Harmonic balancer wobble/Belt squeel/ Belt slips
 

Hi,

chevrolet express 2500 2015 here.

I've noticed recently that my harmonic balancer is wobbling. I just bought the vehicle and don't think it did that when I bought it. I did just change the belt and the tensioner so not sure if that has anything to do with it. The harmonic balancer wobble looks like this, another guy posted this.


That guy posted on this forum so you guys might want to go leave a comment and let him know. It looks the exact same on mine. Also on mine there is occasional belt squeel, and I can actually SEE the belt slip SOMETIMES. I can hear squeeling when ACCELERATING and because I've been under the van when it's idling i've seen what looks like the belt SLIP for a second. The other day when it was wet and cold the belt was squeeling a little bit more like chirping , but I can almost crack THAT up to all the rain that been hitting it.

I have to wonder if the tension is correct if my new tensioner was somehow defective. I've felt the tension in the new belt and it seems a little low. I am able to turn the belt a half turn and then maybe a 1/4 turn past that. The AC belt is on much tighter. This van has the separate AC belt. I've watched the AC belt and it seems to wobble too though I do not know if that is a big deal because it's in grooves on both sides and it's a special kind of stretch belt. Maybe this is all normal?

So how do I know if these automatic tensioners are working properly? and is it possible the harmonic balancer might've damaged by a belt maybe too loose, with the aC belt pulling too much tension? Are these two belts suppose to exert equal amounts of tension?

That video doesn't really look to be wobbling to me.
There should be two marks on a tensioner and a pointer/line should be between the two marks. What was the part number on your belt? I just put on new belts, idler pulley and tensioner. I'll have to dig up the part numbers but it was a green HD belt, that was a few mm shorter than the old belt and was very tight going on (I almost couldn't get it on). I got the stupid tool for the stretch belt and it didn't work. I have a 2015 w/ 6.0l.

From my understanding the part number breaks down to:
6= number of ribs
2365 = length in mm so the green one is 2mm shorter that made it very hard to get back on.
https://cimg4.ibsrv.net/gimg/chevrol...89ccecbdec.jpg

The tool that I got was read anodized and didn't work. This tool that comes with this belt looks like it would work. I ended up not even doing the zup-tie method and just used my hands. First stretch belt I've done. Didn't seem too hard, but the 2013 directions from Charm didn't work. No need to remove the wiring. No need for the tool, just hold it and turn the crank pulley to walk it on.

https://www.rockauto.com/en/moreinfo...308860&pt=8900

HEy here is this video. The very beginning shows exactly what my harmonic balancer looks like at idle


In the video, it says I need to replace it. This is not normal. But is it? My belt chirps when accelerating but is pretty quiet at idle.

I can't see anything in that video. How much is that guy getting paid to say that you need to replace your harmonic balancer?

Slipping belts is a bad thing. You need to fix that. If you take the belt off do all the pullies spin smoothly without making noise?Does it slip with the AC off? Do you have an indicator that you can measure the run out on the belt grooves with? They are cast. The cast areas often appear to wobble because they are not machined concentric but it should be all balanced together. The rubber can de-bond from the hub and or outer ring. You can put a mark on it to see if it moves.

Which belt is slipping? Is your tensioner within the 2 marked limits? What part number belt did you use? I.e. what length?

THIS BELT IS THE SERPENTINE BELT, not the AC ONE, though that one is also bouncing hardcore like in the video at post above
1) I took off the belt when replacing the water pump and I am pretty sure I checked all pulleys, but maybe not.
2) No difference with aC on or off, noise occurs
3) I don't have an indicator
4) yeah I getcha about the cast areas, BUT the AC belt moves quite a bit
5) put a mark on the hub and outer ring... I guess I can try and figure that out. Is the pulley two pieces then?

The serpentine belt sounds like it's slipping sometimes. It's very odd. The tensioner doesn't have any marks. I used the GM OE made in japan belt, bought off RA. IDK the length atm.

3) Got the picture below from RockAuto and put some blue arrows to show the min and max tension lines that the other line below on the moveable side needs to be between. Different companies make these look different but tell the same story.
https://www.rockauto.com/en/moreinfo...08860&pt=11659

https://cimg1.ibsrv.net/gimg/chevrol...da6b69c3c2.jpg
5) Yes it's 2 pieces. Also called the harmonic balancer. The outer ring is held to the inner hub with rubber. When the rubber goes bad it can separate causing them to not stay in alignment and go out of balance. Of course this rubber slipping could also make a squeel. I don't think I've ever seen one go bad. Some Amazon reviews mention it slipping.

1) Got your pic. GOod pic. I didn't know those lines meant anything at all. It all makes sense now. How did I not know this and this secret was kept from me by AC DELCO? Yeah it is in between those lines

2) I put a mark on it and not sure if I may have not drawn the line straight but when I looked at the front of the balancer the line was about a millimeter off, the mark I put on the rear of the balancer (side facing the rear of the vehicle) hadn't moved at all. All done with a blue sharpie.

I'll keep tabs on it, now that I know it's a two piece part, the rubber part looked a little funky. it didn't look broken or worn though, hard to explain.