On 12/3/2019 7:45 PM, Ralph Mowery wrote:
In article ,
says...


On the other hand, BMW pushed oil change intervals to 15K for a few years,
before backing down to 10K. You would think there would be an incentive
for them to make it as high as possible, since their new cars get free
oil changes for 50K miles. That's 5 changes vs 3 that BMW has to pay for.
So I figured they must have seen something negative from 15K, but then
who knows.




The oil is probably good for that, but maybe gas contaminates the oil.
Just a few drope each time the engine is stopped and started. If ran
off propane or such, the gas contmination would not be a problem.


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.