This is my first diesel, and I've always heard that diesels will turn the oil black with soot after very few miles. I've even heard of some 600 owners stating this as well. But my 305/555 will go 3000 miles before the oil darkens enough to even tell the difference from unused oil.

Is it the new injection system or the CI-4 oils that have reduced the discoloration of the oil?

Thanks!

 

I would say you have a good engine that does not have any slobbery injectors. CI-4 oil does maintain clear oil color, it is supposed to have the capacity to handle more soot.

I would bet that you are getting very good mileage economy.

 

The 305/555 trucks are noted for beeing real easy on oil. My 325/600 on the other hand had black as tar oil with only 300 miles on the truck new.

 

Same here my 600's oil has been black from the first time I checked it, the day I brought her home.

 

I'm amazed at how well these engines seal. I've been running Delo and changing at 10,000 miles. I don't have to add a quart between changes and the oil is a light brown at that mileage.

Wetspirit

 

After 5k on Delvac 1/Mobil 1 Truck & SUV (same thing), the oil is as golden and clear as it was when I poured it in. Before I installed the bypass filtration system, the farthest I went was about 7500 miles between oil drains, and even at that point, the oil was not discolored. The reason the oil stays so clean on 305/555's is that they have all the benefits of HPCR technology, without any of the typical emissions features that dirty the oil - such as a closed crankcase ventilation system, EGR, catalytic converters, etc. I'm not sure what exactly on the 600's is causing the oil to blacken early, but that's sure unfortunate. On my last oil analysis, after 7000 miles my soot percentage was 0.1%