Engine Oil Burning?

In general, I agree with your KISS approach to oil changes -- no need to make it complicated. But in the case of the Gen-3 Prius, it's documented by Toyota in this TSB that this engine has the potential to develop an oil consumption problem that's not related to traditional wear. The cause is not worn rings and valve stems that would be the common cause in other engines, but rather coked oil deposits at the oil containment rings caused by insuffient draining through the piston valleys. The fix is simply new, revised pistons and rings. A complete rebuild is not necessary because the cylinder walls have not been damaged, and the valve guide seals are fine.

 

Thanks for link to the TSB as it was fascinating reading. I have never worked with a 3-part oil control ring assembly—the oil ring expander surface thing that pushes out the top and bottom oil control rings was new to me.