orion4096

iTrader: (1)

I did a 60k timing belt (timing belt+idler+tensioners, balancer belt+tensioner, water pump, plugs - all oem + gates serpentine belt) recently on my (new to me) evo9 and I hear a light, high pitched, constant whirring noise from what sounds like the serpentine belt area. I can only hear the sound in front of the car with the hood open. The car idles and drives fine, but I'm starting to think one of the bearings is going bad in the serpentine idler or auto-tensioner. Although, it's possible the sound was there before and I didn't notice it. Hopefully it's not the water pump - it's brand new and is moving coolant just fine.

Next weekend I plan on pulling the belt off temporarily to see if it goes away. Can I get a shorter belt to bypass some of the accessories to test it? Is it common for the idler or auto tensioner bearings to go bad? Or maybe the sound is normal and it's just echoing off the side of the engine bay? Any ideas on how to figure this out without replacing everything are welcome.

barneyb

At 100K I found the tensioner pulley bearing was a little rough so replaced both. Gates belts have a reputation for making noise.

orion4096

iTrader: (1)

I wonder if the bearings are standard sizes where I can press a new one in instead of buying the whole thing. The tensioner and idler pulley are expensive from the dealer ...

thedru13

iTrader: (24)

My gates belt was rubbing the timing belt cover ever so slightly and made that type of noise. Swapped the belt and noise was gone.

robbyredneck

iTrader: (3)

when i got done building my motor i fired it for the first time and my shortbelt setup chirped pretty good. so i took the serp belt off and ran the car. dead quiet. my idler bearing is pooping out.

meckert

iTrader: (11)

no such thing as a std size bearing. but you can take the bearing number and manufacturer off the existing bearing and go to a bearing supply, and they will get you the rt bearing

barneyb

The tensioner pulley bearing is retained by a flange on the pulley that is rolled over it. I suppose you can maybe grind the flange off. Otherwise you are not getting the bearing out.

I got the tensioner from Advance Auto for $75 which is about half price. It is identical to the OEM part except no maker's name although it is obvious it came from the same plant. Advance Auto had the idler pulley on the shelf (had to order the tensioner) which I thought was surprising since I have the only Evo in town and also few Mitsubishi vehicles of any sort around.

kaj

iTrader: (60)

rockauto.com

thank me later

orion4096

iTrader: (1)

For some reason I didn't think to check the belt. I still have the old one so it's easy enough to throw that on temporarily.

Thanks for the ideas. I'll figure out what it is this weekend and post up.

orion4096

iTrader: (1)

I pulled the serpentine belt and the noise was completely gone. Doesn't look like the gates belt was rubbing anything and a new oem belt didn't fix the problem. Also tried changing the tensioner pulley - no change with that, either. Next up is to change the idler pulley and find someone else with an evo to see if it's normal and I'm just making up a problem that doesn't exist.

kaj

iTrader: (60)

A stethoscope will help you find the issue.

orion4096

iTrader: (1)

I gave a stethoscope a try this morning and I can't hear any crunchy bearings. The PS pump and AC sound the same by the bearing/pulley end and on the other end. The idler pulley sounds fine. Think I'm just hearing normal PS pump noises that I didn't listen for before doing the timing belt swap. I only had the car 3 weeks before the swap was done and never really idled it with the hood open.

kaj

iTrader: (60)

Hm. It shouldn't really be making noise.

orion4096

iTrader: (1)

I agree, but not sure what other options I have. Here's what I've done so far:
- Removed serpentine belt and noise is completely gone. This made me feel better that the timing belt or balancer belt aren't the source.
- Tried a new oem belt in place of the gates belt. No change.
- Threw more money at the problem and replaced both the tensioner and idler pulley/bearing. No change.
- Used a stethoscope to listen to the PS pump, AC, and idler pulley. They all make noise, but nothing sounds obviously bad. The PS pump sounds the same right next to the pulley/bearing and on the other end. Same goes for the AC. The PS pump on my FD rx7 also sounds the same with the stethoscope.
- Played with the rpms. The sound seems to be most noticeable on cold starts at 1000-1200 rpm. Quieter, but still there at 800 rpm. It disappears over 1600 rpm. I can only hear it with the hood up and with my head close to the passenger side of the bay.

It's not a very loud noise to begin with. Shut the hood or step back a few feet from the engine bay and it's gone. It does sound like it's coming from an area closer to the front (PS, AC) rather than back (ALT, WP). I should find another evo in the area and see what it sounds like.

silverevo05

iTrader: (7)

^ so funny I ran into this.

I am having the EXACT same prob. Had a local shop redo everything (24k Miles on car) (had the timing, all bearings and the new IX bracket, Serp belt put in by the dealer) All OEM parts. Then the noise started the next morning. I was told to wera it in.

The shop that redid everything said the timing tensioner was tight (couldnt put the pin in and out) So I thought great the noise will be gone.

After all the work the noise is still there. I especially hear it after the fan turns off (I know they are not related but that is when I hear it most)

I used a stethescope with the shop and I could hear the SCRUBBING noise near the water pump, alternantor and on the the last bolt nearest to the firewall that attaches to the new pulley bracket.

as you, when the serp belt was taken off, I couldnt here the noise so I am pretty glad on that as well.

The three cases similar to mine (youtube videos and members on here, etc) were resolved by a) filling up the PS fluid b) exhaust cam was 1 tooth off or c) it just went away after a while.

If you find out the prob PLEASE let me know. All the Timing and everything else is spot on though. I have a thread on this somewhere on here