Timing Chain Possibly Getting Ready to Grenade?

What about Gates?

 

Personally, I like the gatorback. JMO. True mix between Gates and stock (Dayco). You get the cross grip of the Gates, but the same groove lines of the stock belts so they ride on the pulleys consistently.

 

To me, it sounds like something turning a lot faster than the engine. Small pulley. Alternator bearings?

 

I'm right in the middle of my work week, assigned to the 7p-7a shift, so I didnt get a chance to do any work on it today. I did grab a stethoscope the other day, and I poked around while the truck was making the noise, it's hard because I only have like a 3-5 min window before it stops. It sounds like it is actually the idler pulley that is right on the top, driver's side of the front of the motor. I touched the scope to the bolt holding that pulley on, and it was loud, but it's not moving back and forth or anything - probably because the belt is holding it tight. It seems straight forward to replace, I'm just not sure if the bolt is backwards threaded. ...and of course a socket doesnt fit between that bolt and the fan, so i have to pick up a wrench that will fit it in the AM and try to get it off. For now, I hosed it down with deep creep and belt dressing, not sure if itll make a temporary difference until I can get another pulley or not.

I'm still not sure I'm convinced that is what it is, but the scope definitely didnt make noise when i had it on the valve covers, so safe to say it's probably not timing chain related.

 

Let the betting begins!

I Bet it’s The

TENSIONER!!!!!

 

hahaha Could it be the idler though?

 

Sure.

 

Fucking truck and it's witchcraft.

 

I think carburetors are witchcraft...

 

Agreed 10000000%

 

Well, spent 2 hours in the rain in my driveway replacing the tensioner this morning... Sorry to report that did not fix the issue. Kind of losing my patience. Replacing that idler looks like a huge pain in the ass and who knows if that's the problem. I don't want to bring it to the dealer not knowing what the issue is at 100/hr for them to say it's nothing to do with the drivetrain... Fuck

 

Did you spin each pulley by hand?

https://youtu.be/sWKq552xYwM

 

Damn bro...I know it sucks chasing an issue. Like I said earlier, when chasing an issue like this, start with the cheapest and work up. I know my local dealership will let me bring in parts (not sure if it's limited to only OEM or not) and just pay them the labor....just an option maybe. I prefer doing my own maintenance (outside of a warranty), but sometimes it comes down to your time and sanity.
Maybe @LOTSOFTOYS could help. Have you looked at the thread he comments on, the Ask a Toyota Mechanic thread?
https://www.tundras.com/threads/ask-the-toyota-mechanic.2404/page-36

 

You asked if it could be the idler, answers were in the affirmative. You went after the tensioner. Removing the tensioner necessitates removing the belt, as does replacing the idler. You missed two birds with that one stone.

 

I did while I had the belt loose (tensioner locked in). None of them had play - the idler has quite a bit of sound through the stethoscope when the truck is running and I have the scop touched to the bolt holding it on. Sounds exactly like that video through the scope, but has no play. Just wondering if that would create a knocking noise, and if a noise caused by an idler pulley would go away after it warmed up?

Yeah, there is a garage in town that is owned by a family friend, really good guy and treats me well. When I need something fixed that isnt covered by the dealer, I take it to him. I am somewhat mechanically inclined, I just dont have a ton of tools, so I like to do what I can before I have to go a few days without my truck... I posted in LOTSOFTOYS thread, I know he's a busy guy, so just waiting to see what he says.

Yeah, I was thinking more and more about the idler, I stopped at every auto parts store on my way from work at 7a that were between my house and work. None of them had an idler pulley for the truck, so that's honestly the only reason I didn't replace it. I didnt even remove the belt to replace the tensioner, it was a relatively easy job - I don't think I'd have to pull the belt for that idler now that I think of it either. There should be enough room to pull it off with the tension just off the belt. The biggest pain in the ass thing about any of this, is putting the fucking skid plate back on when youre done!!!! Huge C***.

 

I'm with Daddy on this one.

But I will say this. Toyotas for whatever reason make this noise when it comes to pulleys. I had this exact issue with my Tacoma and my 4runner. Both of them used off road a lot. And muddy water or debris getting in the pulley will make it sound squeeky, knocking- or it will whine like a a cheap wind up toy.

The tensioner will do that on warm up depending on the debris. The lubrication will penetrate at higher temps and when it drops whatever is in there (my guess is water) is causing it to rub.

I would start here as well. You can also use a auto stethoscope (at AutoZone for a couple bucks. I usually use it and return it in one fell swoop. Haha).

 

Also. The only place I found them for a decent price is rockauto.

 

Thanks for the thoughts man! I did get a scope at autozone, and found the idler kind of "whirring" but not sure that would compute to a knock when cold. It sounded like that video posted previously of the alternator pulley. I replaced the tensioner this AM, no luck, still making the noise. At least that was warrantied through the Gates, so im not out any money, yet....

 

It may not be the timing chain. The F150 (ecoboost) had this same issue on them. It sounds totally different than what we are hearing on these vids. I know, totally different engine as well as engine displacement but a timing chain would noise would definitely stand out. Hope this helps.

 

I still think it sounds like some sort of air pump.

 

Just replaced the idler pulley, took all of 5 seconds, hoping that was it. The old one didn't seem to bad so who knows.

 

Just remember it can be something as simple as the bearing being washed out to make it sound off. Let us know!!!

 

... And that did not fix it. I'm getting ready to trade the fucking truck in, I'm so frustrated.

 

Here is your option......

Take the truck to dealer, pay the $100 or so for a diagnosis, then determine if you want to fix it or then trade in.....

Or spend another $40K....

Then again you maybe in the market for a new rig......

Sleep on it.

 

Well, like my father used to say, "Wait til it falls off, then we'll know for sure what it was."

 

Yeah I just don't know what else it could be. Do catalytic converters make a rattling sound when they're going bad?

 

Sure, but it would likely change with RPM and road surface (bumps), and would almost without question throw CEL codes that were emissions related.


Did you catch Jace's speculative thought that it could be piston slap?