Squeal/chirp noise

I've been dealing with a chirping/squealing sound from my engine for a while now and am struggling to diagnose it. It is intermittent, but recently I discovered that I can most consistently replicate it at approximately 1100 RPM while on the gas and intermittently at lower RPMs when not on the gas or on the brake. Also rarely it will remain long enough to do it in park.

Background information:
The truck has 107k miles on it. This noise began after warranty service was completed around 100k. During that time they replaced the timing cover gasket, head gaskets, and water pump. At 105k they also replaced O-rings on the fuel rails, but the noise was not related. The noise happens so intermittently that the dealership has a hard time getting it to go long enough to diagnose and I only discovered the 1100 RPM part after that so I plan to mention that to them.

Things I've looked into:
The belt has no signs of wear. They tried adding belt dressing which did not do anything. He suggested exhaust or heat shield. I found a loose heat shield on the passenger side above the rear cat. The stud came out so I had to JB Weld that. Noise still remains.

It will also happen when not moving sometimes so I don't believe U-joints are a cause.

There are no codes or drivability issues.

My goal here is to have a direction to point the dealership in before my warranty expires at 110k. They've been good with warranty repair so far so I am not concerned that they are trying to dodge that.

Edit: after discovering a way to replicate the noise without moving, the dealership was able to put the truck on the lift and discover the noise was coming from a loose exhaust hanger at the rear of the Y-pipe. They tightened that up and the noise has not returned. Something so simple and yet, so easily overlooked considering the hangers are rubber. Hope this helps someone one day.

 

I would have hoped when they were in there doing all that work they replaced the belt tensioner. Maybe a clutch fan?

 

I don't believe so. In talking to the tech, he did suggest the tensioner, but again, he couldn't get it to last long enough to diagnose it. I thought about the fan too, but it feels normal (from what videos I've seen on the subject). I suppose that doesn't mean that couldn't still be the issue.

Either way, to me, it doesn't explain why I never heard the noise before the work was done. It's possible I simply never noticed it, but I'm usually pretty aware of unusual noises my vehicles make.

 

If you know it does it EVERYTIME you start it or at high idle at 1,100 or something you could drop the belt and start it and idle briefly. If the noise goes away your onto it, but if its intermitent it can be a real pain to find it. Turn the radio up

 

It doesn't do it at high idle or when I start it. It happens when I'm on the throttle around 1100 RPMs (noticable in city driving). Sometimes intermittently below that but I feel like that is mainly an extension of when it started happening when I would have been at that RPM. It doesn't seem to do it if I am slowing down and reach that RPM and most of the time it stops if I let off the throttle as it starts making the noise or if I raise the RPMs beyond approximately 12-1300 RPM.

 

I don’t know if anyone would be willing( or if it works in that way), but perhaps try a dynamometer? Pay for the service to roll at 1100rpm’s and see if you can pinpoint it from above?

 

100 miles on the belt! Change the belt it's not that expensive and easy to do your self and see if that fixes it

 

I had that thought too. It's not out of the realm of possibilities. I just don't understand why it would only start after the service and only seem to be most prevalent at a certain RPM. Belt dressing did nothing, combined with an automatic belt tensioner, makes me think it's something else. But, like I said, it's still possible and I may try that anyway.

 

There are ways to help pinpoint using wireless microphones hooked to different channels. I just have no idea if Toyota uses that method or not.

 

Sometimes during repairs, the engine degreaser, oil, or coolant gets on the belt, the dry belt then never recovers from the change in its nature.

I'd put money on the belt, its why I remove them on easy engines when washing them.

 

X3 try a belt. I like continental. They seem softer, and less likely to squeak IMO.

A theory I have with new components, like a water pump, the pulley alignment can be different. Just a millimeter difference can cause the belt to start squeaking. A new belt can alleviate this by wearing into the new pulley alignment. Just a theory I've heard, and agree with.

 

My truck has been making the same noise for a few years now.
When i start the truck with windows up and radio off i can hear this slight squeal, sometimes it goes away when the idle drops down but it's pretty consistent in the 1100-2000 rpm range.
I've tried lifting the hood to try and listen for it while idling but the engine/fan noise is enough to mask it.
I've just been living with it, i've never had any issues so

 

I'll probably go that route. Can't hurt anyway. I suggested the alignment as well, but the belt looks to be lined up. The tech also said the pulley they pulled off is a direct bolt on system so the alignment shouldn't be an issue (theoretically anyway).

 

That makes sense. It has been 7k miles since first getting it though and nothing has changed.

 

I have noticed a squeal that comes every 30-45 seconds or so when at 2000-2800 rpm and lasts for about 5 seconds. I used to think it was driveline related. But I was able to replicate it when the truck was in neutral (MT) and stopped. Any thoughts what this could be?

 

Been a while since my last update. I went back to the dealership today for my last service before my warranty expires to have this looked at and advise them of the information of how to best replicate it. The tech is convinced it is a passenger side heat shield. Specifically, part number: 1716731110. When my service manager asked him about his confidence in the diagnosis, given that it's more of a squeal sound, he got a bit defensive with her and said it was a heat shield rattle and not a squeal. Either way, the part is covered under warranty and she told me she wouldn't close out the service until I was satisfied that the noise had gone away. Due to part wait times, I'll have to wait until next week before they can install the new one.

Looking under the hood, the heat shield in question appears to be solidly in place and undamaged. It was also hot so I haven't tried wiggling it or anything. It is also not the same shield I mentioned having to JB Weld previously.

 

My service tech is leaning toward heat shield for mine. However, it is possible you could also have a belt issue, especially if you're adjusting throttle at the time of the issue.

 

The dealership replaced the heat shield they suspected and it did not fix the issue. I took a few videos this morning to try and capture the sound. Admittedly, the sound is pretty quiet in the video, but I didn't want to capture wind noise by sticking my phone out of the window.

The video was taken early this morning. There are no external noises that aren't created by my truck so if you think you hear crickets, that is the noise I'm referring to.

 

It’s your HPFP. There’s a TSB and a whole forum about this. I have the same issue on my 2018 OR.

https://www.tacomaworld.com/threads/t-sb-0016-18-chirping-noise-fm-high-press-fuel-pump.542250/

 

I don't believe it is related to the high pressure fuel pump. I could be wrong, but the sound seems to come from below. Although, with the truck on the ground, the noise echoes everywhere so it is difficult to pinpoint, especially when it goes away pretty quickly once the truck is in park.