I use 5w-30 a well, but I'm curious as to why you say it's better for engine. I assumed it was climate dependent. And seeing Alaska on your avatar would make me think you'd actually prefer 0w-30. Insight?
In Illinois now but used 5W-30 in every climate in US ranking from 105F to -40F.
Lots of technical info on why I choose to run 5W-30. There are myths about tighter bearing clearances in the 3UR which are incorrect seeing as the 1UZ had sighted main bearing clearances than the 3UR which is 25 years newer. The GSF V8 which is a modified 3UR calls for 5W-30.
Moreover, ROTW (rest of the world) 3UR Land Cruisers have recommended oil weights from 5W-30 all the way to 20W-50. These countries do not have EPAs.
Lastly, the EPA requires the manufacturer to mandate the oil used during efficiency testing. Toyota used 0W-20 because of its lower flowing resistance in an attempt to squeak out every last bit of gains possible. Note how it says in the manual heavier weight oils may be used if excessive speed/towing is the norm. What’s excessive speed in a Land Cruiser?
Bottom line, manufacturers are under ridiculous oversight from our lovely big government. 10,000 mile OCI’s, “lifetime” fluids, and low viscosity oils are all attempts by manufacturers to lower their environmental impact for investor relations and public imaging purposes.
I have noticed no material impact to MPG (I drive a cruiser so who cares really), and a quieter valvetrain in both my brand new 2020 Cruiser and 14 LX. I swapped the LX over at 95k and the mysterious consumption between changes is now gone. The light weight oil was vaporizing in the combustion chamber. I swapped my Cruise over at 2,500 miles.
I use regular M1 synthetic 5W-30 as it’s shear strength is significantly higher than its EP counterpart.