Audi D3 A8 W12 water pump and serp belt tips (and near nightmare...)
07-21-2015, 10:52 PM
#1
AudiWorld Super User
Thread Starter
Audi D3 A8 W12 water pump and serp belt tips (and near nightmare...)
I recently posted about W12 coolant hoses and tips as part of a planned water pump change on my W12. That was here: https://www.audiworld.com/forums/a8-...oises-2886012/ I didn't really want to post on the water pump until I was all done with the job, ran down the noise in full that prompted the change, and had a successful post work start up to full operating temp and lots of varied motor revs, and then some regular driving.
It turns out the bearing noise that prompted the sudden hurry up on the water pump job was indeed the A/C pulley failing. I came across a rough bearing issue and some debris described in the last post, but didn't appreciate how bad it was. I will post on that in coming days, and stick to water pump here.
Likewise, I found coolant leaks twice before that made it very hard to know if it was the pump or not. I still don't honestly. Most of the time I was looking for an apparent tiny drip volume wise, not a stream. Time #1 I found a leak at the upper hose o ring seal and changed that. One of the pics below shows the o ring. #2 per the recent linked post is when I found the cracked T in a small hose in the same general area. When I did look over the finally removed water pump, I did find I could run tap water into one of the little blow out holes water pumps usually have to get water out of the bearing area and tell you it is headed south, and it would come out elsewhere. But the pump seems to have kind of a tiny semi circular channel cast into the pump with two exit holes so I can't be sure. The water that ran out showed some rust for fair number of seconds though (as in, not just momentary dirt or dust) which made me suspicious.
I'll save the general how to's or step by step on water pump changes. In Bentley, and on a W12 it's mostly common sense. Same pump was used in the forgotten VW W8 too. Instead some tips, and especially recovering from potential disaster:
1. The serp belt can be removed in two ways, with different pluses and minuses. If strictly from above, the intake has to be off to get the wrench in to the tensioner, the upper hose has to come off, and that means coolant needs to be at least partially drained to avoid a sudden flood. A 30mm large offset box end wrench is my tool of choice. Ebay China "quality" was fine. Much easier if from above, and a simple wrench turn frees belt. You can also do it from below, though it is sort of a mix. You can just barely wedge a breaker bar with a 30mm socket in there from above with only the front smog hose disconnected on one side. The offset box end doesn't work with the top coolant hose connected, plus the intake is sort of in the way of the wrench swing. With the breaker bar and a (large) 30mm socket stuck on the end, it is so tight you have to swivel the head by forcing it against the cooling fan as it swivels around and gets onto the tensioner. Then you need one person above applying force on the tensioner while you go underneath and get the belt off the A/C and power steering area. The breaker bar just stays in there the whole time until you put the belt back on. Having done it both ways (once w/ box end, twice w/ socket) I prefer the intake pull method overall, if you need to drain coolant and/or pull it anyway. As I've posted W12 intake pull is pretty easy, and a lot easier than my 4.2 experience. Socket method takes a helper while you go under to get belt off, and getting the socket in and out of there is not for the faint of heart. If I could find a bit shallower specialty socket instead of my std. Craftsman, it would help. You can't wrench from below BTW--various pulleys stick out too far for the offset box end, and the breaker bar ends up in the same space you need to free up the belt from the pulleys.
2. Water pump itself.
Pictures below:
It turns out the bearing noise that prompted the sudden hurry up on the water pump job was indeed the A/C pulley failing. I came across a rough bearing issue and some debris described in the last post, but didn't appreciate how bad it was. I will post on that in coming days, and stick to water pump here.
Likewise, I found coolant leaks twice before that made it very hard to know if it was the pump or not. I still don't honestly. Most of the time I was looking for an apparent tiny drip volume wise, not a stream. Time #1 I found a leak at the upper hose o ring seal and changed that. One of the pics below shows the o ring. #2 per the recent linked post is when I found the cracked T in a small hose in the same general area. When I did look over the finally removed water pump, I did find I could run tap water into one of the little blow out holes water pumps usually have to get water out of the bearing area and tell you it is headed south, and it would come out elsewhere. But the pump seems to have kind of a tiny semi circular channel cast into the pump with two exit holes so I can't be sure. The water that ran out showed some rust for fair number of seconds though (as in, not just momentary dirt or dust) which made me suspicious.
I'll save the general how to's or step by step on water pump changes. In Bentley, and on a W12 it's mostly common sense. Same pump was used in the forgotten VW W8 too. Instead some tips, and especially recovering from potential disaster:
1. The serp belt can be removed in two ways, with different pluses and minuses. If strictly from above, the intake has to be off to get the wrench in to the tensioner, the upper hose has to come off, and that means coolant needs to be at least partially drained to avoid a sudden flood. A 30mm large offset box end wrench is my tool of choice. Ebay China "quality" was fine. Much easier if from above, and a simple wrench turn frees belt. You can also do it from below, though it is sort of a mix. You can just barely wedge a breaker bar with a 30mm socket in there from above with only the front smog hose disconnected on one side. The offset box end doesn't work with the top coolant hose connected, plus the intake is sort of in the way of the wrench swing. With the breaker bar and a (large) 30mm socket stuck on the end, it is so tight you have to swivel the head by forcing it against the cooling fan as it swivels around and gets onto the tensioner. Then you need one person above applying force on the tensioner while you go underneath and get the belt off the A/C and power steering area. The breaker bar just stays in there the whole time until you put the belt back on. Having done it both ways (once w/ box end, twice w/ socket) I prefer the intake pull method overall, if you need to drain coolant and/or pull it anyway. As I've posted W12 intake pull is pretty easy, and a lot easier than my 4.2 experience. Socket method takes a helper while you go under to get belt off, and getting the socket in and out of there is not for the faint of heart. If I could find a bit shallower specialty socket instead of my std. Craftsman, it would help. You can't wrench from below BTW--various pulleys stick out too far for the offset box end, and the breaker bar ends up in the same space you need to free up the belt from the pulleys.
2. Water pump itself.
a. The total nightmare scenario: one of those "Art of Engineering" seemed like a good idea at the time M8 triple square bolts they use strips out. Still used on current Audis BTW from the parts listings... In my case, the one on the bottom. That one has a metal oil line that runs just below it, so close that many M8 tools get forced into an offset and then its a set up for a stripped bolt. Or, the tool you have is sub par (say, a set from Lisle commonly sold at stores...), plus it has a large half inch hex type head. Another set up for the issue. Drop kicked that "tool" right into my garage trash while muttering a few words.
b. Net, to settle on the right tool--having ordered sequentially from Amazon day over day until I got the right tool to both get out the stripped one and get at it correctly--what you really need/want for this troublesome bolt is a M8 screw tip you mount into a ¼" drive set up with a stubby extension. Alternately, an M8 head with some slightly extended tips to clear that oil line interference. The ¼ drive socket that worked for me is a very short one branded by Bosch (the tool part, not the automotive) and on Amazon for about $8; essentially I used it like a drive extension. Most ¼" drive bit holders are over 2" long, that one is only about half that. Critical with the tip that sticks out, clearing the oil tube without an offset angle, yet short enough to get a wrench square on it. Pounding it home, enough good and bad experiences w/ triple square now to know the bit has to fit precisely and the tool has to come straight on to the bolt and go in full depth.
c. As far as how to recover, I tried lots of stuff. Tried a fresh M8 tip and drove it in hard. That actually got a second one out that was chewed up where I knew to stop until I got a different tool, but not the bottom nightmare one. I thought about going up to a bigger size of something, but in triple square stuff, it's too big a jump to next size/M10. I looked at Torx too, but T30 is about the same as M8 and I didn't get any purchase. T40 is again just too big to force in there, especially when you literally have about 2-1/2" max on a deep reach to apply any force or try to tap on it with something. I got a T35 that is used for some oddball American car stuff via Amazon, but it came with a ½" drive set up that was a non starter again with that immovable oil tube which runs through a hole in the torque mount area down to the oil cooler and filter stuff.
d. The successful tools--a little hobbyist 90 degree drive I hooked to my Makita cordless drill. The hobby set up uses ¼ drive drill bits, they include several, and they sell some other ones too. Standard (and inexpensive) Amazon stuff. Reviews said plastic gears, may break quickly, etc., but it held up for me and was just the right size to get in there unlike all the other too long and/or too fat stuff I had been getting via Amazon until that one. That allowed me to drill it out, basically as far as I wanted. But I realized not to go too deep that would either drill the whole head off and leave me with a threaded broken off stud mess coming out the block, or that it might shear with a similar result. Again, "Art" you didn't think this parts choice through sehr gut for real world extended life service rather than just Hungarian motor plant automated assembly floor... As I drilled, I ended up sizing up one in the classic easy out (or E-Z out or various other names) I succeeded with. I tried those all-in-one drill and screw extractor things they have at the hardware store (and late night TV...), but it had too much angle to the tip to really dig in. Instead, the Hanson EX-5 with the ¼" hole size bit from the hobby tool did the trick; the easy out says use 19/64, but with the hobby stubbies it's either ¼" or 5/16". Turns out that EX-5 was part of a set I've had in my tool box for years. I think it was the same one that served duty pulling out another of Art's stupid triple square bolts that hold in the wheel bearing cartridges back to my C5 and most any Audi now with the aluminum steering knuckle set up. That EX-5 size is hefty enough that it isn't going to snap off with anything below extreme torque from a ½" extended bar, and I was just using ¼" stuff here, and in that case a simple open end wrench on the back square of the tool.
And, once again still no front clip or front bumper cover pull ever on D3 or prior C5 4.2. This one was getting close to saying Uncle though...b. Net, to settle on the right tool--having ordered sequentially from Amazon day over day until I got the right tool to both get out the stripped one and get at it correctly--what you really need/want for this troublesome bolt is a M8 screw tip you mount into a ¼" drive set up with a stubby extension. Alternately, an M8 head with some slightly extended tips to clear that oil line interference. The ¼ drive socket that worked for me is a very short one branded by Bosch (the tool part, not the automotive) and on Amazon for about $8; essentially I used it like a drive extension. Most ¼" drive bit holders are over 2" long, that one is only about half that. Critical with the tip that sticks out, clearing the oil tube without an offset angle, yet short enough to get a wrench square on it. Pounding it home, enough good and bad experiences w/ triple square now to know the bit has to fit precisely and the tool has to come straight on to the bolt and go in full depth.
c. As far as how to recover, I tried lots of stuff. Tried a fresh M8 tip and drove it in hard. That actually got a second one out that was chewed up where I knew to stop until I got a different tool, but not the bottom nightmare one. I thought about going up to a bigger size of something, but in triple square stuff, it's too big a jump to next size/M10. I looked at Torx too, but T30 is about the same as M8 and I didn't get any purchase. T40 is again just too big to force in there, especially when you literally have about 2-1/2" max on a deep reach to apply any force or try to tap on it with something. I got a T35 that is used for some oddball American car stuff via Amazon, but it came with a ½" drive set up that was a non starter again with that immovable oil tube which runs through a hole in the torque mount area down to the oil cooler and filter stuff.
d. The successful tools--a little hobbyist 90 degree drive I hooked to my Makita cordless drill. The hobby set up uses ¼ drive drill bits, they include several, and they sell some other ones too. Standard (and inexpensive) Amazon stuff. Reviews said plastic gears, may break quickly, etc., but it held up for me and was just the right size to get in there unlike all the other too long and/or too fat stuff I had been getting via Amazon until that one. That allowed me to drill it out, basically as far as I wanted. But I realized not to go too deep that would either drill the whole head off and leave me with a threaded broken off stud mess coming out the block, or that it might shear with a similar result. Again, "Art" you didn't think this parts choice through sehr gut for real world extended life service rather than just Hungarian motor plant automated assembly floor... As I drilled, I ended up sizing up one in the classic easy out (or E-Z out or various other names) I succeeded with. I tried those all-in-one drill and screw extractor things they have at the hardware store (and late night TV...), but it had too much angle to the tip to really dig in. Instead, the Hanson EX-5 with the ¼" hole size bit from the hobby tool did the trick; the easy out says use 19/64, but with the hobby stubbies it's either ¼" or 5/16". Turns out that EX-5 was part of a set I've had in my tool box for years. I think it was the same one that served duty pulling out another of Art's stupid triple square bolts that hold in the wheel bearing cartridges back to my C5 and most any Audi now with the aluminum steering knuckle set up. That EX-5 size is hefty enough that it isn't going to snap off with anything below extreme torque from a ½" extended bar, and I was just using ¼" stuff here, and in that case a simple open end wrench on the back square of the tool.
Pictures below:
The o ring used in any D3 main hose connection--last thing you can make out toward the inside, with the slight tan cooling system type deposit particles in the 6 o'clock position. Sold as inexpensive bit parts by dealers; I now change any time I pull a main hose.
The specific situation I found in the water pump area--notice the coolant pinkish deposits at one place--could have been any of pump, that small hose leak per prior post, or the main hose that sits directly above (even though I tried to clean up after I changed that o ring). Picture was shot through the hinge opening area, where you can get a pretty direct view on a W12.
Easy out tool as positioned where the bolt from Hell was right after I cracked it and breathed big sigh of relief.
The savior tools pictured with the old water pump, the stripped out bolt, and another one that came out clean showing that Art of undersized, overly finicky design, coupled with that oil pipe you can see in the preceding Easy out picture
The specific situation I found in the water pump area--notice the coolant pinkish deposits at one place--could have been any of pump, that small hose leak per prior post, or the main hose that sits directly above (even though I tried to clean up after I changed that o ring). Picture was shot through the hinge opening area, where you can get a pretty direct view on a W12.
Easy out tool as positioned where the bolt from Hell was right after I cracked it and breathed big sigh of relief.
The savior tools pictured with the old water pump, the stripped out bolt, and another one that came out clean showing that Art of undersized, overly finicky design, coupled with that oil pipe you can see in the preceding Easy out picture
Last edited by MP4.2+6.0; 07-22-2015 at 08:08 AM.
07-22-2015, 03:28 AM
#2
AudiWorld Super User
Nightmare is right. Thank goodness you were able to get it out.
I have a 3/8" drive 90° Bosch electric drill on standby for stuff like this. Had to use it once on my Son's TT for a snapped olt during intake manifold removal. This was needed to replace a brittle rubber emission hose (Part was a cozy $225.00 with a nice discount) contraption.
I have a 3/8" drive 90° Bosch electric drill on standby for stuff like this. Had to use it once on my Son's TT for a snapped olt during intake manifold removal. This was needed to replace a brittle rubber emission hose (Part was a cozy $225.00 with a nice discount) contraption.
07-22-2015, 08:00 AM
#3
AudiWorld Super User
Thread Starter
Nightmare is right. Thank goodness you were able to get it out.
I have a 3/8" drive 90° Bosch electric drill on standby for stuff like this. Had to use it once on my Son's TT for a snapped olt during intake manifold removal. This was needed to replace a brittle rubber emission hose (Part was a cozy $225.00 with a nice discount) contraption.
I have a 3/8" drive 90° Bosch electric drill on standby for stuff like this. Had to use it once on my Son's TT for a snapped olt during intake manifold removal. This was needed to replace a brittle rubber emission hose (Part was a cozy $225.00 with a nice discount) contraption.
Thread
Thread Starter
Forum
Replies
Last Post
mart_o_rama
A8 / S8 (D2 Platform) Discussion
15
06-07-2008 06:48 PM
TT911
TT (Mk1) Discussion
7
06-07-2007 09:25 PM
Vladimir
A4 (B5 Platform) Discussion
0
05-24-2004 11:55 AM
caddidle
A4 (B5 Platform) Discussion
8
07-08-2003 06:00 AM