I just got a 2010 corolla and am gonna do an oil change. I think I'm gonna use 5W-20 since its almost summer and warm out. But then when winter(canadian winter) comes can i use 0w-20, or is it bad to swap back and forth.
It won't be an advantage to your engine if your manufacturer suggests you use 5w-30.
The consensus is and correct me if I am wrong 0W-20 is thinner oil at low temperatures for engines with ISG where the engines shut off when the car is not moving. At lower temperatures thicker oil makes the engine more difficult to re-start. The overriding factor is warranty. You don't want to introduce an excuse for the dealer to charge for an otherwise free repair. As far as operating with thinner oil I would think long and hard before using any thing contrary to the manufacturers recommendation.
What does your owner’s manual say?
It won't be an advantage to your engine if your manufacturer suggests you use 5w-20.
http://www.tcorolla.net/lubrication_system-394.html
Recommended viscosity: SAE 0W-20
SAE 0W-20 is the best choice for good fuel economy and good starting in cold weather. If SAE 0W-20 is not available, SAE 5W-20 oil may be used. However, it must be replaced with SAE 0W- 20 at the next oil change.
Is there actual scientific proof that your car would be better off using 0w-20? I’ve always heard Scotty, and other mechanics, say to use the manufacturers recommended oil. I would stick to that.
