Noise at Cold Start - Idler Pulley? (1 Viewer)

[taylort232]

Any ideas? I am suspecting idler pulley, and have ordered new ones and new belts. But it's a weird noise.

It is only at cold start - and it goes away within around 15-20 seconds after start.

 

[taylort232]

This might be a better video. It almost sounds like a really low almost metally rattle that comes and goes, and eventually turns into a squeak. It goes away at 1:13 and doesn't come back until I turn off and back on (with some time to cool)

 

[Fj80oregon]

Take the idler pulley off and see if it still persist.

 

[LongDuck]

Also, Toyota belt kits are sold with 2 belts sliced from the roll next to one another making them much more consistent for diameter under load. Two random belts - or even 2 Toyota belts from different lots - will stretch differently, and one will be smaller than the other resulting in some skipping and harmonic vibration.

My guess is that once the engine spins a bit, the smaller belt heats up and expands a bit, evening out the noise.

 

[mudgudgeon]

Video sucks, sorry! Can't hear it.

I agree, remove the Idler and see if it stops.
The Idler isn't actually an Idler pulley, so you can run without it.

The other common things that can make a metalic squeak/ rattle with the belts is the AC belt tension adjustment pulley.
Or, the AC compressor front bearing.
Remove the AC drive belt and see if this stops the noise.
If it's the tensioner, rotate it by hand to see if it squeaks or rolls freely.
if not the tensioner, check the AC bearing. Thia bearing can be swapped with the AC pump still in place, so no re-gas required. Actually a fairly simple job.

 

[taylort232]

Great info thanks

Will report

 

[taylort232]

How long can I run it without the idler pulley on?

 

[mudgudgeon]

How long can I run it without the idler pulley on?

The idler near the alternator doesn't actually touch the belts when the engine is not running.
Some people leave it off permanently, but toyota had reason to put it there

 

[Broski]

The idler near the alternator doesn't actually touch the belts when the engine is not running.
Some people leave it off permanently, but toyota had reason to put it there

^^^^ this

 

[flintknapper]

How long can I run it without the idler pulley on?

Forever if you like.

It's not an 'Idler' in the true sense of idler pulleys. More of a 'damper' to attenuate the 'slight' amount of belt deflection present over a fairly long run of belt (unsupported). Many folks dispense with it altogether with no ill effects.

Yes, Toyota put it there for a reason (overkill and extra assurance). Same reason they put TWO belts on it (redundancy and reliability under harsh conditions and use).

 

[taylort232]

I pulled the idler pulley - no effect.

I did run it a bit tonight, and whatever it is bogs to the point that there is visible voltage drop and the headlights dim. Is this consistent with something sticking on the belt and causing the alternator to spin slower? Or am I wrong about that?

 

[flintknapper]

I pulled the idler pulley - no effect.

I did run it a bit tonight, and whatever it is bogs to the point that there is visible voltage drop and the headlights dim. Is this consistent with something sticking on the belt and causing the alternator to spin slower? Or am I wrong about that?

Might be easiest to just remove the belts and hand spin everything. Any 'rough' bearings or items trying to seize should be apparent.

 

[taylort232]

I pulled the belt on the compressor side. Compressor and adjustment pulley spun fine. I can't tell though if the adjustment pulley might have too much lateral play from being worn out. New one will tell.

I guess all that leaves is the water pump or the alternator, right? I will investigate those tomorrow.

Is there any way its the actual crankshaft binding up?

 

[taylort232]

Ran it with the AC off and the noise went away. It's the compressor clutch. Ordered a new one.

 

[mudgudgeon]

Ran it with the AC off and the noise went away. It's the compressor clutch. Ordered a new one.

May not be the clutch. The bearing in the nose of the compressor are known to go bad.
They'll make a racket.

Easily changed while you are dealing with the clutch

 

[taylort232]

The compressor is about a year old new denso. The noise only shows up when the clutch is engaged.

I hope it’s the clutch! Any idea on part number for the bearing? I didn’t see it on the diagram

 

[mdawg]

I can’t tell from the video, but check out the thread below and see if this matches your observations:

Engine rattle investigation

So I have had a rattle that used to go a way after a few minutes. Then it got to the point that it was getting louder and not going away. Previous recordings made it hard to hear it over the sewing machine sounds but finally got a good recording. Could never hear it with a engine stethoscope...

forum.ih8mud.com

 

[taylort232]

I can’t tell from the video, but check out the thread below and see if this matches your observations:

Engine rattle investigation

So I have had a rattle that used to go a way after a few minutes. Then it got to the point that it was getting louder and not going away. Previous recordings made it hard to hear it over the sewing machine sounds but finally got a good recording. Could never hear it with a engine stethoscope...

forum.ih8mud.com

Thanks for the link. I don't think this is related - but something to remember. I think my oil pump is original from 97.

 

[Trollhole]

The compressor is about a year old new denso. The noise only shows up when the clutch is engaged.

I hope it’s the clutch! Any idea on part number for the bearing? I didn’t see it on the diagram

If you have an iphone put a white mark on the belts and across the front of the pully on one side. Could do the same on all the pulleys. Then put phone in slow mode video and start the vehicle. Then go back and review the video. Helps a lot in figuring out issues. It almost sounds like a bearing. Possibly in alternator. Could be crank pulley has separated.

 

[taylort232]

Are you saying a straight white line across the two belts and pulley? Like one stroke?