2004 Jeep Wrangler Owner's Manual - Page 241

MAINTAINING YOUR VEHICLE 241 Adding Coolant When adding coolant, a minimum solution of recommended 50% ethylene glycol antifreeze coolant in water should be used. Use higher concentrations (not to exceed 70%) if temperatures below -37°F (-38°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: Mixing coolant types will decrease the life of the engine coolant and will require more frequent engine coolant changes. Please note that 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. 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 cap should be inspected and cleaned if there is any accumulation of foreign material on the sealing surfaces. WARNING! The warning words DO NOT OPEN HOT on the cooling system pressure cap are a safety precaution. Never add coolant when the engine is overheated. Do not loosen or remove the cap to cool an overheated engine. Heat causes pressure to build up in the cooling system. To prevent scalding or injury, do not remove the pressure cap while the system is hot or under pressure. Coolant Level The coolant bottle provides a quick visual method for determining that the coolant level is adequate. The coolant level must be at the FULL mark or above the ADD mark on the bottle. The radiator normally remains completely full, so there is not need to remove the radiator cap unless checking for coolant freeze point or replacing coolant. Advise your 7