Engine Cooling System
7 LessonsMaster cooling system diagnosis — from thermostats to head gaskets.
Overview
The cooling system maintains engine temperature within a narrow operating range. Too cold and efficiency drops. Too hot and you destroy the engine. This module covers water pumps, thermostats, radiators, cooling fans, heater cores, and the diagnostic techniques that find problems before they become catastrophic.
Key Components
- Water pump
- Thermostat
- Radiator and cooling fans
- Heater core
- Coolant reservoir and pressure cap
How It Works
Coolant circulates from the engine through the radiator, where heat is transferred to the air. The thermostat regulates flow to maintain optimal operating temperature. The water pump drives circulation, and the pressure cap raises the boiling point of the coolant.
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Join the Nation — FreeCommon Problems
- Thermostat stuck open causing overcooling
- Water pump bearing failure or impeller erosion
- Radiator blockage from stop-leak products
- Heater core leaks or blockage
- Head gasket breach contaminating coolant
Diagnostic Tips
- Pressure test the system to find external leaks
- Chemical block test (combustion gas test) for head gasket
- Infrared temp gun to check thermostat opening
- Never open a hot radiator cap
Related Systems
Engine Mechanical
12 LessonsUnderstand how internal combustion engines work — from the block to the valvetrain.
Engine Lubrication
4 LessonsLearn oil systems, viscosity, and why proper lubrication is the difference between 100K and 300K miles.
Fuel System
6 LessonsUnderstand fuel delivery from tank to injector — GDI, port injection, and everything in between.
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