Qwikrex

Will I notice any loss in performance switching frow 5W30 Castrol to 10W30 Castrol????

bretx0r

no

EKB18BPR3

u wont notice cu its a tiny difference...but one's a ticker solution so thereotically ur engine will work slower using thicker oil...but im just talking out of my *** at 6 in 5 in the mornng so dont listen to me

hondafrk

wont make any difference. If you started using straight 40weight then you may notice a small difference.

shawnhayes

Come on guys. Let's remember how the rating works. 5W-30, acts like 5 weight cold, 30 weight hot. 10W-30, 10 weight cold, 30 weight hot.

Summary: No difference hot, five weight difference cold. How much difference is that? Not much, but there is some, but it will last for like two minutes during warm up, and no moron goes all out in the first two minutes after the car is on.

Shawn

.paul

or so we hope....

g_man80

One question (maybe because I drank too much last night, but): wouldn't the 5 weight be thinner than 30 weight (talking about 5w-30), so the oil would act like 30 weight cold and 5 weight hot? Maybe I have it backwards, but I thought the higher the weight, the thicker the oil? Just looking for some clarity. Thanks
G, (whose a little hung over at work)

Qwikrex

So then when heated up the 10W30 will act the same as 5W30?

NeedMOPower

ya 5 weight is thinner than 30 weight.. 5 weight is used for colder start up temperatures i.e. Cold weather where a thinner oil is need to before the engine heats up. Where as in warmer temperatures you would want a 10 weight.

The main advantage to using a 10W30 is that the operation window is larger it can handle higher temperatures when running. Where a 5W30 cannot handle quite as high a temp. Unless you are in the winter months in Canada you should only need to use a 10W30 motor oil.

And to clerify just like specified above it would be 10 weight cold 30 weight hot.

g_man80

But what I don't understand is that the oil acts like 5 weight cold and then 30 weight once the engine is at it's running temp. How does the oil get thicker once hot? I would think 5w-30 and 10w-30 would be the same weight cold (30w), but the 5w gets thinner when hot and the 10w would remain slightly thicker (for hot weather).

NeedMOPower

read the words on the paper not between the lines.....when cold a 5W oil is thinnner...for start up at cold temperature... a 10W oil is thicker so that if it is really hot out the oil will not be to thin. That is what matter the second part i.e. 30,40,50 is the operation thickness of the oil. Just remember that higher second numbers are for higher operational temperatures. That is all you really need to know. If your car is only for autocross allways pounding it on a race track and not operating at cold temp you want to use a 10W 50 better for higher engine temperatures.... Just remember this if you are in a cold climate i.e. winter when it is cold enough for snow to be on the ground use a 5W motor oil if the temperature is warmer use a 10W that is all that is needed to know right now.....some of this is not so easy to explain typing ... so that is as far as am going to go


good luck

g_man80

Yeah, I guess I was just reading too much into it. I get it now. It's really not worth loosing sleep over, haha.

Anyway, for the original question that was posted; you won't see any difference switching between such similar weight oils. Just like what was typed earlier.
Thanks,
G

NeedMOPower

no difference....check what weather you will be using it in then decide colder 5W30 warmer 10W30

enjoy

shawnhayes

Oh my GOD, apparently I have to discuss the behavior of multiweight oil.

Ok, multiweight oil is what is called a "non-Newtonian fluid". In other words, viscosity INCREASES as temperature goes up (but this only applies for a limited range of temperatures - and automotive chemists aim for the -35 to 500 degree farhenheit range).

It takes tons and tons of egghead chemistry (that I used to know) to pull this trick, and is one of the major reasons you need to change your oil regularly (because the viscosity index improvers wear out over time).

So, at low temperatures, a 5W-30 oil has the same viscosity as a 5 weight straight oil at that temperature, and at engine operating temperature it has the same viscosity as a 30 weight straight oil.

Straight?

Shawn

Ricey McRicerton

hey shawnhaynes....you, my friend, are a genius