Question Is extended idle really bad for a Cummins diesel? Fact or myth?

[Joe Hogan]

In my opinion since there are so many variations in equipment and application, it is best to refer to the specific Manuals supplied with your RV.
If that topic is not addressed call engine mfg support.

Granted this is not the fun discussion path but will give you a defensible documented position should things go wrong.

 

[Racklefratz]

At Gaffney, I asked about this. They said no extended idling. If you must idle, bring the rpms up. I cannot remember but I believe it has to do with DEF

Agree. Our 2012 Tiffin has the Cummins ISL 450hp in it, and extended idling definitely asks for issues.

While at the Tiffin factory service center, we had modifications to the tag axle suspension air pressure work done, which required long periods of engine idling to keep the system aired up.

When we left the facility, we were greeted with immediate DPF warnings that only cleared after we have been at road speeds for a while. The extended idling resulted in clear messages from the system that it didn't like it.