DIY Cost: $ 10 - 15 Est. Time: 2 - 3 mins Difficulty: Very Easy Summary Step-by-step instructions on how to add and check brake fluid any 2016-2020 Kia Optima. What you will need DOT 3 or DOT 4 (Brake Fluid) Only use what is noted on the top of the brake fluid cap. Procedure Open the hood, pull the hood release under the dashboard and go in front of the vehicle. Then unlock the hood latch and pull the hood up until the hydraulic hood strut locks. Locate the brake fluid reservoir next to the firewall on the driver's side of the engine compartment. Check on the fluid level, shake the reservoir and look at the reservoir's indicator where the fluid lies. If the fluid level is on the maximum level, no need to add brake fluid. I If the fluid level is below or on the minimum level add brake fluid. To add brake fluid, open the cap by turning it counterclockwise. Use the brake fluid recommended by the vehicle's manufacturer or look at the cap to know what brake fluid to use. Make sure that the brake fluid you use is freshly sealed and not opened to prevent moisture from the fluid. Close the cap by turning it clockwise and check the fluid level again. Notes The recommended brake fluid type is also listed in your owner's manual. The recommended brake fluid type is also noted on the top of the cap for the brake fluid reservoir. Do not allow the brake fluid to spill on the paint of the vehicle. If brake fluid gets on the paint, wash it off with water. Brake fluid can damage the paint. Note that a brake light staying on at startup can indicate a problem with the brake system, but it can be an issue with the charging system or battery in some cases. You should not lose brake fluid regularly. If you are losing brake fluid, have the brake system checked by a mechanic immediately. If your brake warning light (or ABS light) comes on or is flashing while driving or at startup, stop and check the brake fluid level. Driving with the brake light on can put you, your passenger, and others at risk.