Help me identify this noise, please!

I have a noise that I can't identify. 08 Access Cab, manual transmission, 2.7l 4cyl. There is a metallic "rattle" that appears to be coming from underneath the truck. It mainly is noticeable when the engine is under load and in gear at about 1600rpm, though I've also been able to reproduce it at higher rpms during downshifting. I can't get it to make the sound at all when in neutral. I found and fixed a loose heat shield thinking that was the cause, but it didn't help at all. I have a feeling that the noise is coming from a catalytic converter, but that's just a guess. Does anyone have an idea what this might be?

Here is a video (you might have to turn up the volume a bit to hear it over the road noise):
https://youtu.be/JT1lm52-JVQ


Thanks!

 

Possibly the heat shield/clam shell shield on the catalytic converter. My rivots or what ever is holding the head shield together rusted out and it began to rattle.

 

I don't hear anything except white noise.

That said, I'd be more inclined to think your catalytic converter is failing. 2.7 cats just got recalled, not sure your truck applies.. but I've gone through 3 (and my truck is a 2013)..

 

I agree. I didn't watch it before I answered. But I did have a rattle noise and mine was the heat shield. Just my 2 cents

 

Halfway through video you can just hear it. Like others said most likely the heat shield attached to the cab floor underneath or the actual clam shell shield that goes around the catalytic convertor.

 

Thanks for confirming, it is hard to hear but if you turn up the sound you can hear it right about at the halfway point. The cab floor heat shield was loose (this was the heat shield I mentioned in my original post) but it's all tightened up now and didn't change the noise at all. As far as I can tell the shield on the catalytic converter is nice and tight as well. Is there any way to confirm that either of these are the source?

 

Yeah start up your truck and "torque" the motor. Left foot hard on brake pedal, shifter in D, and pulse the gas pedal with your right foot. Doing this usually causes enough movement/ vibration from the motor to help make exhaust pipe/ shield noise occur. Where I live usually the 10mm nuts will wear/ corrode through the shield and let it hang. Removing the nut and adding a larger washer is a easy/cheap fix.

 

I had a rattle from 1600-1800 but went away after the truck warmed up (usually a few miles). Does your rattle ever go away or is it constantly there?

I ended up changing the oil and spark plugs and then banged on the exhaust trying to find where the rattle could be coming from. After I was done with the oil change and spark plugs, it hasn't rattled since. I don't know if it was from old/low oil or what, but I would at least check your oil and see if its low.

 

Check the shield mounted to the cab floor above the cat

 

This is exactly what I did to fix the heat shield above the cats. Unfortunately the sound remains unchanged.

 

Cold or warmed up doesn't seem to have an effect on the noise.

 

I can't hear shit



srsly it could be heat shield in the engine bay around
exhaust manifold. bang on all that stuff when cold...