Yaris Oil Change DIY

[sbergman27]

Originally Posted by PhilD424

Damn 5W20? Thats wayyy to thin. Even so with 5W30. I personally wouldn't use anything less then 10W30, atleast for the kind of driving we do in NYC.

5w30 is considerably thicker at 0F than it is at 200F. Just not by as much as a straight weight oil. Why do you think that it needs to be *even thicker* when cold, but don't seem concerned about 5w30 at normal operating temperature. In practice, the lower the first number the better. It's the second number that is really significant. Personally, I don't see the point in 10w30. It just takes longer to flow and makes the car harder to start in cold weather.

At any rate, Toyota says 5w30. Some engines, Yaris' included, use the engine oil as hydraulic fluid to do certain things. (Yaris' vvt-i engine uses it to control the valve timing.) So messing around with non-spec viscosities *can* have unintended consequences.

Use what the filler cap recommends.