Belt Squeal after new belt and pulleys.

Very frustrating.

Serpentine belt fell off while driving. Limped home.

Idler pulley was noisy and scratchy, and the tensioner pulley was completely seized.

Purchase new belt, idler and tensioner pulley. All aftermarket, auto zone duralast. Installed new parts and now it squeals.

Pulleys are of correct sizes/diameters.

Pulleys are perfectly aligned.

Belt is new.

Could it be a dust/dirt issue? Only thing I can point to now. I did see lots of dust and some supertiny belt chunks coming off the old pulleys when I installed the new parts.

At first the squeal was constant... now its on startup. No squeal on idle. But always squeal upon applying throttle, and squeals while driving. Sometimes it's a chirp chirp chirp.

Please help. I have searched and searched, and tripled checked.

 

Tensioner pulley has the job of keeping tension on the pulley.

Did you replace the tensioner pulley, or the tensioner assembly with the pulley?

If the tensioner itself isn't properly tensioning the belt, it's gonna squeal.

 

Could be the culprit then. I replaced just the tensioner pulley itself. Not the entire assembly.

Prior to the belt slipping off this truck never squealed a day in its life, given that could we exclude the tensioner spring?

All I did was install new pulley and tightened it up well. Nothing extreme but solidly tight.

Is there a way I can add more tension while the truck is running as someone revs to see if its a tension issue?

 

Sounds like the tensioner assembly. If you put a wrench on it does it snap back quickly or does it slowly come back?

 

Its very tight. When I applied the ratchet it definitely took some strong force to get it to move all the way. I never relieved tension and let go to see it snap back like you mentioned but it was definitely strong enough to pull back on me with good force. Im pretty sure it would snap back if I did. I'll give it a try though.

 

Way back when I had a 1st gen, the belt squealed when cold after the change. Saw something on the older tundra forum that said to reinstall the belt running the opposite direction. Can't say why, but it did work for me.

 

What does that mean? Flip the belt inside out or route it a different way?

I did make sure the belt matches the diagram under the hood

 

Watch which direction the belt rotates. Get a sharpie and draw an arrow for reference. Then remove and replace the belt so that it rotates in the opposite direction.

 

Ahh I see. Going to try a couple of things and report back.

Thank you all

 

I maybe missed where you gave us any indication about what year, cab type, V6 or V8, 2WD or 4WD, etc your truck is.

But that said: https://www.tundras.com/threads/so-you-wanna-buy-just-bought-a-1st-gen-tundra-eh.115928/

That thread. It’s our community knowledge base. In 2nd reply, note there is a load of TSBs, one of which covers a condition of squealing at cold starts for our trucks. If I recall, it’s a defect in the factory tensioner pulley assembly itself, but not knowing your year I can’t say if your truck is impacted (details matter, we have a “Vehicle One-Line Description” in your user profile / personal details to help members help you). Toyota changed the design a few years in, moved to a smaller pulley if I recall, and slightly changed the position as a result, due to said issue.

Why would it start suddenly after the failure you saw and changing the pulley? No clue, maybe the pulley failed due to the part defect? Aisin makes the OEM part, and it can be purchased (Aisin in Aisin box, not Aisin in the Toyota box) from reputable sources online (avoid scAmazon and fleaBay on purchase to avoid counterfeits)

 

I know you said you followed the diagram. I just recently changed the same parts on my truck. Belt squealed after change. Turns out the belt was routed around one pulley incorrectly. Caused the belt to squeal terribly on startup. After routing correctly it stopped. Maybe check the belt routing again just to be sure. Good luck.