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Originally Posted by DougR
The following sources indicate TBN is not accurately measured and TBN guidelines are changing. What TBN guideline do you recommend?
Blackstone uses ASTM D4739 to measure TBN. This test method can yield a result as much as 2 mgKOH/g lower than a more accurate test. See Used Engine Oil Analysis TBN vs TAN | Chevron Lubricants (US)
Understanding Total Base Number in today’s HD engine oils states "A quick and easy rule of thumb for most oil analysis laboratories and many fleet maintenance managers is to drain the oil when the TBN reaches 1/3 of its starting value or 3.0 mg KOH/g, whichever comes first. Detroit recently released its 2018 Service Bulletin (DDC-SVC-BRO-0001) in which it has removed TBN limits entirely from the used-oil analysis parameters. Discussions with other key engine builders has revealed that they have noticed that used-oil TBN values are often very low – sometimes below 1.0 mg KOH/g – yet without any additional indications of adverse oil condition. We expect other engine builders in time to follow Detroit’s lead and either update or eliminate their TBN guidelines." |
Thanks for that, good interesting info.
My view is that oil analysis and when to change oil is relevant to heavy equipment, fleets, and industrial machine use where there are lots of vehicles and lots of oil to change. In those cases it makes sense to analyze oil regularly to get the maximum miles or hours of service and change if at the optimum time to balance machinery life and cost.
For my 6.6 quart oil capacity 4Runner I don’t analyze or overthink the oil chemistry. Just use a top notch oil and filter and change them regularly, about every 5,000 to 7,000 miles. If I do a lot of severe driving, change it sooner.
