Strange noise again

fastbee · Aug 9, 2014

I battled a whining noise for weeks a while back, replaced cold side CAC tube, turbo outlet boot, installed up graded up pipes from Rudy's and finally made it go away by replacing the turbo. Later on I installed a 4" TBE. Everything was fine until one day I started getting a screech/chirp sound. My first thought was something in the accessory belt path. Replaced a bad idler and went ahead and installed a new tensioner and belt as well. No change. Replaced the EGR delete pipe and gasket, no change. Pulled apart the exhaust and refit, no change. Installed new downpipe clamp, no change. I can't seem to pinpoint the noise, it's like it's everywhere in the engine bay. Seems to be more in the turbo area, but I can't locate it with a piece of hose or stethoscope. The noise is quieter when I'm under the truck, so I don't think it's the manifold to up pipe connection. No noise at idle, only under load. I can have someone power brake the truck or block off the tail pipe and the noise comes back. Any ideas? I'll try to post a video later.

fastbee · Aug 9, 2014

6.0 noise: http://youtu.be/-4xlMLyPGm8

Trqmnstr · Aug 11, 2014

Sry this is no help at all but on my phone it sounds like you have a seriously big cricket somewhere in the engine bay. Lol

Almost sounds metallic to me but once again im listening on a i phone speakers.

webb06 · Aug 11, 2014

In the video when the noise is pulsing, are you keeping the throttle steady? Or are you making it pulse?

Definitely sounds like an exhaust leak from inside the truck

fastbee · Aug 11, 2014

Trqmnstr - it's not just your speakers...it does sound metallic. It's quite shrill at times.

Webb06 - I was pulsing the throttle to show the difference. When it first starts out from a cold start it is a chirp, like a belt chirp. As boost/rpms increase the sound becomes constant.

Could a failing turbo make this noise? I'm at a loss. When I've had exhaust leaks in the past there was some indication all the time, this one is quiet at idle and goes away when I get on the go pedal hard.

fastbee · Aug 11, 2014

Found something interesting today on the way home from work. If I did a WOT blast the noise went away for a little bit. I'd lay into it and accelerate from 20 or so up to 80+ then slow down. As I started to accelerate normally again the noise wouldn't be there. It would come back in a mile or so and I could blast it again and make it go away. I hit it hard on the road outside the entrance of my subdivision and was able to get all the way to my house without the noise, which hasn't happened in weeks.