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#16
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Oil standards have changed as engines have changed, as mentioned above. Modern engines run different combustion temps, have catalyst systems not present on older cars, and burn much cleaner which contaminates the oil with less fuel and soot.
Additionally, manufacturers are building engines to tighter tolerances, and specifying thinner oils for less pumping losses and shear/frictional losses to improve fuel efficiency. Finally, fuel has changed. The changes to LSD and ULSD have meant that there is less acid produced, and the old high-TBN oils are actually bad for the engines and unnecessary. Hard for many of us to keep up with the changes in oil specifications, but in most cases using a diesel oil in an older car with a newer oil spec/approval is adequate or better for running ULSD (which includes off-road fuel, also ULSD these days) provided it is CD rated and the proper viscosity.
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Gone to the dark side - Jeff |
#17
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Exchange TDT for 0w40
I took some of the TDT I stocked up on during that great sale into Walmart recently and just exchanged it for 0w40. I told them it did not meet Mercedes requirement for my car. They said "no problem".....now I have oil that meets MB requirements for 648 engine and I got a 25% bump in volume to boot
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-- Chris '95 E300, 216k miles, Silver Surfer '05 E320 CDI, 138k miles '07 S550 4matic, 69k miles Gone but not forgotten: '76 300D, 350k miles?, SOLD in 1995 '75 240D, 300k miles, SOLD in 1991 |
#18
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That UOA looks great. Im almost not believing how low Pb, Cu and Al are... Fe looks fine... Soot at 0.13% means there is so much retained dispersancy, that since the oil didnt go out of grade, you can go much longer. Id not condemn until out of grade, too low of TBN, or soot >1%. Wish we knew TBN...
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Current Diesels: 1981 240D (73K) 1982 300CD (169k) 1985 190D (169k) 1991 350SD (113k) 1991 350SD (206k) 1991 300D (228k) 1993 300SD (291k) 1993 300D 2.5T (338k) 1996 Dodge Ram CTD (442k) 1996 Dodge Ram CTD (265k) Past Diesels: 1983 300D (228K) 1985 300D (233K) |
#19
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Comments on TBN from OA tech: "TBN measures the reserve alkalinity left over in an oil after it has been in service. Used to be a real big deal with high sulfur fuels as they tended to leave the crankcase oil very acidic. TBN is still a factor but more so due to to nitric acid build up from the combustion process. It can sometimes be a factor in heavy duty trucks using EGR or SCR technology after high heat conditions. We still measure TBN, but rely more on TAN as it measures the actual acid content and TBN only measures remaining reserve in oil. Typically your oil is a 10.1 TBN and normally drops down to a 8 or 9 if the condition is extremely severe. I typically do not request that level of testing unless the drains are really extended such as 50,000 mile and above with commercial vehicles."
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14 E250 Bluetec 4Matic "Sinclair", Palladium Silver on Black, 154k miles 06 E320 CDI "Rutherford", Black on Tan, 172k mi, Stage 1 tune, tuned TCU 91 300D "Otis", Smoke Silver, 142k mi, wastegate conversion 19 Honda CR-V EX 61k mi Fourteen other MB's owned and sold 1961 Very Tolerant Wife |
#20
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Not sure I agree with that.
Yes, that oil should have good TBN retention, lots of buffering capacity... And yes, with lower sulfur fuels, the acid formation/tbn loss is slower. In low SAPS oils in gas engines (gasoline has higher sulfur content currently), we have seen TBN go to a condemnation level in ca. 5000 miles. Diesel has roughly half the sulfur of gasoline, and HDEOs have higher starting TBN, but Im not seeing a 50k mile equation here even if an MB sump is 2 gallons. For whatever reason, sometimes you have to write it in multiple places to remind them to do it, other wise they wont give you the testing you actually paid for...
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Current Diesels: 1981 240D (73K) 1982 300CD (169k) 1985 190D (169k) 1991 350SD (113k) 1991 350SD (206k) 1991 300D (228k) 1993 300SD (291k) 1993 300D 2.5T (338k) 1996 Dodge Ram CTD (442k) 1996 Dodge Ram CTD (265k) Past Diesels: 1983 300D (228K) 1985 300D (233K) |
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