I've been doing a lot of driving over the past few weeks, so I decided to get an oil change today and purchase new windshield wipers. Since the manager of the local Tire Kingdom was very nice to me last time I was there, I decided to go there instead of the dealership. Actually, the Toyota dealership is also very helpful, but they're more expensive and I don't need my tires rotated or any of the extras this time that might justify charging $34.95 plus shop fees & tax for an oil change.
When I got home I noticed Tire Kingdom used 6 quarts of 10W30 and I know the dealer uses 5W30. I realize that the 5W30 is thinner and is recommended for colder climates and that 10W30 is pretty standard. But I've also read online that using the high viscosity oil could result in "sludge" building in the engine. I've been on sites like Cars.com and others have asked the same question about which oil to use. Most answers said to use 10W30 in a mild climate.
I've learned the hard way that, when in doubt, read the Owner's Manual which specifically says to use 5W30 in all climates and says that 10W30 will result in poorer gas mileage. It also says that if it's necessary to use 10W30 because 5W30 is not available, to change to 5W30 next time the oil is changed. Mobil1 is what the dealer used.
This really concerns me. Isn't Mobil1 synthetic? Will this change to the other oil void the warrantee? Would you go back to Tire Kingdom? I guess using it only this once shouldn't have any damaging effects, but I'm wondering if they used the 10W30 because it was cheaper. The receipt says "bulk oil" and I'm not sure what that means exactly, except they buy an awful lot of it!
Okay - just read more information on the recommended oil (which is still 5W30) but there are several people who say that in very hot weather 10W30 is actually better because it won't break down and provides better lubrication. Except for Death Valley and Phoenix, I doubt if there could be many places hotter than Southwest Florida!