A few weeks ago, my truck started making this ultra-annoying metallic rattle between 1100 and 1300 RPM, 2000 and 2150 RPM, and 4000 and above RPM. It rattles regardless of what gear the truck is in, and it also rattles in neutral and if I rev the engine while not moving so obviously it's not a transmission or drivetrain issue. Additionally, it won't rattle until the truck has warmed up for about 30 sec to 1 min. The noise is coming from the engine bay but when I pop the hood I can't pinpoint the noise! It doesn't sound like it's coming from the engine and the truck isn't running any differently. It is very annoying however, it's pretty loud and grating, very metallic. I'd really appreciate any ideas as to what may be causing this noise.

Specs:
1994 Dodge Dakota Sport
3.9 Magnum
2 wheel drive
5 speed manual

 

could be a loose heat shield.

 

+1 to the heatshield! I've seen it too many times.

 

Sorry for asking such a stupid question, but where exactly is the heat shield?

 

It follows the exhaust piping all the way back between the pipe and the body and there might be some pieces attached to the firewall behind the engine.

Just look for peices of thin tin bolted to the body around the hotter parts of the engine/drivetrain.

 

Cheers everyone, there was a broken weld on the catalytic converter heat shield. I just put a hose clamp on it and now the rattle is gone!

 

good. glad that it was something simple...

all of mine a broken, the last time i was under my truck(2 days ago) one of them actually attacked me and i'm getting ready to pull them off and patch them up and screw them back on. the rattle very badly, but my exhaust is loud enough so i don't hear it...

 

Why not just rip them off if they're that bad? They're not really needed.

 

Jury's out on whether you need them....they do protect you a bit when you're under the truck and it's still hot, and they keep the hot exhaust off of tall, combustible vegetation when you have to go offroad and stop in tall grass, etc. I would fix it and put it back on there.

 

since i have no carpet in my truck right now 1 heat shield fell off already and my truck gets about 10 degrees warmer inside now, normally i wouldn't mind but because we have 90+ degrees weather it gets to be to much.