2003 Honda S2000 Owner's Manual - Page 163

Cooling System Fill up to here RESERVE TANK RADIATOR CAP FILLER NECK 2. Turn the radiator cap counterclockwise, without pressing down on it, until it stops. This relieves any pressure remaining in the cooling system. 3. Remove the radiator cap by pushing down and turning counterclockwise. 4. The coolant level should be up to the base of the filler neck. Add coolant if it is low. Pour the coolant slowly and carefully so you do not spill. Clean up any spills immediately. Spilled coolant could damage components in the engine compartment. 5. Put the radiator cap back on. Tighten it fully. 6. Pour coolant into the reserve tank. Fill it to halfway between the MAX and MIN marks. Put the cap back on the reserve tank. Do not add any rust inhibitors or other additives to your car's cooling system. They may not be compatible with the coolant or engine components. 166 Maintenance