Oldsmobile 2003 Silhouette Owner's Manual page 347

There are only two reasons why the brake fluid level
in the reservoir might go down. The first is that the brake
fluid goes down to an acceptable level during normal
brake lining wear. When new linings are put in, the fluid
level goes back up. The other reason is that fluid is
leaking out of the brake system. If it is, you should have
your brake system fixed, since a leak means that
sooner or later your brakes won't work well, or won't
work at all.
So,
it
isn't a good idea to "top off your brake fluid.
Adding brake fluid won't correct a leak. If you add fluid
when your linings are worn, then you'll have too much
fluid when you get new brake linings. You should add
(or remove) brake fluid, as necessary, only when work
is done on the brake hydraulic system.
1.
, ' -
have too much brake f L J , it can spi.. an
the engine. The fluid will burn if the engine is
hot enough. You or others could be burned,
and your vehicle could be damaged. Add brake
fluid only when work is done on the brake
hydraulic system. See "Checking Brake Fluid"
in this section.
BRAKE
When your brake fluid falls to a low level, your brake
warning light will come on. See Brake System Warning
Light on page 3-44.
What to Add
When you do need brake fluid, use only DOT-3 brake
fluid. Use new brake fluid from a sealed container
only. See Part D: Recommended Fluids and Lubricants
on page 6- 16.
Always clean the brake fluid reservoir cap and the
area around the cap before removing it. This will help
keep dirt from entering the reservoir.
5-40