2004 Chrysler PT Cruiser Owner's Manual - Page 267

MAINTAINING YOUR VEHICLE 267 Selection Of Coolant Use only the manufacturers recommended coolant, refer to Recommended Fluids, Lubricants and Genuine Parts for correct coolant type. 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. 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 coolant types will decrease the life of the engine coolant and will require more frequent coolant changes. 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 recovery bottle. CAUTION! Failure to use the proper antifreeze could cause radiator plugging and engine overheating. Do not mix antifreeze brands or use plain water alone or alcohol based antifreeze products. Do not use additional rust inhibitors or antirust products, as they may not be compatible with the radiator coolant and may plug the radiator. Adding Coolant When adding coolant, a minimum solution of 50% ethylene glycol antifreeze coolant in water should be used. 7