High Pitch Whistle

[714Rick]

Have an ISL 400 in a ‘06 Monaco Camelot. Recently had the fuel line bracket recall completed at the Cummins dealer in Oklahoma City. After about 400 miles on my trip back to southern California, my wife who has very acute hearing, started complaining about a high pitched sound from the engine when under power.

I am not able to hear it, but she says that as the load on the engine increases, the sound gets louder and higher pitched. Co-incidentally, at the same time, I got about a 15-20% improvement in fuel mileage. Probably will take it to Cummins in LA area but am wondering if anyone has any ideas.\

Rick

[Mike Canter]

Most likely your wife is hearing the turbo spin up when the motor is under power,

[quikduk]

Mike might be right. I am personally sort-of deaf when my wife speaks to me though...

If there was a leak, you would lose power pronto.

Still, it would be a good idea to check it or have it checked when you get back.

Since you live in SoCal (as do I), might I suggest Redlands Truck or Colton Truck Terminal Garage? Both are reputable and both work on a LOT of DP's.

[Mike Canter]

A true funny story....my 92 year old father-in-law kept on complaining about a whistling noise in his Buick. He took it into several Buick dealers and they could never find anything wrong with it. He complained to me on the phone weekly. Finally I went and visted them in Texas and he took me out in the car to let me hear it and we drove and drove and drove but no whistle. The next night I picked him and his wife up in my car and while driving he suddenly told me I had the same whistle in my car. I then realized my 89 year mother-in-law was sitting in the back quietly whistling as we were driving. I nearly had to pull over because I started laughing so hard. Later I asked her to not whistle in the Buick while they were both driving. Guess what the problem went away.

[Ray,IN]

Please return and inform us of the whistle source when you find it, I for one would greatly appreciate duplicating the condition and receiving that mileage increase.

Mike, that is a classic!

[714Rick]

Took the coach to Cummins So Pacific.
They found the problem was a broken bolt attaching the exhaust nanifold, which required replacing a warped exhaust manifold.

Thank God for Cummins warranty.

Don't know whether the milage is affected or the last 700-800 mile was just a quirk. Have not had it back on the road since the repair.