On 12/3/2019 11:18 PM, Ralph Mowery wrote:
In article , says...

The right way would be to do an oil analysis every X miles. Driving
conditions vary so much we'd all be on different schedules for changes.

We used to do that with hydraulic units on the machines. Cheaper to pay
for an analysis than replace 55 gallons of oil that is still good.



for big machines and maybe a fleet of vehicles, but for a single car, it
would probably cost way more to test it than just change it and the
filter.

You can get a test for about $25. Problem is, it takes a couple of days
to get results. Draw a sample, mail it to a lab. That would be
difficult to schedule at a dealer, impossible for a Jiffy Lube to stay
in business. I have no idea of the investment or training to do it on
the spot.