Preliminary Checks
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 up to 2000 rpm with transmission in park or neutral for more airflow is recommended.
TRAILER TOWING:
Consult Trailer Towing owners manual. Do not exceed limits.
RECENT SERVICE OR ACCIDENT REPAIR:
Determine if any recent service has been performed on vehicle that may affect the 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).
- Service to electrically controlled viscous fan clutch
NOTE: If investigation reveals none of the previous items as a cause for an engine overheating complaint, refer to the COOLING SYSTEM DIAGNOSIS CHART.
These charts are to be used as a quick-reference only.
