Cummins isb 275hp turbo whine

JBDISCOVERY · 04-26-2011, 06:57 PM

I HAVE A 99 Discovery with 84000 miles on the OD. The Cummins ISB has a turbo whine at 50 mile per hour to 60 miles per hour. Is this something that I should worry about? It is bothering while cruising along. Thoughts on this.
JB

sjholt · 04-26-2011, 08:17 PM

Are you sure it is a turbo whine?
Does it vary when on and of the throttle?
Maybe it is a rear end whine?

Perry White · 04-27-2011, 01:33 PM

If you have a rear engine diesel you can't really hear the turbo up front. Are you sure your not getting a high frequency wine from your alternator thru your radio?

JBDISCOVERY · 04-28-2011, 06:05 AM

Fellows, thanks for your input. No, I still hear the whine without the radio on.
Also I just changed the lube in the rearend. The whine at 50 to 60 mph is the same as when the engine is at idle at a red light. Any thoughts on this.
JB

Wizard · 04-28-2011, 06:11 AM

Another thing that bit me, check the volume on your backup camera monitor.

Dacotah · 04-28-2011, 08:57 AM

Wizard has a good idea. Right after we bought our coach, I kept hearing strange sounds from the back of the coach, it was the microphone on the camera amplifying everything in the rear. If you are concerned about the turbo, lift the bed up, have someone else drive and listen from the bedroom for turbo sounds. Do not try this on a dirt road for obvious reasons. DACOTAH

J Walker · 04-28-2011, 09:41 AM

There are the usual things to check in addition to those already mentioned. Is the whine RPM or speed proportional or related? If you have Silverleaf VMSpc it will tell you the turbo boost and as I understand it that will give you an idea of the turbo rpms. At idle you should have little or no turbo boost meaning that it can't be whining. Other accessories might be the problem like the air compressor, alternator, or water pump. However you access your engine give it a close up listen and I believe you will discover something.