Your owner's manual will tell you what engine oil your car needs.
For NA, Mazda and Castrol are two of the recommended ones.

 

dont have the manual. its a recond car from japan and same was not found in the car

 

You can probably find it online, on the Mazda web site.

 

i wonder if its 0-20 or something similar

 

1.5 diesel? Google shows 5W 30

 

Go with what is in the manual...just don't buy cheap crap oil... synthetic is always nice. Besides that, do your oil changes as scheduled and don't worry about it.

 

Fill it with synthetic in a grade appropriate for your tropical climate. I suspect the manual may recommend 5W-30.

In northwest Texas, I fill my 2018 2.5I petrol engine with 5W-20 Pennzoil Platinum synthetic.

 

0W20 of whatever is on sale. If you live in a cold climate then you might want to get runniest oil in 0W20 from those youtube test.

 

The cap should list a weight for the oil, or look up a manual, I’m sure you can source a digital one. As for brands, mobil 1, royal purple synth, castrol, and Mazda/idemitsu. In my ranger I used castrol. In the Volvo I had, used royal purple. Important thing is to get the weight/visc right, and whether it needs full synth

 

go

google saying the below:

 

www.amsoil.com they have a finder of what works on your car.