Oil Changes . . . How often?

BenK wrote:
Any one compare the cost savings of extending oil changes vs an engine rebuild ?

Played around with 10K-20K mile changes when synthetics first came out
1 quart cost more than my hourly rate still in college

Plus, 'my' engines run better/stronger/etc with fresh oil

But, know I'm anal about these things....

One of the more interesting things is that oil analysis only run a limited set of tests, but cannot pick up things that is not specified that may matter.

Effect of biodiesel is one, where it can be picked up in dilution percentage, but the chemistry of a easily oxidizable and biologically active material that is home to microbes that produce metabolites and how it in turn interacts with oil and affect oil properties are really not known.

Just as when ethanol was first added in large quantities to gasoline, it leached all kinds of crud off the fuel tank that was use to straight gasoline, and in my case, it resulted in a trip to the dealer for warranty replacement of a burned plug / coil from the crud.

The cost of extended oil changes generally do not pay --- if you keep your vehicle past 100,000 miles.

You notice my brand new / rebuilt engine flush procedure?

Amazed to see how much particles are left in a "clean" new engine from the factory.


Interesting you should mention performance --- the biggest gain is in lubricity --- and being in grade.

Ford led the industry in switching to lighter oils (5w-20) because it was roughly 1-2pct better in fuel economy (easier to pump, hence both less wear and less friction with higher oil pressure.

http://www.machinerylubrication.com/Read/518/motor-oils

As oil ages, contaminates, and dilutes, friction steadily increases --- see above article.