Under hood whistle

[FrankG]

2016 2500 Laramie, 4x4, 68rfe, 76,000 mi. In the last month we traveling about 4,000 miles, with a 2,300 mile trips. We live 20 miles from anything except cattle and goats, so no short trips here. All services are up to date including the 68rfe service and CCV filter. The issue is about 3 times in the last month once accelerating from a stop, once deacceletering and braking to a stop. And today, flat road 50 mph 5th gear pulling a small 3500 lb trailer. Out of nowhere would come this rather loud whistling sound from under the hood, lasted about 20sec and I couldn't make it go away, but it did on its own, not abruptly but tapering off. Thinking an egr system issue, any thoughts.

 

[nukegm]

comrade. i have a 2002 5.9 . it had same symptom as you describe. it was a " boost " leak. the whistle/ hissing was the turbo leaking past a clamp.....just my .02 cents. cheers!

 

[Ozymandias]

Could be a leak, check the boost hose that is right under the intake elbow from the air filter coming down.
Sometimes they touch and that's chafing the boost hose.

 

[gsbrockman]

The puzzling part is.... @FrankG also said it did it whilst decelerating, too.

I’m wondering if it might be exhaust manifold gaskets.

 

[FrankG]

Thank you all for your responses. I will dive into the intake and exhaust plumbing. Yes, it is confusing and being so hit and miss makes it more difficult. Yesterdays incident gave me a little more time to react to it, throttle position (boost or not or the exhaust brake activation) had no effect. This is why I was thinking the EGR system. From what I understand EGR system cleaning is not part of the scheduled maintenance on the 2016 and I have been avoiding it. As I think about it the only consistent is it has only occurred about 10 miles down the road after a cold start up. That's if you call a start up on a warm summer morning in sunny Florida "cold".

 

[Cummins12V98]

Could be a leak, check the boost hose that is right under the intake elbow from the air filter coming down.
Sometimes they touch and that's chafing the boost hose.

Like this??