i just went to the dealer the other day to look at new heavy duty's, and as i was talking about the cummins w/ the dealer he was explaining that w/ the way the exhaust system works, the emissions crap, computer this and that, blah blah blah...you shouldn't let these trucks idle for more than a few minutes at a time. something to do w/ the particulate filter and some kind of build up of crap during idle.
i just smiled and nodded and went on w/ the test drive. anyway.....anyone know anything about this and why or why not...true or not true. he seemed fairly knowledgeable about the trucks.

and if anyone is interested in a new truck...i think now may be a good time to buy new. they offered me a 3/4 4x4 megacab slt for 21k plus my truck. still owe 9k on mine...so i'd be spending 30k total on a new cummins. very very difficult to say no to...but my wife helped.

 

when you let it idle for long periods of time the particulate filter will clog up with soot. The truck will not enter regen mode unless it is moving.

 

A few months ago, someone started a thread about this exact issue in regards to the 6.7L cummins. I wish I could find it. Anyway, isn't this true for the 5.9L trucks too? I thought that I read in the manual that I shouldn't let my truck idle for extended periods and I have the 2007 5.9L Dodge Ram 2500. It said something about idling not reaching high enough temperatures to burn off all of the carbon or something in the engine.

 

The 5.9 issue was with unburnt fuel washing the oil off the cylinder walls and scoring the cylinder.

 

so how long is to long for a 5.9 to idle?

 

I don't worry about mine the overhead will let you know when the filter is getting full.