I’d love to have that done too for a definitive answer. If someone had it done with normal driving conditions in a good mix of city and highway miles that would be comparable results for most drivers.
Any ideas on where you send a sample for analysis and what the cost is?
I’ve always been on the fence with the 10k changes too. Honestly I’ve never let one go over 5k, even with synthetic. I was going to attempt it with the 0w-20 on the 17 Tacoma but I’m at about 4,400 miles now and it’s starting to bother me! Will probably have to go ahead and do the 5k change. I can definitely see the importance if you are towing much or doing a significant amount of hard driving.
Devil’s Advocate to that is these engines were tested under all conditions with the recommended oil weight by the manufacturer so their guidelines should be pretty safe to follow. If nothing else Toyota is losing money with 10k changes with less service visits.