Cummins ISL Engine Brake whistle

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...Someone on another forum suggested it was the variable geometry turbo used on my engine. The vanes on the turbo flatten out during application of the engine brake causing the sound...

smlranger: I'm encouraged to hear you cite that diagnosis. That is the same thing the Cummins mechanic said the last time he listened to it in the shop. I have not had a chance to get out to the MH and look for evidence of soot on the exhaust manifold yet ... it's been to <&%^#)?@> cold here lately ... so an exhaust manifold leak could still be a possibility, too.

Thanks, guys!

\ken

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Update: After three shops told me the "whistle" I was hearing was normal, I noticed a change in the pitch while in the RGV this winter. There was a bit of a dis-chord ... as if two pitches were not in the same key.

It was enough for me to take it to South Plains Cummins up in San Antonio. They discovered that I did develop an exhaust manifold gasket leak (between cylinders three and four). The team there replaced the gasket, but the whistle did not go away! Only the dis-chord was gone.

Head's Up: Some of the VGTurbos will make their own whistle (that whistle comes through the exhaust (in my case). The whistle sound that is caused by the bad gasket comes off the driver's side of the engine. Both whistles together sound terrible, especially when standing immediately behind the engine. One whistle (from the turbo) sounds like music!

All fixed now. Turbo checks out great! WooHoo!

\ken

[Smitty77]

Thanks for sharing your findings! Glad the VGT is healthy too... And yeah, the ISL exhaust manifold club now counts you as a member! Lucky the exhaust manifold was not warped or cracked, as that is another level of 'the club'...

Travel safe, and learn how to whistle along with the VGT as you go down the road...
Smitty