I have two Pentastar engines. One in my 2018 pacifica and I use Amsoil Signature 0w20 oil in it. Tht is Amsoil's 25,000 mile oil by their claim. The oil change indivcator and manual say 10000 miles for a change. My other PEntastar is in my 2020 Ram 1500 Longhorn 4x4. I have been using 0w20 Shell Rotella gas engine oil in it. The Pacifica has about 62,000 miles on it and the truck about 31,000 miles. I do an oil analysis using the AMsoil kits on all oils I change for fun and information.
I ignore the time interval for an oil change since my vehilces get run decent distances and get fully warmed up when used..
I also have A JCB backhoe/frontend loader with a 76 hp PErkins diesel engine and a small Misubishi 4wd tractor with a 3 cylinder 23 hp diesel. These get few hours on them and often don't get warmed well warmed up. The JCB has a 11 or 12 qt sump so a lot of spare oil/additives for the engine size. The little Mitsu has a 3 qt sump which is large relative to hp.
The two pieces of equipment get tested every year or two and typically changed every 6 or 7 years. I change the car and truck nominally at 10,000 miles which is usually 12-14 month interval. Once I ran the car 15,000 just to see the oil analysis so I could choose to run a bit longer than 10,000 if changing was inconvenient.
I change my own oil. I have never had a bad oil analysis and everything has significant life left in the oil based upon testing results. THe diesel engines still have good base numbers and very low particulate load and all additives still are at sufficient levels. Viscosity is alway OK for all tests/engines, I have never seen and notable water reported in a test nor have either the gas or diesel engines had any fuel dilution issues. I never see condensation on a dipstick when I pull it and never have seen milky oil except in my Polaris 700 which had the water pump and oil pump onthe same shaft with a seal between to keep them separated and it often failed. That engine was often used with 'mayonnaise' like oil do to water in the oil because it was all I had to plow snow because it was all I had to [plow the snow at the time. It never seemed to damage the engine and when last repaired it didn't use any oil and ran fine and I sold it with about 7000 miles/800 hours of hard use, with no apparent bad effect.
AS I said, I do the analysis for fun and at bout $20/test it is cheap fun for me. I hate throwing away good oil because changing is not a fun job and getting rid of the oild oil is a pain too. I am not an environmental fanatic but it also seems like a good idea to minimize unnecessary oil changes.
In the past I had an ecodiesel and a couple VOlvo inline 5 cylinder diesel engines in my boat and I always used oil analysis in them too.
None of my engines now or in the past are high/hour/mileag and none used pervceptable quantities of oil so no oil was added between changes.
My conslusions after 15+ years of doing analysis and using high quality synthetic oils is time is irrelevent in oil changes as long as your machines get warmed up periodically. I tend to stick with the mileage intervals recommended by the manufacturer but feeel comfortable running over 20% safely if timing for the change is inconvenient. If you use good synthetic oil of a name brand quality meeting the viscosity and specs set by the manufacturer I see no reason to change sooner than the mileage or hour limits set by the manufacturer. Dealers or oil change outlets recommending more frequent changes are feathering their own pockets or are just old fashioned and not up to date. Remember Kendalls big advertising slogan in the 1950s was "the 2000 mile oil" when many were recommending 1000 mile oil changes. OIls, additives, engine metallurgy, fuel properties and fuel quality at retail stations have all improved significantly. in the last 60 years.
On a separate subject I am generally not buying Amsoil products for routine oil change oils anymore since so much good stuff is available from the major oil Companies like Shell, XOM, CHevron, TOTAL etc at a much cheaper price. I still use Amsoil in snowmobiles, motorcycles and for 2 stroke engines. I also use their synthetic greases and transmission lubes and hypoid oils all things where the major oil COmpanies don't have similar stuff generally available at cost effective retail outlets.
All the best,
