Which engine oil is best for Yaris 3rd Gen?

[momaterials]

The car is still under warranty and usually I maintain my car in Toyota garage here in Algiers .they use the 15w40 on every oil change .in the manuel there are some explanation but I m not sure and I could not understand technical info ,that why I m looking for your advice lol
that s true the weather in Algeria is hotter than other European or american countries which involve special oil engine
the thing is that I doudt about Toyota agent using Total 15w40.I have heard and checked some websites that 5w30 is better ;improve fuel efficiency and car performance

[IllusionX]

Originally Posted by momaterials

The car is still under warranty and usually I maintain my car in Toyota garage here in Algiers .they use the 15w40 on every oil change .in the manuel there are some explanation but I m not sure and I could not understand technical info ,that why I m looking for your advice lol
that s true the weather in Algeria is hotter than other European or american countries which involve special oil engine
the thing is that I doudt about Toyota agent using Total 15w40.I have heard and checked some websites that 5w30 is better ;improve fuel efficiency and car performance

Well, you might not properly protect your engine with harsh temps like in Algeria if you go with 5w30. 5w30 is what is normally used in North America.

[bronsin]

Originally Posted by momaterials

The car is still under warranty and usually I maintain my car in Toyota garage here in Algiers .they use the 15w40 on every oil change .in the manuel there are some explanation but I m not sure and I could not understand technical info ,that why I m looking for your advice lol
that s true the weather in Algeria is hotter than other European or american countries which involve special oil engine
the thing is that I doudt about Toyota agent using Total 15w40.I have heard and checked some websites that 5w30 is better ;improve fuel efficiency and car performance

Ask them why they use 15-40. They may have a reason.

I doubt use the thicker oil will have an adverse impact on the engine. Offhand I would say it makes sense.