PHEV specific topic: oil change based on time ONLY

Ah, I can see the dilemma in that. I have that concern with the front differential in my Tundra....it only circulates the fluid around when I have the truck engaged in 4x4 low or high. Since the actuator is electronic, not engaging the 4x4 often enough can result in a truck driver wanting to engage, and the actuator isn't able to work. (Happens a lot in the 4x4....I have a co-worker with an older Tundra 4x4 and was a victim of it....spent a lot of time fixing it.) The "fix" I've learned from the Car Care Nut (Ahmed) and others, is just to turn on my 4 Wheel High once a month for a few miles, which I do. (I just find a long, straight road and turn it on...don't want to be turning corners with a 4x4 on hard pavement.)
I do remember Ahmed saying that if you don't drive very much, then you shouldn't get a Prime Toyota or even a Hybrid as the ICE engine really does need to be running fairly often to keep it happy.....but where's the sweet spot? Once a week or so?

 

Individuals' life experiences and "you can't trust your lying eyes" (Eagles song) - oil color change can mean a lot of things. The only real in- controversial test is an oil analysis and I'm too cheap to do that - since it's more expensive than a filter. Otherwise good thinking. Smell will also allow you to see if your allowing the engine to run long enough to evaporate gas and moisture deposits out of your ICE.
I use to drive a diesel VW; that oil would turn black in less than 25 miles; whereas my Prime will go about a month and a half before the oil turns slightly amber enough for me to read the dipstick without using a clean tissue to determine it's level.

YMMV

 

apologies for being pedantic, but: you’re essentially saying “internal combustion engine engine”.

just saying “engine” would suffice?

 

Me too! I put in Delvac1 (Mobil1 for diesel) every 10,000 miles, as recommended by VW. It was still running like new at 225k when I sold it.

 

Even before synthetics became the norm, the point of the oil change wasn't because the oil went bad. It was because additives get used up. Some of those have consumption rates that line up with engine use. Others could get used up faster depending on the climate. The acid neutralizers can be consumed faster in humid climates. It's water getting into the oil than forms the acids.

These aren't things that can be eyeballed.

Was the diesel pre-ULSD? Sulfur is a culprit in coloring oil black. With the shift to even lower levels of sulfur in gasoline for Teir 3 emissions, motor oil is going to last longer.

 

when i traded my 2012 PHEV, it had 87,000 miles. only 25,000 on the engine, and that with a 13 mile ev range.