2007 Chevrolet Cobalt Owner's Manual - Page 313

Brakes Brake Fluid The brake master cylinder and, on manual transaxle vehicles, the clutch hydraulic system use the same reservoir. The reservoir is filled with DOT-3 brake fluid. If it is, you should have the brake and/or clutch system fixed, since a leak means that sooner or later the brakes and/or clutch will not work well, or will not work at all. So, it is not a good idea to top off the brake/clutch fluid. Adding fluid will not correct a leak. If you add fluid when the brake linings are worn, you will have too much fluid when you get new brake linings. You should add or remove fluid, as necessary, only when work is done on the brake/clutch hydraulic system. {CAUTION: See Engine Compartment Overview on page 284 for the location of the reservoir. 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 and/or clutch hydraulic system. If your vehicle has too much brake fluid, it can spill on 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 and/or clutch hydraulic system. When the brake fluid falls to a low level, the brake warning light will come on. See Brake System Warning Light on page 167. 313