Diagnostic Strategies

ENGINE COOLING SYSTEM OVERHEATING
Establish what driving conditions caused the complaint. Abnormal loads on the cooling system such as the following may be the cause:
PROLONGED IDLE, VERY HIGH AMBIENT TEMPERATURE, SLIGHT TAIL WIND AT IDLE, SLOW TRAFFIC, TRAFFIC JAMS, HIGH SPEED, OR STEEP GRADES.
Driving techniques that avoid overheating are:
^ Idle with A/C off when temperature gauge is at end of normal range.
^ Increase engine speed for more air flow is recommended.
1. TRAILER TOWING:
Consult Trailer Towing section of owners manual. Do not exceed limits.
2. AIR CONDITIONING; ADD-ON OR AFTER MARKET:
A maximum cooling package should have been ordered with vehicle if add-on or after market A/C is installed. If not, maximum cooling system components should be installed for model involved per manufacturer's specifications.
3. RECENT SERVICE OR ACCIDENT REPAIR:
Determine if any recent service has been performed on vehicle that may effect cooling system. This may be:
^ Engine adjustments (incorrect timing)
^ Slipping engine accessory drive belt(s)
^ Brakes (possibly dragging)
^ Changed parts. Incorrect water pump, or pump rotating in wrong direction due to belt not correctly routed
^ Reconditioned radiator or cooling system refilling (possibly under filled or air trapped in system).