2008 Jeep Commander Owner Manual - Page 404

404 MAINTAINING YOUR VEHICLE • Use only high purity water such as distilled or deionized water when mixing the water/antifreeze (coolant) solution. The use of lower quality water will reduce the amount of corrosion protection in the engine cooling system. 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. NOTE: Mixing antifreeze/coolant types will decrease the life of the antifreeze/coolant and will require more frequent antifreeze/coolant changes. Cooling System Pressure Cap The cap must be fully tightened to prevent loss of antifreeze/coolant, and to insure that antifreeze/coolant will return to the radiator from the coolant recovery 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 antifreeze/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. • Do not use a pressure cap other than the one specified for your vehicle. Personal injury or engine damage may result.