In Europe, Ford say, that man should use semi-synthetic oil 5W-30 and change every 15 000 km ( ca. 9000 miles) or every year.
Other brands (Nissan or Citroen, for example) need full synthetic oil, and change every 20 000 or even 30 000 km... or every 2 years.
The oil grade is 5W-40 or 0W-40 usually there.
And I've heard, that it could be longer, but nowadays there's a problem with oil filters.
Because filters are the weakest point... It can filter properly not so long...
But the oil can do its job without problem...
Conventional oil is available only in 15W-40 and up grade, so people use it in old cars only (pre '90), so I can't tell how often they change.
I personally use semi synthetic, and change it every 10 000 km (ca. 6250 miles) or full synthetic and change every 15-20 000 km (10-12 000 miles)
I have no problem with oil consumption, or ride herself
I know that american engines are little bit different than european, but in my Mondeo, there's the same Duratec25 like in CSVT... and in manual, Ford ask to change oil every 10 000 miles...and this is american engine... even Motorcraft spark plugs and belts are "made in the U.S.A."
Maybe larger engines (which we don't have here, so we don't have manuals for Europe) need often oil changes, but Duratec25 and Duratec30 (please check Ford Mondeo ST220) do not need.
And we are talking about synthetic oli change in 2.5 Duratec engine.
So... if we can do it not so often, why you should?
Maybe if someone leaves in extreme dusty condition... but in "normal" climate?
Riding style and roads?
I usually drive 10 miles to work and 10 miles back, 100 mph higway, then 3 miles in the city, most the time idling (high traffic)...
Outside the city (going for skiing, or river, or just to spend my time) usually 60 mph...
I drive ca. 16 000 miles per year.
Weather?
Temperature in the year is from -18 or -4 F in the cold winter, usually 23-32 F in the winter, up to 22-86 F in the summer...
I don't know the real reason, that you should change your synthetic oil every 3000 miles...
Conventional - that's clear - it's worn earlier, because it's not ideal.
But synthetic? It is. Every molecule has it's own place, it's clean... it's synthetic... Every detail is made by engineers...
Maybe, the reason is, that it was necessary in old days, and now it'a a tradition (my grandpa did, my father also, so do I), and it's perfect for oil companies, that every American buys 6 or 10 qrts of oil 4 or 5 times a year...
I buy 6 qrts twice a year for my car, and once a year for my wife's one (she drives to work only).
