Slight chirping noise underhood

[4x4mike]

Recently I've been hearing a very intermittent "chirping" from under the hood. It's at low speeds and usually in a parking lot or pulling into my driveway, at least that's when I hear it. At those times and speeds I'm either downshifting (manual trans), have the clutch pedal depressed or an in neutral coasting. It could be making the noise in other instances but the engine would be too loud to hear it, the noise is that faint.

The noise also comes and goes, like every couple of days. It's not a slipping belt noise and I've checked the belts. They were replaced maybe 50,000 miles ago and look decent but I don't think it's them. I thought maybe it was a clutch bearing in the York or maybe the idler pulley for the York so I cut that belt. It looked like it needed replacing and it's easier to cut it than loosen, monkey around with it and tighten it back up. Turns out it's not the York.

With a little online reading it seems like the timing belt idler might make a chirping noise. Anyone else hear this before? What I saw was just a mention but not a diagnosis issue. Does the water pump also chirp? It's been a day or two since I've heard it so it's hard to track down.

[Seanz0rz]

Could be the ac idler too. Those are known to go south and squeek.

[4x4mike]

If I had to guess the sound is coming from the passenger side more than the driver side. In all I think I'm hearing it after it passes through the grille but that's just what I think. After running a bike and ski shop for almost 9 years I remember hearing a lot of what my question sounded like.

"Well after you ride for at least 7 minutes pushing mostly with your left leg and into a headwind you'll hear a leathery sound. But only then, never any other time."

More to the passenger side would point to the AC idler, good call as I didn't even think of that. I was unaware of their known issues. Ken had mentioned timing idler but that would be more center sounded :P. We had talked about pulling the inspection cover which still sounds like a good idea since I've never had it off. Part of me wants to leave it in place. Kind of like a let a sleeping bear sleep or what you don't know can't hurt you.

Thanks

[paddlenbike]

Belt Noise & chirping
http://www.youtube.com/watch?v=cW_wpE3hG5k

You can try the soap trick too.
http://www.youtube.com/watch?v=dDzVDNdcQiM

After checking the belts, belt alignment, looking for any wobbly pulleys, etc., try the soap trick and if none of that works, I would believe it's probably the timing belt idler.

Is the York perfectly aligned with everything else?

[Seanz0rz]

Especially after those deep water crossings at Mojave. Mine has squeaked for years. I was going to replace it then just got used to it. The older the truck gets, the louder I have to turn the stereo up.

[4x4mike]

It's not a belt chirping. The York isn't in perfect alignment but that's never been a problem. I cut the York belt of Tuesday night and have still heard the noise. My next plan of action is to hit the AC pulley when I have a chance.

After looking it up it appears it makes more noise while the AC compressor is engaged and pumping. Not the case for me.

[slomatt]

Mike,

I had a idler pulley fail on the WRX a couple of months ago and it caused a nice chirping noise, that soon sounded like supercharger whine. When I took the pulley out and spun it it was immediately obvious that the bearing had failed.

You might want to pull off the belt and then spin each pulley by hand to see if they are "crunchy" or show any other sign of failure. If all the accessory idlers look good the next step is to look at the accessories themselves, could be the AC clutch or something like that. Cross your fingers it is not a timing belt tensioner.

- Matt

[4x4mike]

Thanks Matt. Yep it sounds like a super charger for the 2 seconds it chirps. I've been super busy so haven't even been able to pop the hood. I'm hoping it's a pulley though. Maybe I'll try to source the bearing for the AC pulley and just do it since I'll have the belt off.

[4x4mike]

I had just a little time this afternoon so I decided to drop the skid plate and take a look at things. That was my first mistake. About 5 hours later everything was back together but nothing accomplished.

I removed the air box to clean up a mess my OBA filter had made. That led to some more cleaning before I even started on what I was there to do. Finally got to the pulley which is easy to access and easy to remove. Come to find out the bearing in my pulley is not serviceable like it shows on the internet. Instead of a snap ring the bearing has a washer over it then indents that were most likely created by a very heavy press. I cleaned up the pulley and found the bearing is actually super smooth and has no play. I reinstalled it and called it good. It's probably been replaced in a previous life.

Because I cut my OBA belt the other day trying to track down the noise, I am in the market for another. Not having one is like leaving the house without a wallet, it's killing me. I take the cut belt and go to Kragen then Napa to get another. My old belt has all the numbers and size markings but after going through their entire stock we couldn't find one that was the exact size. I chose close then split. Plus it was time, Max had filled his diaper and knocked over a gas can display.

Back at home I ran into an issue I quickly glazed over and forgot about, on purpose. I haven't been bale to remove my fan for something like 4 years. I don't need or want to take it off often but there was once and it didn't budge. I put the bolts back on went on my merry way. Fast forward to today with all my belts loose, 2 pry bars, WD-40 and a spaziming back. I'm not a cussing man...wait yes I am. Especially today. I finally got the fan off and I'm not sure what it's deal was. After about 2 hours or practicing all the French I know, bloody knuckles, loosing bolts, cutting the belt I had just bought, trying to run a die where there is no room for a die and using way more tools than necessary I had completed an exercise in patience and I failed.

In the end everything went back together but I fixed nothing. I might as well been high on acid using popsicle sticks pissing away the afternoon than even start what I started today. I can't replicate the noise, it just kind of comes. The truck is fine and runs but of course doesn't make the noise. Sweet it fixed itself while I f'd up everything else. Oh and I still don't have OBA. If I want it I'll have to find the holy grail belt and then remove the fan and all the belts again.

[Seanz0rz]

Curious why you are removing the fan. I just slip the belts around the blades in the order they need to go. That has always worked well for me.

[4x4mike]

This is the stock setup.
https://lh3.googleusercontent.com/-ieljRbAqrew/UbdKIU_ef9I/AAAAAAAA58E/7WJ4rGOSHDg/s800/DSC06346.jpg

The belt closet the radiator is the PS and the belt on the top pulley going to the right is the alternator. My York belt is on an additional pulley between those to, on the top pulley.

https://lh4.googleusercontent.com/-uz4XNF79F1w/UbdKIr0acFI/AAAAAAAA58M/pQo_BiFxXAo/s800/DSC06347.jpg

https://lh6.googleusercontent.com/-Q-sOfAUgmF8/UbdKILa-m3I/AAAAAAAA574/WJAHMGMvjPk/s800/DSC06345.jpg

It may have been my tired fingers or my lack of patience but with the fan on and the new belt fed over the fan it would not get on the v drive. Whatever was holding it up was in the 6 o'clock position, like the there wasn't enough room between the large upper and lower pulleys. The PS belt has to be removed or taken off the grooves and draped over the shaft. There was just no budging. The fan and the pulleys need to come off and with the 5 hands God gave you, you need to get it all back together all at once.

At that time it had taken me so much time just to get 2 of the 3 fan bolts I could find on, I cut the new belt when I realized it was too short to fit. Something was up with the pulley studs and the nuts wouldn't thread on. Since it was getting late and I was waaayy out of time I didn't risk pulling the fan again.

[slomatt]

Wow Mike, sounds like an epic battle, glad you got everything back together.

[Robinhood4x4]

Have you tried googling the part number of the belt? Usually the internet has everything.

[4x4mike]

I'm really glad the 4Runner doesn't require this belt. Seems a bit spendy.

http://www.amazon.com/500J2-Ametric%C2%AE-Poly-V-Profile-Inches/dp/B00HUZY7HK/ref=pd_sim_sbs_misc_4?tag=ohmy0c-20