I'm now putting 20w50 in my Prius. Arrrrh!

Is "viscosity increase" practically achieved by going to higher oil weight, say going from 5W30 to something like 10W40, in the same brand/spec?

 

What are your stakes when you use a heavier oil like the 20W-50 in places like the middle east, and Africa, where you have temperatures climbing to 40-+ degree Celsius?

In Nigeria particular, we don't have issues of snow and winter blablabla, so there isn't a problem of hard start issues during cold.

 

Look up "coincidence" in the dictionary. Or do a google search.

Except for the engine running a little less, the HV battery has NOTHING to do with oil consumption.

 

I wouldn’t say that it has nothing to do with it besides running a little less.

If you have a hybrid battery that has low capacity engine will be running harder and at higher rpm since all the power has to come from the engine after the hybrid battery is “empty”.

But lot bigger effect is that if there’s downhill where the extra energy has to be wasted by spinning the engine in B after the hybrid battery is full. All that time there’s a high vacuum in the engine that will try to suck in oil. With the new hybrid battery there might not even be a need for wasting the energy by spinning the engine.

Of course it can still be just a coincidence.

 

That is the most common way, yes. But pure Dino v semi-synth v full-synth in the same weight, can all be different viscosities when cold. The difference is not normally large, but measurable. Oil also "thickens" as it wears out (ages), so that is another factor to keep in mind.

 

If the old HV pack was bad, a new one would certainly not only cause the engine to run less (total average minutes per day or mile), but also when it does run it would not be at *as high* of a load. Both of these can dramatically affect oil consumption, because engine revolutions per vehicle miles and load are completely unrelated to actual distance traveled in a Toyota hybrid.

Basically, if you reduce the on-time each week and run the engine at 2/3 of the average load it had before (due to now having a good HV pack), lower oil consumption would be a logical result.