2001 4Runner Engine Noise - Bearings or Pump?

[bbuoni8]

Hi everyone,

I am a first time user on this site. I have a 2001 SR5 Sport RWD with 158K on it. In Central Ohio, we just had our first below zero weather, and am getting a strange sound that fluctuates between sounding like an old time fax machine, and the sound I have attached -- I have attached a link to the Youtube audio I recorded today. This is the 3rd time it has happened in 3 days. Each of the 3 accessory belts are either near new or new, and the A/C idler pulley was replaced in the Spring, along with the A/C accessory belt. A few other items I have noticed -- the truck has a brief chirp on wet mornings, or when it is raining, when you first start up. Also, it is starting to almost sound like a turbo when accelerating. I am clueless. Any ideas or help would be appreciated.

https://www.youtube.com/watch?v=tY6daEnMm5k&feature=youtube_gdata

 

[sterbenlicht]

Hi everyone,

I am a first time user on this site. I have a 2001 SR5 Sport RWD with 158K on it. In Central Ohio, we just had our first below zero weather, and am getting a strange sound that fluctuates between sounding like an old time fax machine, and the sound I have attached -- I have attached a link to the Youtube audio I recorded today. This is the 3rd time it has happened in 3 days. Each of the 3 accessory belts are either near new or new, and the A/C idler pulley was replaced in the Spring, along with the A/C accessory belt. A few other items I have noticed -- the truck has a brief chirp on wet mornings, or when it is raining, when you first start up. Also, it is starting to almost sound like a turbo when accelerating. I am clueless. Any ideas or help would be appreciated.

https://www.youtube.com/watch?v=tY6daEnMm5k&feature=youtube_gdata

It's difficult to tell exactly what's happening even after listening to that, but check the belts. Sometimes after replacing them, they'll sort of wear in a bit and be a little loose. Make sure there's some tension on them, and tightening them will maybe get rid of the chirp. Also make sure none of them are too tight. If you can't hardly twist it at all, then it's probably a little tight, and it'll cause problems for bearings and noises in P/S pumps and such. If all that checks out, and judging from your description, it might just be a tired P/S pump which isn't uncommon. When the fluid is really cold, it'll sing, but when it warms up it may get a little quieter. After time it'll get worse so that it'll whine most of the time, and I'd try to change the pump before it gets that bad.

 

[nissanh]

Did you start to hear it in the cold weather?
Wold it disappear after engine reaching the operating temperature?
I feel the AC idler pulley is making the noise. Did you got a good branded pulley?
Any information about the timing belt/water pump?


Let us know.
Thanks

 

[bbuoni8]

Hey guys,

Thank you for the response. All the belts seem to check out OK... they are all between 9 months and a year old, with less than 15K mile on them. A few other details. I replaced the A/C idler pulley with a GATES pulley and Gates belt in the Spring, because I was getting a "whirring" sound during humid or wet weather. This fixed the whirring sound, but I still get some quick belt chirp during wet weather on cold startup only. The water pump and timing belt were down 30K miles ago, in May 2012. I installed as part of a kit -- believe it was Mitsobushi.

A few other details:

1. This most recent sound started when the weather got extremely cold, and changes with the RPM of the motor only. It happened on a warm engine at first, and then happened again when the engine was cold. It first lasted for over 20 minutes, and then again for several minutes

2. The sound has changed.. At first it sounded like one of the old fax machines that would ping, followed by static, and then it moved to the whirring sound on the Youtube link. This sound is almost identical to the chirping sound in the following link, between seconds 3 and 10 (not the groaning sound... the higher pitched sound)

https://www.youtube.com/watch?v=NbFek8n5Mac

3. The sound has not happened today, and the temperature is in the mid 20s.

4. On cold mornings, for the past several months, my rig sounds like a turbo - it sort of whistles as RPM's go up and down. This does not go away, but does get a little quieter as the engine warms up. I thought it was a vacuum leak at first, but have not been able to locate any leaks at all.

Any thoughts guys? I am stymied... wondering about the power steering pump, but fluid looks good, and is full... Any thoughts would be most appreciated!

Bryan

 

[bbuoni8]

Am thinking that it could be the power steering pump or Air Conditioning Compressor. Is there a way that I can discern which it would be w/o removing belts? Thanks.

 

[Riceye]

It really sounds like your A/C belt idler pulley bearing is at fault, here.

To service or replace, you need to crawl under the front near the drive belts and release the tension of the A/C compressor on the belt. The idler pulley is situated right next to the A/C compressor. Next, remove the pulley and inspect it by spinning. If it is tight or growly, you can just replace it. Or, if you are a cheap bastard as I am, pop out the seal on the sealed bearing, clean the rollers with an aerosol parts cleaner, re-grease and reinstall the seal. Bolt the pulley back to the engine, reinstall and tension the belt, and you're done.

It's a half hour job.

 

[bbuoni8]

OK guys... it ended up being the alternator going south... used a long screwdriver and listened to a/c compressor, power steering pump, and then alternator. Hands down it is the alternator. Going to order the new part tonight.