Cummins 400hp high pitch whistle

[nuckels11]

We have a Cummins 400 hp ISI engine in a 2005 Holiday Rambler Endeavor and have noticed a high pitch whistle sound at low rpm. Does anyone know if this is a normal characteristic of this engine? Or has anyone else encountered this noise with this vehicle?

[OneRVer]

The first thing that comes to mind is your turbo. Is the sound coming from the engine area?

[nuckels11]

Yes, it does appear to be coming from the engine area.

[akadeadeye]

We had this happen. Took it to a Cummins shop. A clamp had broken on the boot either to or from the turbo.

Don

[Barlow46]

You will find many posts about this being a normal turbo sound at idle. I talked with techs at Cummins South Ocala and they said the same thing, "normal sound at idle". I would still take a look at all connections around turbo to insure there are no leaks if possible.

[OneRVer]

Quote:

Originally Posted by Barlow46 You will find many posts about this being a normal turbo sound at idle. I talked with techs at Cummins South Ocala and they said the same thing, "normal sound at idle". I would still take a look at all connections around turbo to insure there are no leaks if possible.

I agree. If this is a new sound it needs to be checked out.

[rpasetto]

Could be a pinhole of micro crack in exhaust system; you may be hearing the whistle of a small amount of exhaust gases escaping.

We had such a sound on our 2003 Dynasty. Cummins replaced belts at first- no change; then had a tech ride in the back with his ear near the engine and discovered a crack in the exhaust manifold.

[nuckels11]

Thanks to all who have responded to our question. I listened from inside the coach with the hatch to the motor open and didn't hear the whistle. It seems to be more noticable on the driver side of the coach and near the outside. Any more ideas?

[Barlow46]

Look for "soot" with the hatch open.

[Airtool]

Also ! check the air supply line to the air pump. The air line from the turbo is used to filter the air and also assist in increasing the pump output. This hose can get a crack and it will cause a whistle. The line runs from the intake manifold to the Air Compressor.This is located generally on the curb side of the engine. The other areas have been mentioned.
Have you noticed any decease in your engine performance ?
The you will need to set your park brake,and put the transition in gear. You can then get the RPM's up so the boost pressure can come up.
Always good to use wheel chalks with the park brake.
Someone will need to listen around the area of the engine under the doghouse, while another person depresses the accelerator.

Work safe, Dick.

[JFC]

My wife noticed a whine on our 2007 with the 400 engine. Took it to Cummins and had $6500 in repairs for blown turbo and CAC. All covered by Cummins warranty. Blew replacement turbo less than a year later but didn't take out the CAC Cummins had made. (Couldn't get a replacement from Monaco at the time, they had one manufactured) Second turbo replaced again by Cummins under warranty. They did a complete engine check each time and could find no cause for failure, decided it was a turbo manufacturing problem not an engine problem.

[Diplomat Don]

When I start my ISL, its quiet for about 20-30 seconds and then the turbo spools up and whistles. I believe its quiet for the first 20-30 seconds while the turbo gets oil and loosens up. The whistling is kind of errotic for me......that bad boy is spooling up!

I just replaced my Charge Air Cooler a few months ago (new one included with my radiator) and the new system still makes the same whistling noise when starting cold.

I ordered the Source Engineering cooling fan today, so I suspect I'll hear the whistle even more.

If everything is running well, I don't think you have a problem.

[zman62]

Its just the turbo spinning. I have the same motor and its done it since new.

[Zbugsii]

I had a similar symptom with my ISL400 and it was due to an exhaust leak at the junction of the manifold with the engine. The gaskets had failed and had to be replaced.

I found it by starting with a cold engine, remove the access covers from inside and having my wife start the engine while I ran my hand all over feeling and listening for what was the cause before it got too hot. Found and got it fixed.