Engine oil VALVOLINE or PENNZOIL

That's what I run. It supposedly runs lighter than the specified 40. It's LL-01 approved. I change it every 8000km/5000miles.

Valvoline vr1 20w50 I'm convinced they basically make it for rotary's to begin with.

The best performing oil for cold starts is probably Pennzoil platinum full synthetic if your particular prius uses 0w-20. It is made from syn gas, and is particularly thin.

For comparison, i got 6,000 miles out of Pennzoil platinum vs royal purple, with which i would get 5,000 miles prior to the oil changing color and about a 1 to 2 percent dip in fuel economy. Regardless of the wear additives, Pennzoil platinum lasts longer, again likely due to the cold start performance and the way the hybrid drivetrain works.

Haven’t heard anything like that about Mobil 1, but I personally use Pennzoil Ultra Platinum 5w30. It’s performed spectacularly for me.

Penzoil Ultra Platinum will be on a entire different level. Stuff is amazing.

I've been using the valvoline personally and like it better than the pennzoil platinum.

Penzoil platinum held up nicely. A hair thinner and less active additive than Valvoline but wear looks great.

Used this for years in my 4 strokes. Quality oil.

I run valvoline in everything I own wether it’s diesel or gas. I used to use Rotella for my truck and pensoil for everything else, but valvoline seems to make it all run better and smoother

I run Valvoline blue and love it. Run it in my IDI and my 454 Burb