6.4 tip in high pitch whislte

batmantech · June 28, 2013

08 6.4 72,000 miles. On accel tip in has a high pitch whistle if go to harder accel it stops. If I feather the throttle I can get the noise to vary in loudness. All performance is fine. I did visual for exhaust leaks none. checked low press. turbo axial and radial end play ok spins smooth. used chassis ears in bay under load air rush noise at one side of the downpipe/turbo Replaced the gasket and clamp same noise. Checked cooling system press. noise present before system builds any press.

I'm stuck as where to go now. Hotline said possibly turbo failure even with the endplays ok

Checked in bay vgt 99% rpm 1000 can hear what sounds like air rushing noise at the area here both up pipes go to the turbo unable to pinpoint the location.

Anyone have any thoughts on this? any thing would help at this point.

lmorris · June 28, 2013

Have you checked the exhaust gasket where the two turbos join. That heat shield on the top of the turbo can throw the sound to the back.

batmantech · June 28, 2013

yes, I did remove that big shield

Jim Warman · June 28, 2013

Somebodies son has that happening. He and his dad will be changing the right hand exhaust manifold bolts for it. Only one looks broken.

amailloux · June 29, 2013

I had a left hand exhaust manifold gasket blown out making the same noise you describe.

Alex Bruene · June 29, 2013

Right side inlet pipe flex joint leak?

batmantech · July 1, 2013

Finally found it was the RH flex joint leaking. It was blowing down on to the heat shield by the right rear corner of high press. pump cover.

Thanks All!!

Alex Bruene · July 1, 2013

Jeff Clyde · July 2, 2013

I love changing them ! Would do them all day if there were enough of them !

Alex Bruene · July 2, 2013

I love changing them ! Would do them all day if there were enough of them !

Me too... I've got them down to under an hour and a half.

batmantech · July 2, 2013

It took me that long to get the 3 broken, rusted studs out of the manifold. Not to mention the top 5 bolts that needed the flame wrench to remove. Posted Image

(I also did read "cool cats" post on quick removal)

Alex Bruene · July 2, 2013

It took me that long to get the 3 broken, rusted studs out of the manifold. Not to mention the top 5 bolts that needed the flame wrench to remove.

(I also did read "cool cats" post on quick removal)

Sorry... I should have added "when the bolts come out".

Mikill · July 3, 2013

I'm down in Texas and we have a hard time removing some of these exhaust bolts and nuts on the 6.4 so I can just imagine how it is up north.

6.4 is probably one of the worst engines ever made as far as work trucks go. We don't see too many problems with personal vehicles but these fleet trucks have been gone thru several times.