7tisix

I have a 2015 IS350 F-Sport in Baton Rouge, Louisiana. The temperature rarely falls below freezing in winter and in the summer the temperature will get up to 100 degrees very often. I know I am supposed to use 0W20, but I use 5W30 anyway. Will there be any negative consequences that may arise if I keep using 5w30? I use Castrol Edge because when using Mobile One on my old 2IS I would hear a little more valve noise. I have searched the 3IS forums, but I have not found a thread that specifically addresses this common situation.

E46CT

That's hard to say 100% certain without testing of the actual engine, but i doubt 5W-30 would cause any problems. plenty of high performance cars use higher viscosity oil. and for example on the Camaro (ZL1 i think) they recommend switching to heavy oil for track use then switching back for the street. just as an example of how the same engine can be OK'd for two wildly different viscosities.

Also it is quite possible for a 5W-30 to have an actual tested viscosity that's thinner than a labeled 0W-20. The label isn't the end all be all but is just a general indicator of what range the oil falls in.

People tend to forget that oils often test different than what they're marketed as. So the takeaway is there's always going to be small differences and the car won't really know different.

Your safest bet is to always use what the manufacturer recommends, but if you go a grade or two thicker, particularly in a hot climate, you should be fine.