Frozenr6

Sorry I know that I am a noob, but there are some serious myths here about oil and lubrication. As an example I have run regular dino oil in engines tha run at 85% duty cycle all day and night for the equivqlent of 40,000Km's. The reason to change oil every 4-5000 miles is that from a cost benefit perspective it is cheaper than taking regular samples to extend the interval.

Using a high quality filter we all under normal conditions could likely run the oil itself 10's of thousands of mile by only changing the filter, but that would require detailed understanding of the oil properties at any given time, hence cheaper just to chnage the oil.

Sustained viscosity breakdown is typically not caused by heat, that is genrally isolated to the event, but rather it is caused by an external contaminant be it coolant, moisture or by-products of combustion leaking past the rings(normal).

The most significant reason to have your vehicle serviced is to have the filter changed, at all costs the filter must not be allowed to become sufficiently plugged as to go into by-pass. The damage done with no filtration is near instant and is certainly irreversable.

When do you want to change your oil is upto you, synthetic oil changes should not be significantly longer than dino oils, because at the end of the day they have a finite capacity to carry contaminants and I have not seen a study that says they are measurable different.

I could probably ramble all day but will stop there.