Ford Power Stroke Nation banner


1909 Views 6 Replies 7 Participants Last post by  MJ Racing
I know it's been discussed on here more than once but I need to know! My brother has a 2005 Dodge 2500 4x4 with a Cummins and a 6-speed manual trans. He lives in Las Vegas where as you know it gets very hot. He bought the truck new and used Rotella oil the first 5K miles and then swithed to Amsoil. He contacted and told Amsoil what he used the truck for which is moderate towing and around town use. Now I know that they didn't develop a special blend of synthetic diesel oil just for him but they did need to to know everything about his truck. They sent him the required amount of oil and their oil filter and told him to run it for 25K miles before he changed it. At 22K miles he noticed that the engine was 1 quart low on oil so he changed it and the filter. He then put 25K miles on this oil before he changed it and the filter. The oil was just as clean at 25K miles as it was when he poured it in. Amsoil also has a 100% guarantee that they will replace your engine for free if it fails because of their oil anf filter. Big diesel semi's are running 100K miles between their oil changes with the same guarantee. My brother also said that his truck ran quieter and had more power almost instantly when he used Amsoil the first time. My brother is not one to say these things if it wasn't true. Has anyone on here put that many miles on Amsoil diesel oil between changes? Sorry to be so long winded but inquiring minds gotta know!
1 - 1 of 7 Posts
I would not recommend running any oil over 5,000 miles in your Powerstroke without doing a UOA (used oil analysis) to establish some historical records. You don't want to start running extended oil drain intervals without establishing a baseline and determining how the oil properties are holding up as you increase the drain intervals over 5K. Synthetics can be run 10K+ in some applications but the Powerstroke's HEUI Injection system is harder on oil. With a chip in a 7.3L you can easily hit 3000+ ICP and 7 times that at the injector - even higher in a 6.0L. It is quite common for 7.3L's with some Dual HPOP setups and 6.0L's to shear the viscosity down to a 30 weight oil before 5K.

I'm not saying that you will always have to do a UOA, just do them long enough to establish a history and at a point to where you feel comfortable with the results.

Not knocking Amsoil - but the Powertroke HEUI Injection system is much harder on oil than your brothers Cummins. You can do a search here or on and see some Used Oil Analysis reports running Amsoil in this application.
I agree with WB in that I would do UOA in a 6.0L at about 5-6k miles and set a baseline with your vehicle by doing oil samples. Once you get a history going you will have set a precedence with your truck and then you could set your oil change intervals based on the UOA history. Its also a good idea once you set your OCI to do a sample when you change the oil to monitor your engines internals as much as the oil. Your looking for high wear metals, coolant, fuel dilution etc not just oil viscosity.
1 - 1 of 7 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.