Chevrolet 2003 Blazer Owner's Manual page 335

I
4. Raise the vehicle by turning the jack handle
clockwise. Raise the vehicle far enough off the
ground so there is enough room for the spare tire to
fit underneath the wheel well.
5. Remove all the wheel nuts and take off the fiat tire.
6. Remove any rust or dirt
from the wheel bolts,
mounting surfaces
and spare wheel.
Rust or dirt on the wheel, or on the parts to
which it is fastened, can make the wheel nuts
become loose after a time. The wheel could
come off and cause an accident. When you
change a wheel, remove any rust or dirt from
the places where the wheel attaches to the
vehicle. In an emergency, you can use a cloth
or a paper towel to do this; but be sure to use
a scraper or wire brush later, if you need to, to
get all the rust o r dirt off.
5-72