Whining bearing noise from pulleys

I wonder if you guys could help me out on some whining bearing noise coming from the belts or pulleys. This is on a 1999 Pre-Runner 3.4 L. with 240,000 miles. I can't tell if it's an alternator, power steering pump, idler pulley or A/C. Is there any easy way to isolate one of these items? When I turn the wheel back and forth it doesn't get any louder on the power steering pump(it's full of fluid). I thought I could just buy an idler pulley and take that off with the corresponding belt, crank it up and see if that eliminates the sound. Then go from there. Any suggestions? Thanks for any replies!

 

use a stethoscope, if you don't have one a piece of wooden closet pole or wooden dowel will transmit sound very well. try and place either of these as close to the suspected noise maker as possible and listen for the squeal. You can also remove each belt one at a time and start the truck, just don't run it for more than few seconds. This method will help eliminate what is making the noise.

 

Easiest and quickest way is to get a spray bottle with just water in it. With the car running, spray one belt at a time. If the noise goes away then you know it is the belt you just sprayed.

 

You don't need to remove the belt to change the idler pulley. Just loosen the adjuster, you can then dismount the pulley. The bearing in the OEM idler pulley is swap-able so it's worth saving that pulley.

 

Thanks to all who replied, I will try the spray bottle tomorrow. While driving around today I turned the A/C on and off> it made no change in the sound. My wife works at a doctors office so I will see if she can bring a stethoscope home and I will try that next. It's not a whining/screeching sound kinda of a low groaning sound. Mr. Digiratus thanks for that info,I didn't know you could just change the bearing in that pulley. Do you have to go to Toyota to get that bearing or somewhere else. I put all new belts, hoses, water pump, timing belt and tensioner on it at 212,000. All were Toyota parts.Thanks to all, Dave

 

This is the what I use.

$16 PGN (10 Pack) 6301-2RS Bearing - Lubricated Chrome Steel Sealed Ball Bearing - 12x37x12mm Bearings with Rubber Seal & High RPM Support

https://www.amazon.com/dp/B07BY6Q45L

It is a little cheaper to purches a 2-pack instead of a 10-pack, but not a whole lot less. Either way, cheaper than buying an OEM replacement and will last just as long.

$8 PGN (2 Pack) 6301-2RS Bearing - Lubricated Chrome Steel Sealed Ball Bearing - 12x37x12mm Bearings with Rubber Seal & High RPM Support

https://www.amazon.com/dp/B07BYFF42...9bb1c55e1182&s=industrial&smid=A3RMJZMAP3U4RK

 

Another thought, it could be your fan support bracket. I would try the A/C idler bearing first since getting to the FSB takes little time but I would suspect that if the A/C bearing doesn't eliminate the noise.
https://www.tacomaworld.com/threads/fan-carrier-bracket-advice.365007/#post-9937548

 

OP,
I normally 4 wheel in deep mud/high water which kills that low hanging idler pulley bearing quick! That is usually the source of any squealing noise on my '97 V6 Taco. Have probably changed it a dozen or more times in 25 years. The OEM bearing in the idler pulley is usually a JAPAN NGK or JAPAN Nachi which you can get off Ebay for $9 shipped: 6301-2NSE9 NACHI bearing 6301-2NSE seals 6301-2RS bearings 6301 RS Japan | eBay. It's a cheap and easy fix. Good luck!

EDIT: The type bearing is a 6301-2RS which has seals on both sides. But the different companies have their own nomenclature for that type bearing. The JAPAN bearings last longer for me. I think I am currently running an NGK JAPAN bearing.

 

I have not replaced the lower idler pulley ever. I have changed the timing belt, the water pump, all the belts and hoses, cam bearing but I guess I overlooked that lower idler pulley. Toyota's are fantastic for the durability of the parts. I don't know how many people have tried to buy mine over the years, but I will never sell it.
Thank all of you for the assistance!!! I am working on it now and I will post what I find. Thanks for the ordering info as well. I love Tacoma World as it has a lot of great guys on here. I have been a member since 2014. Thanks so much for the help, David

 

Second this method, I use a long flat screwdriver, and put my ear to the end with the engine running, just be careful not to have loose clothing and a long beard.

 

Thanks to all you guys. I did order a stethoscope and listen to all the suspect items. Man it was a lot louder than I thought it was going to be with the stethoscope. Anyway I think it is the alternator bearings, so I am ordering those and the lower idler pulley too. The truck has 242,000 miles so I don't mind changing a few things. I will post what happens when I change each one of those items. Thanks so much,Dave

 

Good luck man, looking forward to your updates!

 

Same here ^, I have 232,000 and wondering if I should replace my alternator bearings given the mileage. Original alternator as far as I know.

 

Thanks for the update. I strongly suggest you consider replacing the alternator brushes while you have it out of the truck.

 

This would help isolate a squealing belt, but would not help isolate a whining bearing, as described in the OP.

 

My Toyota brothers, I changed the idler pulley bearing yesterday, going to test it tomorrow. I think it may be that as I cranked it up after installation and I don't think I hear the whining. I will let y'all know after I drive it. I did order the alternator parts(bearing's), and to Andy, I did order the brushes too. I'm sure many of you know about Amayama for Toyota parts. It's pretty crazy that you can order genuine Toyota parts from Japan or United Arab Emirates cheaper than anywhere in the USA. When I rebuilt my front end I saved about $500 on all the parts buying from that place. It didn't take that long(7 days) to get the parts and they were genuine Toyo parts.

Anyway for everyone's help> I ordered some extra idler bearing and for the first 3 people that reply and need or want one of these,I will send you a free one, sort of a pay it forward freebe. I guess you would have to pm me on here with name and address. The part was a 6301-2RS bearing, I will pay the shipping.(which is more than the part). If anybody wants one, let me know.

 

I was looking at their website after reading your post, and they don't list the 1st Gen Tacoma for parts. Did you order these from the 4 runner option.

 

I used my Vin number when I order from them>

 

thanks for the reply, I'll try that and see what parts show up.

 

I would love to get a bearing since I'm going to be rebuilding my alternator very soon (225,000 miles). I will send you PM with my name and address. I can paypal or venmo you the shipping. Also thank you for the info on the website, will look into before I order next set of parts.