Normal break in?

[JThacker]

I now have about 10000 miles on my 04. 5 600 and I have noticed the engine noise has changed somewhat. It now seems as though I can hear valve train rattle a little all the time, the clickety-click goes away when you are not on the throttle and is more pronounced when the engine is pulling like going up a hill. The noise is rhythmical and not random at all, it is not loud, you have to have the radio off and listen for it but I swear it used to not be there. I don't have any white smoke issues and am getting all around about 15-16 mpg, I am concerned because I thought this could be injector knock. Thanks, Jay

 

[Alan Reagan]

I think it is the injectors and pilot injection you are hearing. The injectors, pump and engine will have a little diesel knock. I've noticed mine getting a little more pronounced at 6000 mi. But it's still pretty quiet. Under no load, it's very quiet but once I hit a hill or start acclerating, I get the "ping" knock like a gasser with low octane. At 10K, you've reached the break in mileage for the Cummins. Everything should be seated and enough wear on the components that you could go to synthetic oils if you want. My point is that the engine was very tight from the factory and now that it has some wear, it will sound different and probably a little louder.

 

[Scooby]

With my second gen, the motor quieted down after break-in (which happened after about 30,000 miles) The first 27K miles were basically unloaded and the last 3000 were heavily loaded (cross-country move).



The 10,000 mile break-in rule is subjective. Some (with heavy towing) break in much sooner, while other motors with little to no load take much longer than 10,000 miles - I wouldn't put synthetic in just yet if you fall into the latter catagory.



My 04. 5 has been making that pinging noise basically since new - it sounds like a gasser on poor fuel.

 

[RPotter]

I'm noticing the same thing with mine, now have 15K on it. BUT, absolutely no complaints. She goes like a bat outa you know where. Plus, I have noticed my mileage increasing about 2mpg after 14K miles. Just took round trip to Boise, total about 1200 miles, averaged around 18. 8. And that's crusing about 73 mph, empty of course. They say it gets better after you get past 20K in miles... . we'll see.