One thing I can pretty much guarantee: the guy who changes his oil frequently will more than likely enjoy long engine life (barring any lemons or factory defects).
I think i said that. Synthetic does perform better in cold weather and extreme heat and tends to last longer. These are factors you can actually test in a lab. From a chemistry point of view most synthetic molecules are more stable then the ones found in conventional oil. I would think this would lead the average person to the conclusion that it will give you better protection, even if its marginal in some cases.
Pleas don't get me wrong, I'm not saying conventional oil doesn't work, because clearly it does. Just most of the research I have done says synthetic out performs conventional oil.
Don't most porshes, BMWs, Corvettes, etc etc come with conventional oil? Must be a reason for that.
For me it pays off. Right now it -10 F out side. Knowing that when I start my car in the morning my oil will be more like oil and less like syrup give me peace of mind. I drive 100 miles a day. Being able to extend my oil changes to 4500-5000 miles saves me money, and time.
The difference is cost isn't really that bad either. Its $33 every 10 weeks for me or $20 every 6 (not counting oil filter.. and the **** at the dealer). Kinda washes out in the end.
I always laugh when I read something like this because the recommended oil viscosity these days in this country has more to do with fuel economy and emissions standards than having your engine last long. Manufacturers are trying to squeeze more and more mpg out of their vehicles and one way to do this is to run thinner and thinner oils. They spend a lot of money alright. A lot of money trying to get cars more efficient and telling you to use a 5W-20 or 30 to be able to get good CAFE numbers is a lot cheaper than designing a more efficient motor.
The MPS manual in Europe and Australia specify that a 5W-40 can be used. So are the motors in the MPS's any less engineered than ours? Why do most turbocharged, high-performance cars in Europe go with a 5W-40?? Why are most of these 5W-40's labeled "Euro Blend"?
Changing oil weight isn't going save them the cost of redesigning a more efficient engine, its just gonna give slightly better results on whatever they come up with. While I agree with you car companies want to squeeze everything they can out of every car they sell to make higher proffit, i don't buy into the 'higher mpg' conspiracy. Is it a factor? Sure it is, but to argue that we know more about mazdas, then well... Mazda does, is a little silly. Keep in mind while they want to get the best specs out of a car they can, they also need to sell you a quality product. If they go around recommending the wrong oil, that wont serve them in the long run
Another thing to keep in mind, is as manufacturing techniques become better and tolerances on part dimentions become smaller, a thinner oil can be used. The better the part, or another way to look at it is the smoother the surface, the less it will wear.
As for the 5w-40, I would like to see if that is the suggested weight, or if it just another weight that is approved. And the weight used in other countries could be related to reasons other then just mpg. Remember one could argue on the other side of the fence you have the evil Exxon Mobils, Shells, Citgo, etc, with their lobbyists and shady deals, who want to make more money and get in bed with car companies to keep the cars guzzling gas. (im not saying i buy into that theory either... just an apposing argument )
All im saying is, mazda did their homework. If they recommend 5w-30, its probably fine... just remember to change your friggin oil!
