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Cooling System Repair

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By Aaron Turpen

What Can Go Wrong

Your automobile's cooling system is what keeps the engine core running at the optimum temperature for efficiency. Peripherally, it also provides heat for the passenger cabin and window defrost functions.

For detailed information on your automotive air conditioning system and repair, follow this link)

Common problems with a cooling system include:

  • Coolant (anti-freeze) leaks
  • Improper circulation of coolant
  • No in-cab heat or defrost
  • Engine overheating or staying too cold

Each of these problems is likely due to a different issue in each of the cooling system's components. So understanding how it works will go a long way towards diagnosis and cooling system repair.

How Your Vehicle's Cooling System Works

The cooling system has several basic components, all of which act in concert for a circular flow of coolant that does each of the jobs assigned to the system.

The radiator at the front of the vehicle holds the anti-freeze (coolant) and gives access to the maintenance person for adding, draining, and replacing fluid. In most vehicles, roughly 2/3 of the coolant being used will be located in the radiator when the engine is not running. The rest will be in the bottom of the engine block.

From the radiator, hoses carry the fluid to the engine block, with flow controlled by a thermostat and entering at the water pump which pushes the fluid through from the bottom of the radiator to the top of the engine's core.

The engine core itself has channels forged into it through which the coolant flows, cooling the bottom of the engine heads, the engine block itself, and sometimes sending heated coolant to the fuel injection and air intake heads to preheat them via convection.

Shunts from the back of the engine block will also allow hot fluid to be sent into the cabin through the heater core, which provides hot air for the passengers and defrost systems.

Where Common Problems Occur and Cooling System Repair

Knowing how the system circulates, common problems can be easily diagnosed. Leaks are most often at the hose connection points at the top or bottom of the radiator and to and from the heater core. Some leaks may be when the seal fails on the water pump or in the engine block itself (the latter most often seen as ìwhite smokeî as the coolant is burned in the combustion process and sent out the tailpipe).

When the engine overheats or stays too cold, it's due to improper circulation of the coolant. Either there is not enough anti-freeze for the pump to circulate it at volume or the thermostat or water pump have ceased working. If the problem is an engine that's too cool, it's likely the thermostat, but if it's overheating, it's likely the pump.

If there is no heat inside the passenger compartment and heat fails to come out of the vents for defrost, then a problem exists at the heater core and cooling system repair is needed. Usually this is due to the valve that is opened when the heat is selected on the air conditioning control panel, but it can also be due to a plugged or broken heater core that is not circulating fluid.

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