Engine brake, air rushing sound
My coach runs fine but I have a question/concern about a noise I hear whenever I use the compression brake. I usually only can hear it when I am in a tunnel or passing close to a bridge wall or jersey barrier. It is the sound of air, a lot of air moving. Someone on the Cummins forum suggested it was a symptom of an exhaust manifold leak but when looking in that area with a flashlight, I see no evidence of soot or air leakage.
Is this merely a characteristic of the 2007 and later clean diesels? Do any of you with the ISL of that year or later hear the same noise? Is it some attempt by Cummins to quiet the compression brake....perhaps due to the DPF muffler?
'07 Country Coach Allure 470 Siskiyou Summit #31578, Cummins ISL 425; 2014 Ford F150 toad; Air Force One Toad Brake.
Glen Allen, VA; Smith Mountain Lake, VA.