Water Pump Pulley Bolt

[ratwell]

Can someone please confirm the 10Nm torque for this bolt with left-hand thread?

https://parts.vw.com/p/Volkswagen__/...HT001163B.html

Water Pump Pulley Bolt.jpg

The torque value appears, I believe, in the 2011 A4/S4 Quick Reference (page 35) as "toothed belt drive gear" which seems to be a very literal translation from the original German.

Water Pump Pulley Bolt Spec.jpg

Also, where it says "(always replace)", I assume that Audi is referring to the bolt given its torque to yield spec and not the drive pulley itself?

Thanks.

[beatsageo]

yup, 10 + 90 is right

[Theiceman]

yup just helped someone with this last week . this is almost never done though as most guys leave the belt on and slip in the new pump. unless of course the project is replacing balance shafts.

[the-quattro-man]

I'm about to tackle this job replacing water pump as my car is nearing 85k miles. I don't have any water pump issue or leaks but just as PM. Is it recommended to replace this bolt or as already mentioned just leave belt and slip in new pump?

[Chillaxin]

Reuse Belt and slip in new pump.

[Theiceman]

vast majority just slip the pump from under the belt. this pump sees no real strain. I did the same and it was easy, just leave belt and pulley and bolt in place.

[ratwell]

Thanks for the replies.

The belt is supposed to last "a lifetime" but you have to wonder how many miles is too many.

The fan wheel attached to the water pump itself is designed to air cool the belt to extend its life:

EA888 2nd Gen Water Pump.jpg

I guess many people leave the belt in place mainly due of the hassle of replacing it including the limited space to access it.

[findalex]

I replaced my belt when I replaced the water pump because the kit came with it. Honestly, the old belt looked new, but then again, that's what they say about timing belts: It may look new, but it'll eventually be worn thin and snap at the worst time.

It is a major pain in the butt because it's hard to reach it and hard to get a good grip on the bolt. I bought a special socket because it's the closest to the factory tool without buying the special torque wrench. It was my first time, so I was really afraid of ruining a bolt that I couldn't see. And it definitely took more than 10 NM to remove it, so I was sweating bullets for a while.

Now that I've done it once, it's really not too bad. I'm sure there are mechanics that can do the entire job in 30 minutes, whereas it took me much longer because I was researching and buying various tools.

[ratwell]

From Rein:

Bulletin: CRP 050816 https://crpautomotive.com/wp-content...p-Tech-Tip.pdf

The problem: Pump has high failure rate.

Probable causes:

• Leakage caused by failing gaskets used to seal pump to engine or thermostat housing around the mounting bolts.
• Leakage caused by incorrect torque specs used during assembly.
• Leakage caused by thermostat misalignment.
• Gasket swelling originates from a cam girdle oil leak, which ultimately leaks past the manifold onto the pump.
• Incorrect balance shaft belt tension on the water pump creates excessive stress on the bearing, leading to premature pump failure.

Note: Proper torque of the bolt on the balance shaft belt should set the tension.

Reusing the old hardware and the old belt can lead to premature failures.



There's a lot here worthy of debate.

From Audi:

"The tension of the coolant pump drive belt is defined by the installation position of the coolant pump and cannot be adjusted."

Source: http://www.vaglinks.com/docs/ssp/VWU...FSI_Engine.pdf (Page 29)

So, isn't the belt going to stretch over time and require replacement?

[RPMtech147]

vast majority just slip the pump from under the belt. this pump sees no real strain. I did the same and it was easy, just leave belt and pulley and bolt in place.

How do you do it without bending the little "cooling" fins on the pump? I can sneak the belt on without loosening the bolt, but the pulley looks like crap with the fins bent all over the place. NM, you're saying you slip the pump into the belt then bolt pump down? Hmm. I'll have to try that. I'm always worried about the union to the oil cooler not seating correctly so I insert that end first.

[Theiceman]

I replaced my belt when I replaced the water pump because the kit came with it. Honestly, the old belt looked new, but then again, that's what they say about timing belts: It may look new, but it'll eventually be worn thin and snap at the worst time.

It is a major pain in the butt because it's hard to reach it and hard to get a good grip on the bolt. I bought a special socket because it's the closest to the factory tool without buying the special torque wrench. It was my first time, so I was really afraid of ruining a bolt that I couldn't see. And it definitely took more than 10 NM to remove it, so I was sweating bullets for a while.

Now that I've done it once, it's really not too bad. I'm sure there are mechanics that can do the entire job in 30 minutes, whereas it took me much longer because I was researching and buying various tools.

10nm +90 degrees is a fair bit of torque. you wont remove it with 10 n/m lol.

[Theiceman]

How do you do it without bending the little "cooling" fins on the pump? I can sneak the belt on without loosening the bolt, but the pulley looks like crap with the fins bent all over the place. NM, you're saying you slip the pump into the belt then bolt pump down? Hmm. I'll have to try that. I'm always worried about the union to the oil cooler not seating correctly so I insert that end first.

yes exactly hook the pump under then bolt it down . its a bit tricky as when you are putting the "other end" of the pump in place you have to slip in the tube to the oil cooler .. sil glide is a savior here on those orings. very satisfying when it all settles in place though.

[Theiceman]

oh and don't bet your life on you tube. bolt torque has zero to do with belt tension in this case , the pump pulley and and balance shaft pulley are at fixed distances apart this is what sets the belt tension ( which is actually very very low. ) the bolt torque is simple to stop the pulley spinning off the end. there is no debate, only opinions that are wrong.