Troubleshooting - Toyota 4A-FE Repair Manual

C0-4 COOLING SYSTEM - Troubleshooting
TROUBLESHOOTING
Problem Possible cause Remedy Page
Engine overheats Check coolant Replenish coolant
Water pump drive belt loose or missing Adjust or replace belt
Dirt, leaves or insects on radiator Clean radiator
Hoses, water pump, thermostat housing, Repair as necessary
radiator, heater, core plugs or head gasket
leakage
Thermostat faulty Check thermostat C0-13
Ignition timing retarded Set timing
Electric cooling system faulty Inspect electric cooling system C0-21
Radiator hose plugged or rotted Replace hose
Water pump faulty Replace water pump
C0-6
Radiator plugged or cap faulty Check radiator
C0-15
Cylinder head or block cracked or plugged
Repair as necessary
HINT: The thermostat is equipped with a by-pass valve, if the engine tends to overheat, removal of the ther-
mostat would have an adverse effect, causing a loss of cooling efficiency.