Originally Posted by Robin330i
17000 miles is ok with modern good quality oils.
The reason why I know is because I deal with oil samples for our durability cars at work (I'm an engine development engineer at a luxury car brand in Crewe.......) - the oil sample results I get back for similar mileages show that oil viscosity is still acceptable and lubrication properties are still high enough for component protection.
That's not going to be a popular opinion. Not least because it's more than just an opinion
My "research" so far does seem to suggest that expensive synthetic oils are superior not in the amount of protection they offer but in how long they can do it for. So if you are running frequent changes you may as well save the money and use cheaper oil (warranty issues aside). Basically, if you are going to drink 4 cans of beer and throw away the rest, the 6-pack is a better buy than the 12-pack.