4.8i a/c belt squeaking

[andrewwynn]

Originally Posted by Cyrix2k

I just ordered a used one with 64k miles on it. We'll see if that fixes it. I got the X5 all warmed up and looked at the pulley and I think it does have a very slight wobble to it.


Yeah. I knew some of them were made like this but always thought failure was extremely rare. On older vehicle where the crank position sensor actually reads the crank pulley, the outside of the pulley can slip and throw the reading off.

I think it's pretty rare this is only the second time I've seen come up on xo. I'm close to 6700 posts & pretty common posting to most threads

[Cyrix2k]

Whelp, the balancer came in and that wasn't it. I've had quite the evening... went out for test drive after installing the balancer, shredded the a/c belt (not sure what happened yet, maybe I had it a rib off by accident) and then ran over a deer that the vehicle in front of me hit. Thankfully there doesn't seem to be any damage, just deer fur in various parts of the undercarriage.

At this point I know the noise isn't the a/c since it still makes the noise with the belt off. I again spun all the accessories by hand and they feel fine to me. The water pump has a very slight amount of play to it. In my opinion, it feels fine and comparable to one of the new idlers I installed. When I spin it, it feels smooth and doesn't make any noise. I'm at a loss at this point. Oh, and if it matters it was quiet for about the first 10 minutes. It only started making noise once the oil was up to temp - over 200 degrees.

[andrewwynn]

Does your engine have a mechanical clutch? Those engage when warm.

[Cyrix2k]

You mean for a mechanical fan? No, it's electric only.

[andrewwynn]

Yep what I meant and that exempts that from the squeak.

[Cyrix2k]

The saga continues. I decided to replace the water pump along with all the older hoses I could find. Found the coolant transfer pipe behind the water pump RTV'd in place and ended up leaving it like that since I didn't have the fix kit, got the new water pump and thermostat installed and it *still* squeaks. Also, I threw a new A/C belt on and as soon as I start the X5, it pulls forward on the A/C pulley by one rib so more investigation is needed here. I assume this has to do with me replacing the pulley in the a/c pulley itself. At this point I assume the problem has to be vacuum related or internal to the engine...

[andrewwynn]

The belt moving suggests alignment problem with the tensioner. Did you run the car no belts to determine if the squeak is from belt driven accessory?

[Cyrix2k]

Originally Posted by andrewwynn

The belt moving suggests alignment problem with the tensioner. Did you run the car no belts to determine if the squeak is from belt driven accessory?

I think this alignment problem is self-inflicted lol (it happened after I replaced the bearings/tensioner/crank pulley). I can look at the tensioner but it's a pretty simple design and appears to be in the correct location. The A/C belt on mine only drives the a/c, everything else runs on a main serpentine belt. I was driving it around with the a/c belt off and the squeak is still there so it's clearly not a/c related. In terms of running it with no belts at all, yes I did and it was quiet. The problem is that it's quiet *with* the belt on too until the oil gets up to temp. It took over 30 mins at idle for the noise to start to come back yesterday and I can't run it that long without a belt since the water pump is belt driven I need to take the belt off after it's hot but I've been afraid of breaking a hose and scalding myself with hot coolant.

[andrewwynn]

This is sounding like harmonic balancer. I didn't get the memo about only when warm.

Two examples of "belt like squeak" sound but only when warm ended up being harmonic balancer on XO

To test: get car warmed up and squeaking and then remove belt and see if it goes away.

Search for the two threads using advanced and "harmonic balancer" in the content. Two in the past year on xo.

You can also use an app like FFT to listen using earbud microphone so you can home in on the source.

[Cyrix2k]

Originally Posted by andrewwynn

This is sounding like harmonic balancer. I didn't get the memo about only when warm.

Two examples of "belt like squeak" sound but only when warm ended up being harmonic balancer on XO

To test: get car warmed up and squeaking and then remove belt and see if it goes away.

Search for the two threads using advanced and "harmonic balancer" in the content. Two in the past year on xo.

You can also use an app like FFT to listen using earbud microphone so you can home in on the source.

Yeah, I replaced that already (granted, it was used)!

Things I've replaced:

• Every belt tensioner & idler pulley
• Both belts with Continental belts. Twice.
• A/C bearings in the A/C pulley (A/C known to not be the problem)
• Crank hub/harmonic balancer
• Water pump with a new Graf brand water pump

I also replaced the front CCV when I first bought the X5 just because it was old. I pulled and cleaned the water pump pulley thinking it maybe had dirt between it and the water pump hub leading to a misalignment. It's clean now. I cleaned the replacement crank pulley as well. I have a video of the squeak noise I'll post later.


Thanks for your help!