm sure. I have never done it and hope I never have to.
Good Luck!
AudiWorld Newcomer
Joined: Jul 2012
Posts: 9
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In the original post you mentioned the water pump. Have you done any checking on that? At idle the flow is pretty weak, but it should increase noticeably when you rev it up. The heater core bleed hole is a good place to check this, if you have someone rev it up while it's bleeding.
If it doesn't, maybe the water pump is damaged somehow? I think some of the early pumps had plastic impellers that could lose effectiveness without catastrophic failure, but I could be thinking of a different motor.
I don't think the 2.7 has an electric coolant pump other than the after-run pump. ??
As for mystery water loss, if it's leaking around one of the coolant temp sensors on the cross-pipe at the back of the heads, the coolant will drip on the hot manifolds and evaporate, leaving no visible liquid, but a strong coolant smell.
Maybe take a look at the whole heater circuit and see if there's a blockage outside of the heater core.
Good luck.
If it doesn't, maybe the water pump is damaged somehow? I think some of the early pumps had plastic impellers that could lose effectiveness without catastrophic failure, but I could be thinking of a different motor.
I don't think the 2.7 has an electric coolant pump other than the after-run pump. ??
As for mystery water loss, if it's leaking around one of the coolant temp sensors on the cross-pipe at the back of the heads, the coolant will drip on the hot manifolds and evaporate, leaving no visible liquid, but a strong coolant smell.
Maybe take a look at the whole heater circuit and see if there's a blockage outside of the heater core.
Good luck.
thank you
AudiWorld Senior Member
Joined: Aug 2009
Posts: 937
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there are three temp sensors in allroad (2.7). One on front radiator return line right in front of alternator and two in back of engine, inside hard metal pipe running from passenger to driver head. They sitting just before the pipe bends towards front and bolts to head, one each on each side of pipe.
All three use rubber o-rings to seal and are usually major pain in the butt to remove after baking for 10 years. spraying with pb-blaster and wiggling makes them to give eventually. Don't give up, just wiggle, spray, wiggle. PB Blaster penetrates rubber and makes it soft allowing the sensors to be eventually removed.
Replace o-rings and you are good to go.But make sure to order some U-clips too since the ones on sensors might break from age when you attempt to remove.
All three use rubber o-rings to seal and are usually major pain in the butt to remove after baking for 10 years. spraying with pb-blaster and wiggling makes them to give eventually. Don't give up, just wiggle, spray, wiggle. PB Blaster penetrates rubber and makes it soft allowing the sensors to be eventually removed.
Replace o-rings and you are good to go.But make sure to order some U-clips too since the ones on sensors might break from age when you attempt to remove.
AudiWorld Newcomer
Joined: Dec 2012
Posts: 2
Likes: 0
Mike
there are three temp sensors in allroad (2.7). One on front radiator return line right in front of alternator and two in back of engine, inside hard metal pipe running from passenger to driver head. They sitting just before the pipe bends towards front and bolts to head, one each on each side of pipe.
All three use rubber o-rings to seal and are usually major pain in the butt to remove after baking for 10 years. spraying with pb-blaster and wiggling makes them to give eventually. Don't give up, just wiggle, spray, wiggle. PB Blaster penetrates rubber and makes it soft allowing the sensors to be eventually removed.
Replace o-rings and you are good to go.But make sure to order some U-clips too since the ones on sensors might break from age when you attempt to remove.
All three use rubber o-rings to seal and are usually major pain in the butt to remove after baking for 10 years. spraying with pb-blaster and wiggling makes them to give eventually. Don't give up, just wiggle, spray, wiggle. PB Blaster penetrates rubber and makes it soft allowing the sensors to be eventually removed.
Replace o-rings and you are good to go.But make sure to order some U-clips too since the ones on sensors might break from age when you attempt to remove.
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