Mixing oils in my 2010 Toyota Corolla

Changing my car oil & have 2 1/2 gal of oil 1 Castro & 1 pennzoil can I mix them in my motor till next oil change.
Thanks Mo.

Sure, no problem, as long as they both are the correct oil for the engine.

If you’re a quart low of 5w30, assuming you’re capacity is a hair more then 4 quarts (like my 06 Corolla), even if you added a quart of 10w30, you would likely be creating 6.25w30. During warmer weather, it’s my understanding, that using a thicker while cool lubricant, doesn’t generally create an problems. I believe it’s a good rule of thumb to always use the same lubricant IF YOU CAN.

If both oils are the viscosity recommended by Toyota for your engine, they can be mixed and used.

If not, the different viscosity’s when mixed may have a negative effect on the variable valve timing of the engine.


For emergency purposes, yes you can as long as they have the same rating and viscosity.