Hey there, i was reading the user manual on my 2009 Mazda 3 i Sport with 198k miles standard transmission, and it said to use 5w-20, but if a turbocharger is installed to instead use 5w-30.
My questions are, why do you have to use different engine oil whether it has a turbocharger or not, and if I were to install a turbocharger in the future, would i have to switch over to 5w-30?
The 5w-30 is thicker when it is hot. More likely to stick to high speed spinning bearings in your turbo that gets hotter then the exhaust manifold.
Exactly what @cjbman said. I have a 2008 Mazda3 GT, and the owner's manual does include information for the turbocharged version of the Mazda3 (Mazdaspeed3) as well. Just ignore the turbocharger stuff in the manual as they are different engines.
