No 10 W 30 oil at Walmart.

72bluNblu said
Backwards sir.

Oil thins as it heats up. For a 5-30w you get the equivalent of 30w when cold, but all the way down to 5w when hot.

Nope not backwards. Its all about maintaining its viscosity, like stated below, it will maintain its 30 weight flow rating at 100*C, it will not thin down below that. But upon startup in colder temps, it will flow like a 5 weight to provide quicker oil flow. Ive attached one page of a very informative article I read years ago explaining it, the second paragraph is what you want to concentrate on.
It can be very confusing, thats why I had downloaded and printed off that article. Lots of additives and chemical properties involved that I know nothing about...haha

Bewy said
5W/30 oil means that at 0*C, the viscosity is equivalent to a SAE 5 oil. At 100*C, the viscosity is equivalent to a SAE 30 oil.

I think I may be guilty of not explaining it good enough, when I mentioned cold startup, since I live in Canada, I was thinking about wintertime when its very cold out. Thanks for adding that clarification.