My new 07 5.9 dually makes a chattering noise in the morning when about 35 degrees out. Under normal acceleration I hear it chatter about 6 times, 30 seconds go by, I hear it again. It does it about 3 times. After 10 minutes of run time it stops. It's not a valve noise. To be honest it sounds like one of those air machine guns like at a carnival, LOL. The dealer says it's normal, that it was some kind of purge valve opening. It doesn't do it on 50 deg mornings. I traded an 06 5.9 & it didn't do it. The dealer said he took another 07 5.9 out & it did it too. Anyone hear of this??

 

I haven't heard of such a noise on mine.

 

Called several dealers, one dealer took two new trucks, and he said he didn't hear the noise. I called another dealer, he also told me along with my selling dealer, that they were having the same problems with the 07 5.9. He said it sounded like a valve noise and that it would do it the same frequency that I noted previously. He said, as long as it doesn't throw a code, don't worry about it. So I am not the only one having this problem. I also wrote an Cummins an e-mail. As I said earlier, one dealer said that it possibly could be a purge valve. But one dealer said that the 07 5.9 didn't have a purge valve. It sounds just like the intake manifold heater relay trying to come on, but chattering, because it's not supposed to come on above 19 mph. I will keep y'all updated when Cummins writes me back.

 

I believe what your hearing is your grid heater cycling. And will not only draw alot of amperage when it cycles on and off but also, make the idle speed fluctuate( spelling bee champ 1982) a bit. This should happen when its 58* or less, upon start up. When it is cycling, you'll here the engine drop a few rpm and see the lights dim when the heaters come on. It will sound a bit different during this until engine temp is up. Without hearing your truck, I believe what your saying your truck is doing is completely normal and woulnt think twice about it.

 

In response to air grabber's comment. I am all too familiar with the sound of a 5.9 diesel. I traded in a 2006 5.9. The heater, when it comes on, makes a single clunk noise, and when it shuts off, it makes a lighter clunk noise and does this several times until it is warmed up, all the while, the engine rpm changes, and the ammeter fluctuates. The clunking noise that I am describing is a clunk noise in rapid succession. It does this about four or five times. Every time it does this, the engine rpm does change slightly, kind of like a missing engine. The ammeter does not change at all. This happens, under normal acceleration for about 10 minutes. In the driveway, while warming up, it operates normally just as air grabber described. Being an air conditioner contractor, if a relay on a conditioning unit does this being under a high amperage situation,like the heater, the relay fries, along with some wiring. I'm sure, Dodge will issue a bulletin on this soon.