Winter oil and summer oil

[Clogged_Toilet]

Hola Amigos,

I was wondering if there would be any ill effects of changing the oil weight during the seasons. I put 5w30 during the summer and then when it get cold here I was thinking of putting 5w20. Would this hurt my engine in any way?

[invasion08]

Do not use 5w20. In oil grading, "W" stands for "winter" and the first number given is the winter viscosity, or ability to flow, of the oil. The second number refers to the hot temperature viscosity of the oil.

I use 5w30 all year round here in NJ.

[Mhannis]

while i agree that 5w30 is fine to be run year round. the W standing for winter..is total bullshit. it doesnt stand for anything at all. its a random letter chosen to differentiate between what would be the low temperature rating and the high temperature rating. low temp rated as 0w, 5w, 10w. with high temp rating just being the number, 20, 30, 40, 50. etc.

the reason people call the W either "winter" or "weight" is because in most peoples heads, everything has to stand for something.

its just a W. interchangeable with any other letter or character in the english language...and others too im sure. may as well be 5#30 and it would mean the same thing.

invasion. thats not a personal pick on you at all. please dont take it that way. i just see that all the time and it drives me nuts because i know better but always see that people keeping calling it something its not. im just a W nazi i guess.

[invasion08]

Looks like you hate the letter "W".

[D189379]

I've ran 5W20 last winter and it was fine. I did a UOA on it as well and it held up great.

I did mostly short trips last year, so the 5w20 was probably still too thick.

[invasion08]

In colder weather a thinner oil than 5w30 is 0w30.

[Mhannis]

^ this. going to 5w20 just made your heat range lower. no change in cold weather performance.

[upflying]

Originally Posted by Mhannis

while i agree that 5w30 is fine to be run year round. the W standing for winter..is total bullshit. it doesnt stand for anything at all. its a random letter chosen to differentiate between what would be the low temperature rating and the high temperature rating. low temp rated as 0w, 5w, 10w. with high temp rating just being the number, 20, 30, 40, 50. etc.

the reason people call the W either "winter" or "weight" is because in most peoples heads, everything has to stand for something.

its just a W. interchangeable with any other letter or character in the english language...and others too im sure. may as well be 5#30 and it would mean the same thing.

invasion. thats not a personal pick on you at all. please dont take it that way. i just see that all the time and it drives me nuts because i know better but always see that people keeping calling it something its not. im just a W nazi i guess.

I dunno, Amsoil seems to think "W" stands for winter.
Motor Oil Viscosity Grades Explained in Layman's Terms

[Mhannis]

i believe thats just going with common nomenclature of the time, especially since its a "layman's terms"

when the standard was created..it had no true designation. winter/weight were just two that caught on for the "layman's terminology".

[D189379]

Originally Posted by Mhannis

^ this. going to 5w20 just made your heat range lower. no change in cold weather performance.

Not totally true. 5W20 should be thinner through it's entire viscosity range once it starts warming. So unless you start your car at -40F every day, the 20 weight will flow faster at any warmer temperature.