Diagnostic Strategies

PRELIMINARY CHECKS

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.
^ Increasing engine speed for more air flow is recommended.

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.

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).