I want to see if they call for the same thing there that they do here. Here they ask for 5w20 which is really thin and IMO is just for fuel economy reasons. If in Autstralia they call for 5w30 or 10w30 I have proof it's safe to use in my engine.
According to the user manual and depending on temperature they indicate the following oils SAE viscosity ratings. 20w-20, 10w-40, 10w-50, 20w-40, 15w-40, 20w-50, 15w-50, 5w-20, 5w-30. Seems that 5w-20 and 5w-30 will cover from -20F to +100F (-30C to +40C).
It states in the manual "Engine oil viscosity, or thickness, has an effect on fuel economy and cold weather operation (starting and oil flow). Low viscosity engine oils can provide improved fuel economy and cold weather performance. But high temperature weather conditions require a higher viscosity engine oils for satisfactory lubrication."
looks like you own the hatch SP23, therefore the oil weight should be equal to the weight of the car. I recommend 1,251 kilograms of oil is added to your vehicle. This will give it a nice 1:1 ratio. Your engine won't hold all this oil so you'll need to make some room for it in the passenger compartment.
Alternately just leave it for your mazda service mechanics at your next service.
A forum community dedicated to Mazda 3 and all Mazda vehicle owners and enthusiasts. Come join the discussion about MazdaSpeed performance, modifications, classifieds, troubleshooting, maintenance, and more!