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 section of 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.

Cooling System Diagnosis Chart (Part 1):

Cooling System Diagnosis Chart (Part 2):

Cooling System Diagnosis Chart (Part 3):

Cooling System Diagnosis Chart (Part 4):

Cooling System Diagnosis Chart (Part 5):

Cooling System Diagnosis Chart (Part 6):