Synthetic engine oil not being used..?

[Lazy2.5]

When I had my 2017 Mazda 6, I switched to 5W30 after the first year. Ran quieter and better after that. There's a few threads on the subject, and lots of opinions, but I swear by 5w30 versus 0w20.

Totally agree. My 2015 6 gets only 5w30.

I wouldn't mind going thicker in hot weather.

 

[Buzzman12]

Totally agree. My 2015 6 gets only 5w30.

I wouldn't mind going thicker in hot weather.

You could go 5W40, but I wouldn't go higher than that.
Keep the first value at 5 though, whatever you use. That's the viscosity when cold (W =winter). The second number is the viscosity when engine is warmed up.

 

[Lazy2.5]

You could go 5W40, but I wouldn't go higher than that.
Keep the first value at 5 though, whatever you use. That's the viscosity when cold (W =winter). The second number is the viscosity when engine is warmed up.

I agree.

I have tried 10w30, 10w40. It is unnecessarily thick, but worked fine for summer months. Not ideal for the winter though.

5w30, 5w40 is good.

 

[Boland01]

I believe where you live comes into play too. Down here in Houston we're typically mid 90's or higher al summer. Our 2023 CX5 Turbo recommends 5W30 all year round while the owner's manual on our 2025 CX70 Turbo S states 0W20. If you're in Mexico it's 5W30 too on the CX70.

This summer I'm contemplating using 5W30 in the CX70.

 

[Lazy2.5]

I believe where you live comes into play too. Down here in Houston we're typically mid 90's or higher al summer. Our 2023 CX5 Turbo recommends 5W30 all year round while the owner's manual on our 2025 CX70 Turbo S states 0W20. If you're in Mexico it's 5W30 too on the CX70.

This summer I'm contemplating using 5W30 in the CX70.

Use 5w30

 

[RobertJT]