2005 Dodge Viper Owner's Manual - Page 185

MAINTAINING YOUR VEHICLE 185 Adding Coolant When adding coolant, or refilling the system, a minimum solution of 50% recommended HOAT ethylene glycol engine coolant (antifreeze) and distilled water should be used. Use higher concentrations (not to exceed 70%) if temperatures below 34°F ( 37°C) are anticipated. Use only high purity water such as distilled or deionized water when mixing the water / antifreeze solution. The use of lower quality water will reduce the amount of corrosion protection in the engine cooling system. NOTE: It is the owner's responsibility to maintain the proper level of protection against freezing according to the temperatures occurring in the area where the vehicle is operated. WARNING! Never add coolant to the radiator when the engine is overheated. Do not loosen or remove pressure cap to cool overheated engine. The coolant is under pressure and severe scalding could result. Cooling System Pressure Cap The cap must be fully tightened to prevent loss of coolant, and to insure that coolant will return to the radiator from the coolant reserve tank. The pressure cap should be inspected and cleaned if there is any accumulation of foreign material on the sealing surfaces. 7