Diagnosing Chirp on Warm Up w/o Accesory Belt (1 Viewer)

[urist]

Gents,

Trying to diagnose a squeak from the front of the motor that sounds like a pulley or belt, but still occurs when the accessory belt is removed. Details:

1. Does not happen immediately on start.
2. Usually takes 1-2 minutes before the sound starts.
3. For me today, the sound started when the coolant was at 55 degrees C.
4. The sound stops once the motor reaches operating temp. When the motor idles down since it has enough heat in it, the sound goes away immediately.
5. The sound does not return once it's gone. Throttle doesn't bring it back. It will only return on another cold start.
6. The colder the start, the louder the noise.
7. It occurs with the accessory belt off.

What I've done:

1. I've put a new OEM Toyota accessory belt and idler pulley on it, but no fix since this happens with the belt off. The tensioner could stand to be replaced but not the core issue here.
2. I've followed most of the advice of @2001LC and @mike-nxp in this thread: Help identifying engine sound - https://forum.ih8mud.com/threads/help-identifying-engine-sound.1307818/ . But I could draw no conclusions.
3. I listened with a stethoscope in as many places as I could and couldn't find it.

I've taken several videos showing the sound or lack of sound. Unfortunately my phone crapped out when recording the critical videos, so you can only hear the sound shortly, but it's definitely audible. I will record a new video of the squeak ASAP once its cooled down again.

And yes, the truck's filthy. I washed the recent salt off it after recording these.

Cold start after several nights near 0 degrees F. No squeak on start.​

Cold crank w/ accesory belt removed. No squeak on start.

Checking out the pulleys, though not as important since it still occurs w/ accessory belt removed.​

Pulley Check - Embed

Watch this embedded Streamable video.

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Squeak Starts @ 55 degree C coolant​

Unfortunately my phone begins failing to record video. Sound is lightly present here from the bottom side.

Squeak Starts w/ Coolant @ 55 C (No Belt) - Embed

Watch this embedded Streamable video.

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Squeak heard from topside at middling temperature​

Again my phone failed on me, but you can certainly hear it here.

Squeak from Topside (No Belt) - Embed

Watch this embedded Streamable video.

streamable.com

So...am I looking at timing belt problems? I had it done in the last year. Why does it go away immediately once the motor's at operating temp?

Thanks for any help.

 

[urist]

Gave it another go this evening about 6 hours after last driving it. Coolant started at 30 degrees C and worked up to 75 before I gave up after 10 minutes, and no squeak the whole time. I reckon the block needs to be fully chilled through as well as the coolant, which may be another clue. I'll do it again in the morning and get a proper recording then.

A friend smarter than me wondered if its a metal-on-metal contact in a pressurized path that begins cold and with a small gap that used to be sealed, but as the block heats up and expands, the gap seals. Reasonable guess but doesn't explain why there is no squeak for the first couple minutes after starting the motor -- if there's a gap, surely it would make sound at startup unless that air path isn't flowing initially after startup.

 

[rexington14]

Need better video.

Check if the noise is coming from the throttle body. If so, clean the throttle body, and the MAF.

 

[urist]

Need better video.

The truck painted me a fool this morning and did not repeat the issue. It's done it on every cold start for the last 2 months. It was about 34F outside, not as cold as it has been.

I looked through my phone and found an old video of it doing it. Unfortunately I'm talking during the video and making notes to myself but you can hear the noise in this one. As soon as I can get it to chirp again, I'll get a vid with only the chirp sound and post here.

Will check throttle body.

 

[urist]

@rexington14 I cleaned the throttle body. It was in need. Here's some pics.

Before. I didn't get a pic behind it, but there was significant carbon buildup.

After, looking a good bit better.

But, this did not fix the issue. Though I may have recovered a horse or two from the motor, based on driving MPG this week.

What I did get was much better videos of the issue. Here's a video while running of the chirp:



And here is a video of a startup and shutdown. You can hear the chirp continues slightly after the motor dies. My next guess now is the fan clutch.



My next guess now is the fan clutch. I have one on order now. Any other ideas, considering this still happens with the accessory belt off? I figure beyond the fan clutch, I'm in water pump territory.

 

[rexington14]

If the noise is still there when the serpentine belt is removed then that rules out the fan clutch since that won't be spinning. Not a bad idea to replace it anyways though if it's original. And clean the MAF (easy job).

Did you use original Toyota or Aisin parts for the timing belt water pump job? Chirp could be there.

 

[2001LC]

Not uncommon for pulley bearings to chirp while cold, then quiet down once warm.

I see a Toyota Timing belt sticker. Dealership T-belt service, rarely change the t-belt idler & tensioner pulleys. Much less fan bracket, fan clutch & tension assy or drive belt.

Check your work order, from T-belt service. See what parts listed. If no,T-belts pulleys listed. Likely the chirp.

 

[ChiefKeef]

So I've been dealing with squeak/squeal/chirps for probably 3 years. I've actually narrowed it down (for me) to relative humidity. I rarely, if ever, get noises in the spring/summer with the humidity of the ambient air is higher. In the winter, when the humidity is lower, I will get random days that I chirp and squeal like a banshee. Sometimes its on start up and goes away, other times she squeals all day long. I've checked/replaced everything up front and it still comes and goes randomly. It's never affected performance, it just sounds like i'm driving a 20 year old $hitbox. I know this is less than helpful, just saying I feel your pain lol

 

[2001LC]

So I've been dealing with squeak/squeal/chirps for probably 3 years. I've actually narrowed it down (for me) to relative humidity. I rarely, if ever, get noises in the spring/summer with the humidity of the ambient air is higher. In the winter, when the humidity is lower, I will get random days that I chirp and squeal

banshee.

Often a bad serp belt. But can be pulley bearing or combo.

Sometimes its on start up and goes away, other times she squeals all day long.

Bad sign.

I've checked/replaced everything up front and it still comes and goes randomly.

You should list "everything" .

It's never affected performance, it just sounds like i'm driving a 20 year old $hitbox.

Bads pulley bearings or belt don't. Until the belt goes.

I know this is less than helpful, just saying I feel your pain lol

 

[urist]

Not uncommon for pulley bearings to chirp while cold, then quiet down once warm.

I see a Toyota Timing belt sticker. Dealership T-belt service, rarely change the t-belt idler & tensioner pulleys. Much less fan bracket, fan clutch & tension assy or drive belt.

Check your work order, from T-belt service. See what parts listed. If no,T-belts pulleys listed. Likely the chirp.

Thank you, always a big help. The last Tbelt service was done with OEM parts, but was done third party and doubt that they did the T belt pulleys, as you mentioned.

I did the fan clutch yesterday evening. Unsurprisingly, since the chirp occurs with or without the accessory belt, the chirp is still there. But, the fan is performing quite well. : ) Here is probably the best video of the sound that I've gotten. Taken today at about 60F ambient temp. You're probably right that it's my timing belt pulleys, but I wish you weren't. Let me know if this sounds like anything else.



And question for you, @2001LC: I assume there's no good way to diagnose Tbelt pulleys without taking the covers off. Especially since I can't hear anything with a stethoscope on the covers. The motor can't be started without the Tbelt covers on, since you have to take the thermostat and coolant return line off, right?

 

[2001LC]

Thank you, always a big help. The last Tbelt service was done with OEM parts, but was done third party and doubt that they did the T belt pulleys, as you mentioned.

I did the fan clutch yesterday evening. Unsurprisingly, since the chirp occurs with or without the accessory belt, the chirp is still there. But, the fan is performing quite well. : ) Here is probably the best video of the sound that I've gotten. Taken today at about 60F ambient temp. You're probably right that it's my timing belt pulleys, but I wish you weren't. Let me know if this sounds like anything else.



And question for you, @2001LC: I assume there's no good way to diagnose Tbelt pulleys without taking the covers off. Especially since I can't hear anything with a stethoscope on the covers. The motor can't be started without the Tbelt covers on, since you have to take the thermostat and coolant return line off, right?

Short of it: Remove the Timing belt.
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I suppose one could "rig" to start, for a few moment without covers or coolant. But I would not, since water pump would be running dry. It would also take to long to "rig". Faster to just pull the T-belt. Then spin its pulleys and WP.

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If you don't have parts list, you can contact shop that did the T-belt service. But even if shop replaced with OEM, they can go bad.

I assume good oil & oil pressure, coolant is to top of radiator and engine coolant temp is running in normal range (ECT 184 to 187F).

Since same chirp, with or without serp belt on. It's 97% change a T-belt pulley is chirp, 2% chance water pump, 1% other.

Try listening, from oil pump housing:
If you listen with stethoscope, on oil pump housing. It may yield, chirp pass through sounds from pulley bearing. Since both pulleys are secured to it.
Picture to help, know where to place stethoscope prob. With all covers still on, engine running.

In the end these are all just clues.

Bottom line:. You'll need to remove timing belt. Then spin pulleys and water pump by hand. It's not likely water pump, but check


If they didn't replace TB pulleys. It is not likely they replaced fan bracket (FB) or serp belt tensioner. If either even questionable, replace them.
Here's a fan bracket at 18 years and 24K miles. FSM states: any oil coming from seal of FB, replace FB.

Others at various mileage and ages

This FB seal, was wiped clean. Look close and you can still see the oil shean.

If tensioner pulley makes any sound, or just free spins and keeps spinning. Replace the serp belt tensioner.

 

[rexington14]

Maybe another clue if TB pulleys were recently replaced is to look at the Timing belt tensioner shaft that extends downward between the alternator and the front crank. Does the finish on it look new(er) or old?

 

[urist]

@2001LC

Try listening, from oil pump housing:

Thank you for that explanation, I didn't know enough about the TBelt change to know that those are connected. I will try this.

Bottom line:. You'll need to remove timing belt. Then spin pulleys and water pump by hand. It's not likely water pump, but check

Its unfortunate -- the TBelt was done less than 15k miles ago. But better to do it right. I assume if I'm going to all the labor to get in there, I might as well replace the TBelt with a new one? If I don't have to for a low mileage TBelt, is it possible to de-tension the belt tensioner and remove the tensioner pulley and idler pulley while the TBelt is still attached and properly aligned? Then I can just swap them in. I assume there's a gotcha in the assembly that won't allow me to do this.

 

[urist]

Maybe another clue if TB pulleys were recently replaced is to look at the Timing belt tensioner shaft that extends downward between the alternator and the front crank. Does the finish on it look new(er) or old?

I will check. Thank you.

 

[2001LC]

@2001LC

Thank you for that explanation, I didn't know enough about the TBelt change to know that those are connected. I will try this.


Its unfortunate -- the TBelt was done less than 15k miles ago. But better to do it right. I assume if I'm going to all the labor to get in there,

I might as well replace the TBelt with a new one?

If getting, the Aisin TKT-021 kit. It, has all (belt, pulleys, water pump, both O-rings and tensioner), so may as well. If happy with water pump, that's there. You'll not need water pump or O-rings, or to remove water inlet.

If I don't have to for a low mileage TBelt, is it possible to de-tension the belt tensioner and remove the tensioner pulley and idler pulley while the TBelt is still attached and properly aligned? Then I can just swap them in.

Yes, if belt good. Toyota or Mitsuboshi are good belts. Gates are junk. Oil on belt, don't use.

1. Set crankshaft zero line on the lower T-cover's little peg. Camshafts timing marks on the "T"s. This position, camshafts will hold still.
2. Place small clamp lightly holding belt on each pulley and crankshaft sprocket. This is so belt, can not change tooth position.
3. Remove the two 12mm bolts, to pull off tensioner. You'll need to compression a stake, later to reinstall. 19ft-lbf.
4. Then remove 10mm allen head bolt, from tensioner pulley (idler #1, RH pulley). 25ft-lbf. Very important: Use a sealant on it's threads
5. Then remover idler pulley (idler #2, LH pulley) 14mm bolt and remove pulley. 25ft-lbf

Notes:

• RH side is your right, as when you're sitting in driver's' seat.
• With the belt in place. This will make aligning of pulley bolt difficult. Replace all bolts by hand, all the was in (do not use any wrench). This way, you can not cross thread, damaging oil pump or other components. Use torque wrench, to secure all bolts to spec, once they are in all the way and sung.
• If pulleys, not replace during last T-belt service. Likely fan bracket and tension not either. Consider those if any doubt as to condition.

I assume there's a gotcha in the assembly that won't allow me to do this.

I do T-belt service differently, then most anyone:
I replace every parts even questable. Most get new fan bracket and many serp belt tensioner.
I put a 1282B bandaid on block filling pits, behind water pump gasket.
I install T-belt, before pulleys. To this end, run bolts in by hand. Insuring, I can't cross aluminum thread in oil pump.
I use a torque wrench, for all bolts.
I paint ever bolt after torquing

Yesturday, 4.7L 2UZ-fe VVTi. at 197K miles, 80K since last T-belt service. I found water pump, tensioner and both pulleys, Appeared to be the factory installed ones. Very common when I see a Toyota T-belt sticker. Tensioner (1# idler, RH) pulley was failing. Idler (#2, LH) pulley, okay but certainly not reusable. No oil leak at tensioner 10mm allen head bolt or crankshaft seal. Factory installs, never do leak.

I clean even the grooves of all pulleys, even the serp belt if being reused.