Aux Pump Replacement: Mission Accomplished

hewtown · 05-07-2012, 08:27 PM

2001 A6 2.7T APB

Finally finished the aux coolant pump replacement today. It was quite the adventure... took me maybe 6-8 hours of actual work (I was very slow, steady, and meticulous) but many more hours researching the job and related systems, mostly right here on audiworld.

This job was my first experience working closely within any engine, much less a 2001 Audi engine. So...I am quite the newb, but beginning to earn my stripes.

I followed Truewit's tech article, and BaysideRS4's post (http://forums.audiworld.com/showthre...ight=baysideS4) They were both very accurate, and absolutely invaluable to me.

Here's a couple pics. First with everything disconnected and the intake manifold propped up with a spray paint can. Second you can see just how blown-out the pump was, and the carnage it wreaked down there.

Main point of this post: THANKS to all on Audiworld who helped me do this job. This is a great community, and I really appreciate having it as a resource. Audiworld continues to save me big $$$ with my Audi maintenance and repairs. THANKS EVERYONE!

jseklund · 05-09-2012, 07:58 AM

Did I miss something? What's with the green coolant?

Good job on the replacement...get rid of the green coolant if you haven't already- it can cause problems elsewhere...

hewtown · 05-09-2012, 06:45 PM

Quote:

Originally Posted by jseklund

Did I miss something? What's with the green coolant?

Good job on the replacement...get rid of the green coolant if you haven't already- it can cause problems elsewhere...

Thanks... Yeah not sure how/when the green stuff got into the system... could have been the local indy shop when they flushed the coolant after a timing belt job 2 years ago. Could have been me adding green to the G12 as my Aux Pump slowly leaked over the last 6 months. Probably the latter, as I am/was a dumba$$ and still learning. Either way it is 100% green now after much leaking.

At any rate, I know I need to switch it out G12 ASAP. There's a lot of discussion and debate on how to do this properly, remove trapped air etc. Could you (or someone) point me to a tried and true method that you agree with? Also please note: I have had the "no heat at idle" issue for a long time. If you had tips on how to maybe fix that during the flush I would appreciate it.

Truewit · 05-10-2012, 08:48 AM

Your pictures and post brought back fond memories!!! Fortunately, I haven't had to get back and replace mine since I did it a few years ago -- but I have a spare on hand just in case.

jseklund · 05-10-2012, 12:24 PM

Well, there is actually a write-up somewhere from someone who replaced the G12 with regular coolant. The theory is that if you flush out ALL of the G12, you can use regular coolant and you should be fine. I'm not recommending it, but I'm not saying it won't work either. It looks like A LOT of work to flush the system, and I believe the guy had to do about 10-15 flushes before the water came out perfectly clear and was ready for the green coolant.

The issue is that the two coolants mixing together causes issues. Crud forms, seals may be deteriorated, etc.

You're going to have to flush the crap out of the system to be sure it is clean now either way - so in theory you could just go green. I don't see a real benefit though, since the G12 isn't really much more expensive from the dealer than the regular green stuff.

I can't seem to find the write-up, but I'll look when I have more time or maybe someone else knows where to find it.

As for getting the air out - there are three bleed points. In the back of the engine, there is a pipe that is bolted to both heads (where the temp sensors are). There is a hose that comes off the overflow resevoir and goes down to a shaft on this pipe. That shaft screws into the pipe and can be unscrewed to let air out. You bleed from that until you get no air.

Then, you move to the front of the engine, to the right of the throttle body and down there is a bolt that you can use a hex socket to unscrew - that's your second bleed point.

The final bleed point is where the pipes go into the firewall. There is a rubber hose that goes over the top pipe. You need to pull this back far enough to let coolant come out of the small hole at the top of the hose. Chances are, the hose will be stuck on so tight it will take MUCH strength to get the hose off. I take a small pick with a 90 degree bend and slide it around the inside of the rubber to break it free of the pipe and it is still not easy. Keep working it. Once it's free, it will slide on and off easily.

Even doing this, there can be persistant air pockets that take a lot of work to get out...keep at it.

SloopJohnB@mac.com · 05-10-2012, 12:59 PM

OK, now that you've done it this way, do you think you could have done it by disconnecting the electric connector, releasing the hose at the back and the front and pulling the hose/pump/hose assembly out the front or the back? Without removing/propping up the intake manifold, etc.?

hewtown · 05-10-2012, 02:35 PM

Quote:

Originally Posted by Truewit

Your pictures and post brought back fond memories!!! Fortunately, I haven't had to get back and replace mine since I did it a few years ago -- but I have a spare on hand just in case.

Hey, thanks again for your awesome Tech Article. Good to hear it's holding up for you. One question: you don't mention replacing the two hoses connected to the pump...did you? If not, I'm really glad to hear those are holding up as well.

I myself did not replace them. First of all, I had trouble getting them loose (though I didn't try too hard). Secondly, they looked to be in pretty good shape despite the pump they were connected to.

hewtown · 05-10-2012, 02:44 PM

Quote:

Originally Posted by jseklund

Well, there is actually a write-up somewhere from someone who replaced the G12 with regular coolant. The theory is that if you flush out ALL of the G12, you can use regular coolant and you should be fine. I'm not recommending it, but I'm not saying it won't work either. It looks like A LOT of work to flush the system, and I believe the guy had to do about 10-15 flushes before the water came out perfectly clear and was ready for the green coolant.

The issue is that the two coolants mixing together causes issues. Crud forms, seals may be deteriorated, etc.

You're going to have to flush the crap out of the system to be sure it is clean now either way - so in theory you could just go green. I don't see a real benefit though, since the G12 isn't really much more expensive from the dealer than the regular green stuff.

I can't seem to find the write-up, but I'll look when I have more time or maybe someone else knows where to find it.

As for getting the air out - there are three bleed points. In the back of the engine, there is a pipe that is bolted to both heads (where the temp sensors are). There is a hose that comes off the overflow resevoir and goes down to a shaft on this pipe. That shaft screws into the pipe and can be unscrewed to let air out. You bleed from that until you get no air.

Then, you move to the front of the engine, to the right of the throttle body and down there is a bolt that you can use a hex socket to unscrew - that's your second bleed point.

The final bleed point is where the pipes go into the firewall. There is a rubber hose that goes over the top pipe. You need to pull this back far enough to let coolant come out of the small hole at the top of the hose. Chances are, the hose will be stuck on so tight it will take MUCH strength to get the hose off. I take a small pick with a 90 degree bend and slide it around the inside of the rubber to break it free of the pipe and it is still not easy. Keep working it. Once it's free, it will slide on and off easily.

Even doing this, there can be persistant air pockets that take a lot of work to get out...keep at it.

Thanks for the detailed post on how to do a bleed. I'll take any further tips on the full on flush though.

What do you think about a Heater Core Flush? I found the Tech Article by TristanP, but it's for an A4. Haven't researched in detail yet, but looks like the A6 heater core hose anatomy is different. Would like to try this since I have a sneaking suspicion part of the problem is a clogged/gunky heater core.

hewtown · 05-10-2012, 02:52 PM

Quote:

Originally Posted by SloopJohnB@mac.com

OK, now that you've done it this way, do you think you could have done it by disconnecting the electric connector, releasing the hose at the back and the front and pulling the hose/pump/hose assembly out the front or the back? Without removing/propping up the intake manifold, etc.?

Heck no I couldn't have done it without taking the manifold up. I honestly don't see how those guys did it without breaking it all down...there's just so little room. Hell, I couldn't even see the pump or identify it's hoses until I got the manifold up.

Secondly, there was a lot of leaked coolant down there that needed to be cleaned up. This certainly wouldn't be possible without removing the manifold.

Thirdly, in retrospect, disconnecting everything and getting down there wasn't really that bad. I feel when/if I have to give it another go, I'll be able to do so in just a couple hours. An experienced tech with the right tools already in his garage could do it very quickly I'm sure.

Truewit · 05-10-2012, 05:09 PM

No, I didn't replace the hoses -- they were in pretty good shape (the car was only a few years old then) so there didn't seem to be any point. When I embarked on the project I'd picked up some extra tubing equipped with a bend or two intending to relocate the pump to afford easier access in the event of a recurrence. After reviewing the layout with the intake manifold off, though, there just didn't seem to be any suitable alternative, so I gave up and left things as they were. Fortunately, I haven't had to redo it. As I mentioned in my piece, some key culprits in the leaking were the spring-type clamps that were originally installed. Anyway, glad to learn that everything worked out for you and my write-up was a help.

Cheers.

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05-09-2012, 07:58 AM	#2
jseklund AudiWorld Senior Member Garage is empty, add now Join Date: Feb 2009 Posts: 777	Did I miss something? What's with the green coolant? Good job on the replacement...get rid of the green coolant if you haven't already- it can cause problems elsewhere...

05-10-2012, 08:48 AM	#4
Truewit AudiWorld Member Garage is empty, add now Join Date: Feb 2005 Posts: 118	Your pictures and post brought back fond memories!!! Fortunately, I haven't had to get back and replace mine since I did it a few years ago -- but I have a spare on hand just in case.

05-10-2012, 12:24 PM	#5
jseklund AudiWorld Senior Member Garage is empty, add now Join Date: Feb 2009 Posts: 777	Well, there is actually a write-up somewhere from someone who replaced the G12 with regular coolant. The theory is that if you flush out ALL of the G12, you can use regular coolant and you should be fine. I'm not recommending it, but I'm not saying it won't work either. It looks like A LOT of work to flush the system, and I believe the guy had to do about 10-15 flushes before the water came out perfectly clear and was ready for the green coolant. The issue is that the two coolants mixing together causes issues. Crud forms, seals may be deteriorated, etc. You're going to have to flush the crap out of the system to be sure it is clean now either way - so in theory you could just go green. I don't see a real benefit though, since the G12 isn't really much more expensive from the dealer than the regular green stuff. I can't seem to find the write-up, but I'll look when I have more time or maybe someone else knows where to find it. As for getting the air out - there are three bleed points. In the back of the engine, there is a pipe that is bolted to both heads (where the temp sensors are). There is a hose that comes off the overflow resevoir and goes down to a shaft on this pipe. That shaft screws into the pipe and can be unscrewed to let air out. You bleed from that until you get no air. Then, you move to the front of the engine, to the right of the throttle body and down there is a bolt that you can use a hex socket to unscrew - that's your second bleed point. The final bleed point is where the pipes go into the firewall. There is a rubber hose that goes over the top pipe. You need to pull this back far enough to let coolant come out of the small hole at the top of the hose. Chances are, the hose will be stuck on so tight it will take MUCH strength to get the hose off. I take a small pick with a 90 degree bend and slide it around the inside of the rubber to break it free of the pipe and it is still not easy. Keep working it. Once it's free, it will slide on and off easily. Even doing this, there can be persistant air pockets that take a lot of work to get out...keep at it.

05-10-2012, 12:59 PM	#6
SloopJohnB@mac.com AudiWorld Super User 2002 Audi S6 Join Date: Oct 2002 Posts: 4,132	OK, now that you've done it this way, do you think you could have done it by disconnecting the electric connector, releasing the hose at the back and the front and pulling the hose/pump/hose assembly out the front or the back? Without removing/propping up the intake manifold, etc.?

05-10-2012, 05:09 PM	#10
Truewit AudiWorld Member Garage is empty, add now Join Date: Feb 2005 Posts: 118	No, I didn't replace the hoses -- they were in pretty good shape (the car was only a few years old then) so there didn't seem to be any point. When I embarked on the project I'd picked up some extra tubing equipped with a bend or two intending to relocate the pump to afford easier access in the event of a recurrence. After reviewing the layout with the intake manifold off, though, there just didn't seem to be any suitable alternative, so I gave up and left things as they were. Fortunately, I haven't had to redo it. As I mentioned in my piece, some key culprits in the leaking were the spring-type clamps that were originally installed. Anyway, glad to learn that everything worked out for you and my write-up was a help. Cheers.