Quote:
ORIGINAL: urielaudi
well the point was if your oil looks dark it means you drove that oil for a while, and its burnt
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Nope, nothing "burnt" about it. The reason your oil starts looking dark is that it is carrying various combustion byproducts in suspension. That said, there is absolutely zero science that shows that black oil (that still has a useful additive pack) will protect an engine one iota worse that brand new oil. The flip side is that there are a number of scientific studies that show that new oil actually
increases engine wear for the first thousand miles or two. While I think this has yet to be definitively proven, it is an interesting datapoint none-the-less.
For my part, I submit that the best thing you can do for your engine regarding lubrication is to buy the best oil you can and leave it in there for as long as it is good. The trick here is figuring out how long the oil can last, and to that end, many manufacturers, GM, Honda, and BMW among others, are equipping their cars with Oil Life Monitors (OLMs) to aid in answering that very tricky question. For cars not so equipped, having a few UOAs performed can help you nail down a good OCI
for your car and only you car.
FWIW, I've had UOAs run on both of our current (non-OLM equipped) cars, and said UOAs indicate that Mobil 1 0W-40 is good for ~12,500 miles. Given that I want to err a tad on the conservative side, I usually target the oil changes at about 10,000 miles (which usually means I get to the oil change by 11,000). Even with OCIs that are more than 50% beyond the factory recommendation I was delighted to see that all of the honing marks were still on the cylinder walls of our oldest vehicle (which had 143,625 miles on it at the time) last summer after I yanked the heads off to replace the head gaskets (a shop diagnoseda blown head gasket due to a coolant leak into the oil, a leak that turned out to have been from a ten cent "O" ring in the timing cover, but that's another story).
RE: Quick quesiton
