On 03/26/2021 10:32 AM, mike wrote:
I don't disagree on having your oil sent out after the fact for testing.

Different situation but when I was driving the standard was 12,000 miles
or about once a month. At 10 gallons or Rotella and two or three
filters, that adds up.

When the older trucks were being replaced with Volvo Whites with the
Detroit 60 engines, the shop foreman started a testing protocol.The
tests showed no significant degradation at 20,000 miles but that became
the new standard. When I asked him his reply was the oil had to be
changed sometime and 20,000 seemed like a reasonable target.

The Detroit 60's were game changers. A lot of them were hitting a
million miles without an in-frame rebuild. Previously most big diesels
were tired at about 700,000.