Can you guys splain what the idler pulley sounds like when it's going bad?

08 prerunner with the 2.7 55k miles on it, and about 99% of the time I'm driving, I hear a very annoying chirp at low speeds and at idle,that sounds loudest when I shut off the truck. I have read a few older threads that say the idler pulley is a common cause of this. If it's not the idler pulley, what else? Also, I see what appears to be 2 different idler pulleys on the front of the engine. Which one is the culprit usually?

 

Get a long screwdriver or a stethoscope and listen to each pulley. A useful way to tell if it the belt or pulley is to very carefully take a piece of tire chalk and rub it on the belt with the engine running. If it shuts up it's the belt, if it doesn't you have a bad pulley. Use stethoscope to determine which pulley.

 

I had the same noise. Took off the belt, and spun the pulleys. One was slow. Replaced with oem pulley and never heard the noise again.

Don’t go cheap. Get oem

 

Did yours sort of jingle when you shut the truck off? My mechanic changed the belt a short while ago, but noise was still there. I will try taking it off and spinning them. Thanks

 

No but that annoying chirp. It’s more than likey the pulley. Let us know what happens.

 

One more question. So I took off the belt, and the pulley attached to the tensioner is very slow, could this be the one causing noise? If I understand correctly, I need to buy the whole tensioner assembly because the pulley itself can't be replaced? Is it a bitch to put in?

 

That’s the only one that’s slow?
Idk i never done that one. I just ended up replacing an idler puller because that was the slow one. Check some YouTube videos. Idler was simple. Just take off, put new one and torque it down to specs.

 

Mine made a whine sound almost like a supercharger. It went away when I replaced the 4(?) idlers and belt.

 

Best analogy I can give too..sounds like a supercharger whine.

 

https://www.youtube.com/watch?v=2jN_dGvcxcY

 

You CAN replace just the idler pulley. However, you should look into the whole pulley kit on RockAuto. Just do them all at one time.

 

A lil update and of course another question..
I looked underneath the truck after removing the skid plate and noticed a good amount of calcium which my mechanic friend says is a leaking water pump. So, could the water pump be bad at 55k miles, and if it is bad, would it be causing the chirp, or is the leak a different issue than bearings/ etc?

 

It could be from the water pump weep hole or another coolant leak. But it's most likely the coolant bypass pipe to the heater. It's a plastic pipe behind the intake manifold, bolts on to the the thermostat housing. They are very prone to leaking on a 2.7 2nd gen

If you get replacement parts for your low mileage truck get oem Toyota. You paid extra to get Toyota reliability, if your fine with a Ford ranger then get them from Auto zone.

 

Thank you, I will go check that out right now. I looked a bit last night but couldn't see it.

 

This....
If you hear it, fix it soon. I waited on mine and it ruined 3 pulleys when it went.

Carl

 

Chirping and squealing can be from a lose belt also. If the belt is even slightly loose - it’ll squeak / chirp everytime it slips on the pulley.

If you take the belt off - spin the pulley by ‘hand’. If it feels rough or gritty, then the bearing is bad.
If it spins too easily - there’s probably not enough lubrication left in it. Both situations....need to replace it.

I didn’t have any issues on my 07, but my 96 had a bad lower idler pulley. It would chirp & squeel initially but once the bearing heated up and the lubrication moved around within it - the squealing stopped. That’s just a first sign of a bad bearing.

At the time - I worked as a Machine Operator. I pressed the bearing out of the pulley and replaced the bearing only (with a basic bearing from a local shop). That was a bad idea. The bearing I bought wasn’t rated for that type of rpm’s. All the lubrication oozed out of it within a few days. I ended up buying the entire pulley (with bearing) from Toyota.

 

Noise/sound can vary. Here's a way to help detect which pulley it might be. Someone on this forum posted this a few days ago:

https://www.youtube.com/watch?v=fHtLH_m9gN4

 

So, just to update in case anyone cares, my noise had nothing to do with the belt or a pulley. It was caused by a very kinked breather hose that came with my Volant air intake. My mechanic friend that found it said it was a lack of crankcase ventilation that was causing the noise, and that it was really bad for the engine....

 

Thanks for the update, wish more TW members were like you.