This is about the oil in the Kubota V2203 diesel engine that powers the PowerTech 17.5kw generator in our 96 Prevost Liberty motorhome. It has 13,096 hrs on the hobbs. 2 yrs ago when it had 12,868 hrs, I sent an oil sample to a lab for analysis. The results indicated severe bearing wear, high amounts of lead and copper. So I changed the rod bearings, and 1 yr and 100 hrs later the results were excellent. Wear was normal.
Recently, I sent in an oil sample from the Kubota to Blackstone Lab for analysis. The oil, Mobil Delvac 1300 Super 15w40, is 2 yrs old, w/222 hrs. The oil filter is a 2 yr old Fram XG3593A. It has been 2 yrs and 222 hrs since I replaced the rod bearings, and put this oil, and oil filter in place.
Got the results and they are excellent again. Blackstone Lab comments: DON: An impressive first report for this Kubota. This oil was in place far longer than the ~85-hour run universal averages for the V2203 are based on, yet metals are within just a ppm or two of universal averages. That means this engine doesn't produce much metal during each hour of operation, a sign that internal parts are getting along very well together. The viscosity tested a hair below the 15W/40 range, but a marginally thin viscosity won't bother anything and clearly this engine didn't mind. The TBN of 7.4 is strong, since 1.0 or less is low. Feel free to run 275 hours.
Rumor in diesel engine circles is that it's normal for rod bearings to need replacing when a diesel engine reaches half life, which looks to me to be at about 13,000 hrs for this wonderfull engine.
The genny hasn't given us any problem(s) in the almost 7 yrs that we've owned it.
The Kubota doesn't consume any oil so no makeup oil was added. I did change the oil and filter(needlessly) when I took the sample this time.
In the future I plan to do an oil and filter change and send in a sample for analysis every 3 yrs or 300 hrs, whichever comes first.
I use 3 different labs for analysis of my vehicles lubricants and coolants: OAI-Oil Analyzers Inc, JG Lubricant Services, & Blackstone Labs.
Below are pics of the 3 UOA reports from the 3 different labs that I use. The 1st is from May of 2018, which shows the high lead and copper. The 2nd is the excellent June of 2019 report that was done 100+ hrs after the first. And last is the June of 2020 w/220+ hrs on the oil and filter.