Full Synthetic oil in 2016 Dodge diesel

spoon059 wrote:

Lynnmor wrote:
How about that! Now try to learn that Diesel Exhaust Fluid has NOTHING to do with regens. It is injected into the exhaust to reduce NOx. The extra fuel is used to burn out the DPF. Oh, and welcome to the condescending club.

Before Cummins introduced DEF into the exhaust system, the way they reduced nitrous oxides was with use of the EGR. The EGR routed a lot of exhaust gas back into the engine to reduce the total nitrous oxides coming out of the tail pipe. That caused the oil to get very dirty, very quickly. As a result of the very dirty conditions, it required shorter oil change intervals.

In 2013 Cummins introduced DEF as a means to reduce nitrous oxides in the exhaust. Using DEF to reduce those nitrous oxides resulted in substantially less involvement from the EGR valve, which meant less exhaust gases going back into the combustion chamber, which meant the oil wasn't getting as dirty nearly as quickly. As a result of cleaner conditions, it allowed longer oil change intervals.

Hopefully I don't get a nomination into the "condescension club", and hopefully you understand the argument that several people are making.

Yes, technically the DEF has absolutely nothing to do with the engine oil, but the technology of DEF has a direct impact on the EGR, which has a direct impact on engine oil.

Spoon, you are 100% correct, but left out one other bit of info. Since the pre-DEF trucks utilized the EGR more, it clogged the DPF a lot sooner since cooling the combustion temps creates more soot. Since the DPF is being clogged a lot sooner, the truck needs to regen a lot more. Since the Cummins engines squirt fuel after combustion to get the DPF hot enough to regen, the oil will get diluted with fuel more often which requires the oil to be changed more frequently.

With addition of DEF, the EGR is not used as much which creates less soot which causes less regens which means less fuel dilution in the oil which equates to the engine oil not needing to be changed as often. The DEF system does not directly effect oil contamination, but it does effect it indirectly due to not needing to use the EGR as much.