Thanks for the idea, just ordered one.

 

Watch the belt grooves closely while engine running. If that serp belt is at all off then they tend to be noisy. Also I have had some "cheap" belt made of not so good material make noise also. They can ride against one of the ribs. I have also tried a 6 groove on a 7 groove system. Also I have painted a pulley to see where the shiny part starts showing.

 

I replaced everything! My buddy yanked on the belt, on the tensioner side and let it go; "clunk" "you hear that! that means your belt is too long your tensioner is bottoming out. Your tensioner should stay at about the half way point. Note ALL the parts were brand new the the correct parts! Pull hard enough on the belt on the tensioner side to flex the tensioner let it snap back, if you hear a clunk your belt is too long (or more likely it's routed the wrong way) ! I just saved you hundreds of dollars and hours of time! Update! It turns out that I had the belt routed the wrong way but it still would work except when it was very cold. Next time I will check the shop manual first for the routing instead of watching some dude on Youtube put it on the wrong way.

 

Hello,
I have a Disco 2 V8 4.0L with ACE and recently I solved the annoying belt noise. In my case, the noise starts only with the engine cold and last about 10 minutes, after that the noise go off.

Trying to fix this problem I replaced everything, including the ACE pump and the noise remained the same. My last resource was measure the pulleys alignment with an aluminum bar and a blades feeler gauge, founding 1.4 mm of difference between the ACE and PAS (power assisted steering) pulley, so I added some washers as spacers in the ACE pulley trying to reduce to 0 this alignment difference, resulting in a full noise reduction.

How I got to this conclusion? After a lot of forums search, I found a common symptom, in most cases the noise comes after a PAS pump replacement with a remanufactured/repaired pump and, a couple of years ago, I disassembly my PAS pump for a seals replacement. In this opportunity I didn't have the belt noise problem, maybe because I was running with an old belt.

When you repair a PAS pump, it must be completely disassembled, including the axle, so when you reassembly the pump, in some cases the pulley could results displaced. In my case I didn't noticed it until now.

I hope this information will be useful for somebody.
Regards