quick question about oil

Its getting hot pretty soon and i was just looking at auto zone i usually use castrol synthetic blend. Then i saw they had the 10 w 40 and it said even better protection. So would 10 w40 be alright too use or would it be too thick and i should just do 10 w30 cause the 10 w30 bottle didnt say now even better protection. so i was just wondering if 10 w40 is ok.

I was just wondering because its the same brand castrol syntec same price only 1 is 10 w30 and the other one is 10 w40 bottles look exacly the same but the 10 w40 one says "Now even better protection" just wondering thanks.

try to stick with mobile 1 synthetic LOL. I just go walmart and bought 5q, thinking changing oil tonight , but out side rain like **** now . I guess i had to change tomorrow.

Don't be changing oils... engines don't like it too much... especially if you go from regular to synthetic...i'd say to stick with the same you always use... at the most that i'd ever done was like a 10w30 in the summer and 5w30 in the winter...

Actually yeah im doing Castol part synthetic motor oil. Besides if i was going to do full synthetic id still stick with castrol i guess i just like it better then all those mobile 1 oils.

Mobile 1 isnt better then castrol is it. And should i not try that 5 w 40?
i always idle my car up to normal operating temp before i drive it so i should be cool right since i drive my car daily it would help out with those hot summer 100+ dagree days right?

Thick oil is not a problem in summer, thin oil is. In the cold weather, thick oil can be a problem, and blow 0 degrees most poeple switch to a 5w oil. The full synthetics are like water anyway, not sure if the blends are the same.