Is it correct that multi-viscosity oil is to compensate for varying starting temperatures, that the oil is formulated to change as the engine temp increases? I.e. 5W-30 and 20W-30 end up at the same viscosity at operating temp?
Assuming this is correct, why isn't all motor oil simply formulated for the coldest possible weather?
And why 30, 40, 50 as the second number?
The summer (and the winter numbers, for that matter) are decided by the engine designer and the clearances, design oil flow rates, and pump design. Also, sometimes the designer specifies higher number for "extreme" conditions (towing heavy trailer through high desert, etc). So there needs to be a range of viscosities on the market.
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Not ...ALL.......engine tolerances are the same.
jest fer one example of why.
Now.....jest to start a good arguement thread.....lets add......that its possible.....SOME manufacturers care more about advertised fuel consumption than they do the working longevity of their engines, as long as they know the engines will last well past the warranty period. (jest food fer thought)
Anywhoooooo.......because yer inept at the "google is yer friend" concept.......take a gander at dis.
~:~ MarshMonster ~takes a toke.......mmmmm......good stuff~ ~:~
Anywhoooooo, and take this in the spirit it's meant, kindly go f*ck yourself, repeatedly, with a rusty pipe wrench.
I figured I'd ask those in here to see what alternate takes I might get on it.
People like you who preface their commentary with an insult when no one was insulting you are typically stubby-dicked pissants who wouldn't repeat such mano a mano without the cops and a lawyer on speed dial. You fancy yourself brilliant? Who cares.
Why is there more than one type?
1) Marketing. 2) We don't all drive the same kind of car with the same type of engine. 3) Backwards compatibility with old cars (see #2) 4) Profit. (See #1)In theory, a 10W30 and 5W30 should flow the same when hot, and a 10W40 and 10W30 should flow the same when cold, but they don't because they're not the same product. (See #2 and #3.)
It's the same reasons why we don't just have good old green antifreeze anymore.
And yes, it's kind of annoying. I own more than one car, and have to "stock" multiple types of oil and coolant.
Ray
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