Is there a difference using 5w vs. 10w grade oil? I was just gonna change my oil, and I have 5 qts. of Castrol Syntec 10w-30 here. I was at www.castrolusa.com and they seem to recommend using 5w-30 for better oil flow at startup in cold weather... I am in WI so does anyone have any advice? Anyone think i should return it and get the 5w?




[Modified by sivik2nr, 9:08 AM 11/12/2002]

 

Its not gonna make that much of a difference...but they are right about using 5w-30 in the winter time...if you feel its going to be a difference return it and get the 10w-30..

 

I'm a texas local, and I've always used 10w-30 in everything becuase of the heat we get. I spent some time in the midwest during winter and I'd think 5w-30 or 0w-30 would be a good idea.

Most people will tell you the most important thing about oil is to worry more about how often you change your oil and less about what kind of oil you run.

 

Either oil will be fine. In very extreme temperatures, say for instance 0-20 below, you would be safer using the 5w-30 because of that weight oil's ability to flow better in the extreme cold, but for your normal temperatures, both will be ok.

 

10w is thin and 5w is thicker. I live in Colorado and I use 5w year round. My brother used 10w for a while and he was experiencing oil burn off, probably due to the thin 10w. He then switch to 5w and problem solve, no oil burn off.

 

Just to clarify some things for you. 5w-30 is thinner than 10w-30. When oil companies do their viscocity ratings, a higher number is thicker and flows less feeely, while a low number, like 5w30, is thinner and flows more freely.

Here's everything that you could possibly ever want to know about motor oils:

http://www.howstuffworks.com/framed....02/8/motor_oil/

 

You got the numbers backwards, the higher the number the thicker the oil.

 

5W30 is thinner at cold startup than 10W30 but when it warms up, 5W30 and 10W30 are the same.