2004 Jeep Wrangler Owner's Manual - Page 242

242 MAINTAINING YOUR VEHICLE service attendant of this. As long as the engine operating temperature is satisfactory, the coolant bottle need only be checked once a month. When additional coolant is needed to maintain the proper level, it should be added to the coolant bottle. Do not overfill. Points To Remember NOTE: When the vehicle is stopped after a few miles of operation, you may observe vapor coming from the front of the engine compartment. This is normally a result of moisture from rain, snow, or high humidity accumulating on the radiator and being vaporized when the thermostat opens, allowing hot coolant to enter the radiator. If an examination of your engine compartment shows no evidence of radiator or hose leaks, the vehicle may be safely driven. The vapor will soon dissipate. • Do not overfill the coolant bottle. • Check coolant freeze point in the system. • If frequent coolant additions are required, or if the level in the recovery bottle does not drop when the engine cools, the cooling system should be pressure tested for leaks. • Maintain coolant concentration at 50% ethylene glycol antifreeze (minimum) in water for proper corrosion protection of your engine that contains aluminum components. • Make sure that the radiator and coolant bottle hoses are not kinked or obstructed. • Do not change the thermostat for summer or winter operation. If replacement is ever necessary, install ONLY the correct type thermostat. Other designs may result in unsatisfactory cooling performance, poor gas mileage, and increased emissions. Hoses and Vacuum/Vapor Harnesses Inspect surfaces of hoses and nylon tubing for evidence of heat and mechanical damage. Hard or soft spots, brittle rubber, cracking, tears, cuts, abrasions, and excessive swelling indicate deterioration of the rubber.