0W30 oil is made to allow easier starting in cold weather. The first number (the 0) represents how well the oil flows when the engine is cold: the lower the number, the better it flows.
The second number represents how well the oil protects the engine when it's hot. The higher the number, the more resistant the oil is to thermal breakdown, so in normal driving, especially in warm climates with mild winters, using 0W30 instead of 10W30 won't make a whole lot of difference. It's mainly meant to offer benefits to those who drive in cold places (like Canada!)
I've used 0w30 in the winter here, and it does wonders. Car started up on COLD mornings with no problems at all, though I use 5W30 now in the winter and the car still starts reliably. I don't have a block heater, and apparently don't need one, either.
Tugger5000, when you say increased gas mileage, do you mean the car is using more gas, or you are getting better mileage, as in using less gas?
I noticed the same things when I switched to 0W30.
The oil has no difference what so ever in regards to what speed you can reach in what gear. You should be able to reach 50 MPH in 2nd using 15w-50 or 0w-20.
I would only reccomend 0-30 for people in extreme cold climates.(below zero temps) 10w-30 would be much better for people south of the mason dixon line, or who never seen sub 32 degree temps in winter.
<hr width=60% noshade size=1 align=left>quote from 4DoorGL: "Told you. Random is cool as hell in person, even if he is a dick on the net <img src=/images/forums/snitz/wink.gif width=15 height=15 border=0> (j/k)"
Leave it to Random to Needlessly complicate things.
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