Switched to 5W-30 from 0W-20

[N7turbo]

Note that the Skyactiv 2.5L is not specified to use 40 weight oil.

https://www.mazdausa.com/static/manuals/2023/cx-5/contents/07030402.html

Only up to 30 weight.

 

[Kedis82ZE8]

This is always a hard, non-negotiable requirement. The rest you are correct about.

Sorry.. just hasn’t been my experience in nearly 40 years of driving.. never chased latest spec and always had great reliability on my engines. Aggressive service schedules served me well or I just made reliable choices in vehicles with greater tolerances to oil variances

 

[N7turbo]

Considering the spec includes improved engine cleanliness and protection from low-speed preignition (for example by reducing the calcium in the formula) it is important to just use the latest oil. In fact, there is no reason to ever use old spec oil. There is simply no advantage.