What could this metallic rattle be? Description has video

[OpenYota]

Shared album - Christian Moule-Smith - Google Photos

The sound only happens when I accelerate and mainly from 1500-2500 rpm (1700 rpm is when it really starts) and seems to be from the front engine bay.

I don’t see anything loose around my cats or heat shields, could it be a torque convertor issue?

Any help on where to look would be appreciated.

 

[LrndTheHardWay]

Find it? Sounds like a shield or something, could one just be a little loose?

 

[50thStateTRDPro]

Shared album - Christian Moule-Smith - Google Photos

The sound only happens when I accelerate and mainly from 1500-2500 rpm (1700 rpm is when it really starts) and seems to be from the front engine bay.

I don’t see anything loose around my cats or heat shields, could it be a torque convertor issue?

Any help on where to look would be appreciated.

Might be caused by the last two altoids rattling in the can. Lol. I’d guess it might be a heat shield too. Good luck.

 

[brillo_76]

Heat shields break around bolt. sometimes you have to use fender washers to hold the heat shields on the body. If you still have the heat shield on the cats.. They too will rust and come loose mostly have to use stainless steel radiator clamp to stop that from rattling..

 

[itsnotbroken]

It's one of the heat shields above the exhaust system.
Install fender washers on BOTH sides of the shield.

 

[OpenYota]

It's one of the heat shields above the exhaust system.
Install fender washers on BOTH sides of the shield.

I checked the heat shields around the cats and muffler and they all seem tight and the bolts haven’t rusted out.

 

[GhostRing]

100% in the engine bay? Does it only happen in motion?
If you pop the hood and rev it at the throttle body, can you hear it clearly?

 

[phattyduck]

Might be caused by the last two altoids rattling in the can. Lol. I’d guess it might be a heat shield too. Good luck.

"BBs in a tin can" is the normal description of knock/ping in those situations... Might be worth putting in a tank of 91/93 octane to make sure your engine isn't eating itself. The stock ECU ignores the knock sensor below ~3k RPM, so it won't pull timing down there if there is ping/knock.

-Charlie

 

[OpenYota]

100% in the engine bay? Does it only happen in motion?
If you pop the hood and rev it at the throttle body, can you hear it clearly?

I can't be 100% sure it's in the engine bay but it sounds very much like it when I'm inside the car.

When revving it in at the TB with the hood open in park I do not hear the sound; I also put the rear on jack stands the other day and put the car in drive and revved it to the 1500-2000 RPM range and still didn't hear it so it only happens when in motion and under acceleration.

 

[OpenYota]

"BBs in a tin can" is the normal description of knock/ping in those situations... Might be worth putting in a tank of 91/93 octane to make sure your engine isn't eating itself. The stock ECU ignores the knock sensor below ~3k RPM, so it won't pull timing down there if there is ping/knock.

-Charlie

I'll give the 91/93 octane gas a shot next time I need to go to the gas station - but I have accelerated the car above 3k RPMs recently so wouldn't it have set off a knock code?

 

[Zhehan]

The heat shield on the crossover pipe behind the engine had rusted away from the mounting clamps on the passenger side in the engine bay on my 4Runner. It was thin and feathery at the edges, resting directly on the crossover pipe. It buzzed under acceleration exactly like yours. I used a stainless hose clamp to wrap around the end and secure it into place. Problem solved. I think this is a rather common problem.

I had a buddy help me with the project since it's in an awkward place to work on. If you want a picture, let me know. Hope this helps.

 

[OpenYota]

The heat shield on the crossover pipe behind the engine had rusted away from the mounting clamps on the passenger side in the engine bay on my 4Runner. It was thin and feathery at the edges, resting directly on the crossover pipe. It buzzed under acceleration exactly like yours. I used a stainless hose clamp to wrap around the end and secure it into place. Problem solved. I think this is a rather common problem.

I had a buddy help me with the project since it's in an awkward place to work on. If you want a picture, let me know. Hope this helps.

I would greatly appreciate a photo of the location of that heat shield.
I've poked around the engine bay and underneath too many times now and I only see the foam(?) heatshield media and not any metal but I may also just not be seeing it entirely.

 

[phattyduck]

I'll give the 91/93 octane gas a shot next time I need to go to the gas station - but I have accelerated the car above 3k RPMs recently so wouldn't it have set off a knock code?

There's no code for knock, it would just pull timing up there and run "fine"

Check those heat shields closely and try higher octane fuel. Either one would be a cheap fix.

-Charlie

 

[Zhehan]

Here's the crossover pipe, heat shield and hose clamp fix. Yes, I know I need to do valve cover gaskets. It's also really hard to get a picture of that location with your phone. Hope this helps.