Weird noise from upper tensioner pulley

[cobra]

I heard this noise coming from my engine bay. Using a screwdriver stethoscope I was able to pinpoint the noise to the upper tensioner pulley (the one mounted on the hydraulic tensioner). It sounds like a gurgling/grinding/rough sound and can be heard and felt. The crank, ps pump, idler, alternator, and water pump all sound silky smooth.

So I removed the belt and the tensioner pulley feels perfectly smooth when rotating it by hand. It has less than 5000 miles on it. There is no perceptible play and it feels frictionless!

I then started the engine (cold, only for 15 seconds) with the belt removed, and the sound was gone. So I know it's not coming from somewhere else nearby.


So... what the heck could this be? Should I replace the pulley anyway and hope it goes away? Is it possible the tensioner itself is making noise? It feels normal to me...

Opinions welcome.

[mpower22]

A lot of pulleys that are completely frictionless actually have dried out bearings that don't have much life left on them, so the fact that you have 5k was kind of surprising. Are you sure it's not the idler pulley that has 5k and maybe it was the tensioner that wasn't changed?

Also it depends if you changed the whole tensioner assembly or just the pulley. If the tensioner is original, it could have a hydraulic leak and that could be your cause from the additional movement, but a good tensioner doesn't move very easily, especially when just idling. Did you put a Chinese pulley on or brand name? Always try to find a good quality OEM one by a reputable brand. There's a lot of junk out there that uses company names like it's German made but not.

[cobra]

I had replaced the tensioner pulley as well as the idler. I did not replace the tensioner itself which looks like a little miniature shock. It feels fine to me in that it's got a lot of spring force and damping. The tensioner mechanism was not dancing around or doing anything out of the ordinary.

I used INA brand from fcp which is supposed to be oe.

I went ahead and ordered a replacement so I'll try it out and report back.

[sapote]

So I removed the belt and the tensioner pulley .

two belts or just mian belt?

Water pump bearings noise?

[cobra]

two belts or just mian belt?

Water pump bearings noise?

I removed both belts.
The water pump seems nice and quiet and smooth. It's also pretty new

[sapote]

I removed both belts.
The water pump seems nice and quiet and smooth. It's also pretty new

If removing both belts makes the noise disappeared, then one of the parts driven by the belts created the noise. Did you check the AC belt tensioner pulley?

All pulleys when spin by hand should not running freely with the rolling noise of the balls, but it should feel a little sticky by the grease.

[Boost]

I know you ruled it out already, but if you haven't physically checked, grab hold of the water pump/pulley and see if it wiggles around. Mine was making terrible noise on idle and all but went away when I took the fan clutch off and ran the engine cold with the belt still on. My water pump is the culprit; has a millimeter+ of play. Also pretty new, but the noise came about after the car sat for a couple years.

[cobra]

If removing both belts makes the noise disappeared, then one of the parts driven by the belts created the noise. Did you check the AC belt tensioner pulley?

All pulleys when spin by hand should not running freely with the rolling noise of the balls, but it should feel a little sticky by the grease.

Yes, I removed the AC tensioner belt. I was able to reproduce the noise with only the big accessory belt attached.
The pulley isn't dry feeling, it feels like a perfect bearing with grease.

I know you ruled it out already, but if you haven't physically checked, grab hold of the water pump/pulley and see if it wiggles around. Mine was making terrible noise on idle and all but went away when I took the fan clutch off and ran the engine cold with the belt still on. My water pump is the culprit; has a millimeter+ of play. Also pretty new, but the noise came about after the car sat for a couple years.

I did grab the water pump and I can feel the slightest amount of play, but when putting my 'mechanics stethoscope' against the WP it's perfectly silent. The loudest noise was when I put the tool against the inside of the tensioner pulley with the plastic cover removed.

[bigjae46]

A newer pulley should NOT spin freely. If you spin it by hand it should stop pretty quickly.

[cobra]

Update:

I got the new pulley on there and it's the same as before. I very closely examined it and it appears that the noise is coming from the tensioner where the pulley mounts. Perhaps "tapping" internally to the tensioner or at one of the bushings at the end of it as it adjusts to minor variations in the belt. I can see ever so slight movement there. What's the failure mode on one of these? When I rotate the tensioner with a wrench, I feel a lot of hydraulic resistance and spring force so I'm not sure if it's normal or failed.

I will remove it and play with it on the bench to see if there's something weird going on here.

[sapote]

Chirping cricket noise or continuous noise? Better do a self portrait using your vocal cord to recreate the noise in YT video and post the link

[sapote]

I think the tensioner arm pivot pin/shaft has too much plays from wear.

[cobra]

I think the tensioner arm pivot pin/shaft has too much plays from wear.

It's not a chirping or squealing. It's rather continuous and feels like a grinding.

[sapote]

It's not a chirping or squealing. It's rather continuous and feels like a grinding.

Grinding noise from the tensioner bracket? Not much moving parts on the bracket to make the noise. Maybe remove the bracket off the car and wiggle the parts around and look for plays.

[cobra]

Grinding noise from the tensioner bracket? Not much moving parts on the bracket to make the noise. Maybe remove the bracket off the car and wiggle the parts around and look for plays.

Yep going to do that. Will report back!