Three UOA, Rotella T3 & Delo LE 15w40, 12.7L DD 60s

San Antonio,TX
 The vehicle is our 1996 Prevost XL40' chassis Liberty motorhome. It has a 1995 DDEC3 12.7L 470 hp Detroit 60 series w/83,900 total miles since new when sample #3 was sent to OAI Aug.of 2018. We purchase the bus <6 yrs ago with only a few mx records. Sump capacity is 10 gals. It has a dual oil filter setup from the factory. Fleetguard #LF9620 Venturi Combo(ff & bypass) oil filters were in use for all 3 reports. Likewise for the Fleetguard air filter element that was new June of 2014 @ 68,100 miles. We keep it in our carport at home, so I can mess with it anytime. Verturi oil filter link We use the bus almost exclusively in the warmer months of the yr. We go from our central TX home to the mtns of CO occasionally. Mainly we use it to pull a 9k lb enclosed race trailer around the state of TX to go drag racing. The bus weighs 41k lbs wet, so combined we're @ 50k lbs. We rarely go faster than 65 mph. It gets about 7.5 mpg. The tranny is a 6sp Allison B500. The only reason OAI has ever flagged something (see in report #1) was because I had a mix load in it, 80% Rotella T3 & 20% Amsoil AMO. The Delo LE oil load in reports #2 & #3 was left in place until Oct of 2018. Runtime when changed to what's in it now was 38 mths with 9.5k miles. I did NOT take a sample. Why did I change the oil? Because DDC recommends it when the TBN drops to less than 1/3rd of the virgin #. Delo LE starts life with a TBN of 12. Mine was below 4 when I changed it. In Oct of 2018 we installed 10 gal of Mobil Delvac 1300 Super 15w40, again the dual Fleetguard# LF9620 oil filters, but this time a Donaldson Blue air filter# 5065 with nanofiber technology. Why the switch to Mobil? In 2018 they had a mail-in rebate program, combined with a NAPA sale, I purchased 25 gal for $5/gal. Mobil is doing it again in 2019, but their not as generous. As of today this load/setup has 4500 miles on it. The next sample and report will probably be around Nov or 2020. Nonofiber filter link What do ya Think? All lubes were 15w40
Lube       Rotella     Delo    Delo 
Date        8-15       8-17    9-18
Lube miles   8k         5k     7.5k     
Vehicle    76.4k      81.4k   83.9k      

Iron         16.........9.......15
Copper        7.....…...3......….3
Alum          0.........2...…....2
Lead          3..... ...1...…..….1

Silicon       6...….....7...……...8
Sodium        6...…...….2.....…….2
Potassium     6.........0...……...0

Molybdenum   11........81...……..74
Boron        67.......453...…….371

Magnesium    66.......341......356
Calcium    2930......1640.....1534
Phosph     1106......1094.....1005
Zinc       1434......1254.....1138

V100C      14.6......13.6.....13.4
IR Oxidation 19........13.....….14
IR Nitra      7.........6.....…..7
TBN        6.50......5.53.....4.09
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Staff member
Indianapolis, IN
Fe around 2ppm/1k miles; that's completely in line with expectations for this engine series. The other metals are low. The contamination is low across the board. The TBN is strong. DD publishes condemnation limits of Fe at 150ppm, Cu and Pb at 30ppm. (no limits for Al and Cr). You are WELL below those thresholds. 15k miles is easily doable. Heck 30k miles is probably within grasp. You could quadruple your OCI (around 7.5k miles) out to 30k miles and still be very safe. I would not advocate for extensions jumping directly there, but do it in this manner. 15k miles; a couple UOAs. 22.5k miles; a couple UOAs 30k miles; UOAs. 10 gals and 2 filters are not cheap OFCIs. As I recall, you're averaging perhaps 5-7k miles a year? I'd say do the OFCIs every 3rd year and save yourself some money. Yes - I hear the objections already ... Oil changes are "cheap insurance". Well that is true ONLY in the absence of information. The UOAs are saying that OCI extensions are not only OK, but would support a huge fiscal savings and still provide great wear control. One UOA each year is far cheaper than 10 gallons of lube and a couple premium filters; that's for sure! And once the comfort level is achieved, you can probably forego the UOAs below 25k miles. Great engine in a really nice rig. EXTEND the OCIs! For reference, this is taken from the UOA normalcy article: (scroll down to the DD S60 section)
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Thread starter
San Antonio,TX
Dnewton3 and everyone, thank you for your input. I value it. I've read the CIWMB report a few times over the yrs, very cool. I'd like to see this sort of study done today with todays engines, filters and oils? DDC has a pdf, DDC-SVC-BRO-0001, dated 2018. In it there is a UOA section, 4.6, and a table titled: "Single Sample UOA Warning Limits". The #s are a little different than what you described. That's where I came up with my limit of 4.0 for TBN. DDC-svc-bro-0001 pdf link
Looks great Jetman. Thanks for the good read about the DDC info. We have 5 S60 engines in our fleet 2 pre EGR and 3 EGR no DPF. They have been very reliable with the exception of the 14L 525 hp version. Been overhauled once due to coolant ingestion, and 2 cylinder heads and 2 blown head gaskets and 2 sets of injectors. All the other ones are untouched. It's an 80,000 # tandem axle pierce aerial fire apparatus 2008 MY
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