My focus uses 5w20. I know 5w20 protects the engine with no problems but was wondering about summer months. I live in chicago and it gets hot. Upper 90's and humid all last summer. Do you go up to maybe a 5w30 in the summer? It's just a daily driver.
Yes. Changing visc for seasons seems antiquated, but I think it is smart. My OT does not even get to +200f in winter, why use a 15cSt oil? Summer sees above +220f. I take care of visc/temp issues by blending. For most, 5w-30 winter/10w-40 summer seems good. If I had a 5w-20-mobile, I'd do it as you said...Motorcraft anyone?
Yep. You can blend a 50/50 mix of 5-20, and 5-30 for summer and you will be fine. But even if you don't, you are really OK with the 5-20. There have been several UOA to judge the 5-20's from. Havoline would be a good choice, as well as the factory MC from WalMart.
I do that with my 01 Supercrew, 5.4l engine. Use 5 quarts of M1 10W-30 and 1 quart of 15W-50 in the summer months down here. Winter, switch to M1 5W-30. We own two Accords, 02 and 06 V6 models, on those, I just use 5W-30 M1 year round. UOA's have shown that Honda is pretty easy on oil while the big ol' V8 is a little more harder.