Wow oil still look new at 13000 mile.

I have no way of proving this...
But I'm convinced that oil longevity is aided by the nature of the HSD system.

We have a vehicle that strives to keep the engine warmed up to lower emissions.
We have an eCVT transmission that tries to keep RPM's in an efficient range.
And the engine is an Atkinson cycle engine, designed to promote efficiency over power.
Not to add, we have a vehicle that actually turns off for periods and runs on full electric.

Combined my speculation is that with a Prius, our oil is put under less overall stress.

 

The dipstick can look a lot cleaner than the drained oil. This is after 6 months and 4876 km's, old vs new:

 

i wish it looked like that on the dipstick, so i could read it.

 

Give it a rest. He knows he let it go too long. People get busy. Life happens. It's not like he didn't feed his puppy dog.

 

^^^ That, plus the fact that he admitted that he simply does not care. His car his rules..

 

Vehicle maintenance is not the part that affects vehicle longevity the most. It's your driving habis that matter most.

A few years back I watched an Indy 500. Over 40% of the cars dropped out due to mechanical problems. See, it doesn't matter that they had the best titanium alloys known to mankind, and world-class engineers who hand-torqued every bolt with absolute precision... if you drive a vehicle hard enough, you can destroy it.

Your driving habits have FAR more to do with oil and vehicle longevity than anything else.

Toyota recommends a 5,000 mile oil change interval if you drive "under harsh conditions," which really means, "If you drive like a racecar driver". Although, I suppose it applies to really harsh environments, like if you park your car outside in the middle of winter in Alaska.

 

Well, at least I learned the recommended oil change interval! That's why I love this site.

 

there is some evidence (granted, limited) to the contrary: interesting oil study by Infineum | PriusChat