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DIAGNOSIS AND TESTING PRELIMINARY CHECKS ENGINE COOLING SYSTEM OVERHEATING Establish what driving conditions caused the com- plaint. Abnormal loads on the cooling system such as (1) PROLONGED IDLE, VERY HIGH AMBIENT TEMPERATURE, SLIGHT TAIL WIND AT IDLE, Driving techniques that avoid overheating are: end of normal range. • Increasing engine speed for more air flow is rec- ommended. (2) TRAILER TOWING: Do not exceed limits. (3) RECENT SERVICE OR ACCIDENT REPAIR: formed on vehicle that may effect cooling system. • Engine adjustments (incorrect timing) • Slipping engine accessory drive belt • Brakes (possibly dragging) • Changed parts (incorrect water pump) • Reconditioned radiator or cooling system refill- ing (possibly under filled or air trapped in system). NOTE: If investigation reveals none of the previous These charts are to be used as a quick-reference only. Refer to the group text for information. COOLING SYSTEM DIAGNOSIS–DIESEL ENGINE CONDITION POSSIBLE CAUSES CORRECTION TEMPERATURE GAUGE 1. Diesel engines, due to their inherent 1. The low gauge reading may be 2. Is the temperature gauge connected to 2. Check, the engine temperature 3. Is the temperature gauge operating 3. Check gauge operation. Refer to 4. Coolant level low in cold ambient 4. Check coolant level in the 5. Improper operation of internal heater 5. Inspect heater and repair as 7 - 8 COOLING SYSTEM XJ 2000 JEEP CHEROKEE |