Checking Brake Fluid
You can check the brake fluid without taking off the cap.

Look at the brake fluid reservoir. The fluid level should be above MIN. If it is not, have your brake system checked to see if there is a leak.
After work is done on the brake hydraulic system, make sure the level is above the MIN, but not over the MAX mark.
See also:
Driving in Rain and on Wet Roads
Rain and wet roads can reduce vehicle traction
and affect your ability to stop and accelerate. Always
drive slower in these types of driving conditions
and avoid driving through large puddles an ...
Engine Oil Additives / Engine Oil
Flushes
Do not add anything to the oil. The recommended oils
with the starburst symbol that meet GM Standard
GM6094M are all that is needed for good performance
and engine protection.
Engine oil system ...
Certification/Tire Label
A vehicle specific Certification/Tire label is found
on the rear edge of the driver’s door. The label
shows the size of your vehicle’s original tires and
the inflation pressures needed to obt ...
