See also:

Underbody
Flush the complete underside of your vehicle frequently. Keep body and door drain holes free from packed dirt. ...

Brake fluid
The fluid level will drop slowly as the brakes wear, and will rise when the brake components are replaced. Fluid levels between the MIN and MAX lines are within the normal operating range; ...

Measuring techniques
Your best source of information about actual fuel economy is you, the driver. You must gather information as accurately and consistently as possible. Fuel expense, frequency of fill-ups or fuel ga ...