My 98 4Runner 3.4 has a noise that seems to be from the front of the engine. It sounds like an idler bearing failing and it only occurs at operating temperature. I can't stand to go through a drive thru anymore. At temperature, the noise is present. I removed all three drive belts and the noise is still there. So, I ordered new idler pulleys, upper and lower. I installed these yesterday. Now I'm just $160.00 in the hole with a noisy engine. I have recently replaced the timing belt and water pump, so going back in to replace the idlers really sucked. It doesn't really sound internal, but it's obviously not external. My only thought at this point is maybe the oil pump. Anyone elese have a similar issue or have any idea? I know noise help is hard to get online, but I'm hoping I have described someone elses issue. Thanks in advance.

 

use a mechanics stethoscope to pinpoint the location

 

i edited your thread title from "this noise is driving me crazy" in the future please make sure your thread titles are relevant per the rules....the thread could have been deleted.

 

Well, me and one of the mechanics at work used a stethoscope the other day to pinpoint this issue. We were pretty certain my water pump was the cause. I replaced the water pump today and I still have noise. If anyone has heard a bearing failing in an idler, this is the noise I am hearing. This truck has almost 200k miles on it, I guess I really just need to quit being so picky.

Sorry ocdropzone and thank you.

 

ya mine had a awful noise turned out to be the water pump going out but since you have replaced everything im out of idea's

 

tb idlers

 

Maybe take a sound clip and post up here? Mine was making a terribl enoise, and it turned out to be the AC compressor idler pulley.

 

Here is a video I shot from under the vehicle. Underneath is the only place I could catch the sound good without fan noise. The metallic noise you hear is my problem, the rest is fan noise. This noise is present with no belts on any pulleys. The water pump and idlers HAVE been replaced. Anyone who has heard this before and can give me a clue as to what this is, please educate me.
FORGOT TO MENTION IT ONLY MAKES THIS NOISE WHEN AT OPERATING TEMPERATURE
http://www.youtube.com/watch?v=GALhTfZY8hU

 

No idea. Start eliminating culprates. As in unhook, and remove one accessory belt at a time, then run, and see if you have the noise. Run for a short period, because you don't want to mess anything up.

 

That's just it, the noise is present with nothing but the crank pulley spinning. I have had all acessories and timing covers removed with the engine running. When it warms up, the noise starts appearing. It's quiet as can be when cold.

 

timing belt idlers it sounds like to me. my wifes 97 4runner did the same thing till i replaced them.

 

Already replaced them.

 

Bump... I have this same problem

 

You could have had a bad part you know.

 

inspect the flex plate for cracks. Remove the drive belts to eliminate p/s, a/c and fan bracket bearing issues. If that fails to eliminate the noise then you'll need to start digging into the motor.