hello, i also plan on changing my oil at 1000 miles. i have done so on all of my new cars, but im pretty sure our mirages take 0w20 synthetic oil. i also plan on changing the oil at the next 3750 miles just to see how bad it realy is, usualy its still good for a bit so i would say with a good quality oil filter you should be able to go to 7500k no problem. im very picky on this subject so i will probably be changing mine every 5k or so. hope this helps.
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View my fuel log 2014 Mirage es 1.2 manual: 43.7 mpg (US) ... 18.6 km/L ... 5.4 L/100 km ... 52.5 mpg (Imp)