Picture of Time to change oil? How do you know when it is time
to change your engine oil? Maybe there is a sticker on your door
that is visible when you open the door and crane your neck down
to waist level. But, you still need to subtract the mileage
figure on the sticker from the reading on your odometer. It can
work, but it is not a great system.  Step 1: Use the Change Oil
light?  Picture of Use the Change Oil light? Modern automobiles
have a Change Oil light on the instrument display. See the green
box. It lights when it is allegedly time to change your oil.
But, it is only a computer's guess that it is time to change
your oil. Your engine's computer notices the amount of city
driving you do in comparison to highway driving and guesses that
your oil has reached a certain level of contamination from
engine wear, water vapor in the crankcase, acids, and engine
blow-by gasses. A truly accurate assessment of your oil's
condition would require testing in a laboratory.  The Low Tire
Pressure light next to the