Cooling System Repair

Coolant from the engine is circulated from the left hose, through the radiator, cooled by the fan (center), and returns to the engine via the right hose.

Coolant from the engine is circulated from the left hose, through the radiator, cooled by the fan (center), and returns to the engine via the right hose.

Repairs to the engine’s cooling system typically mean replacing the coolant pump, the thermostat, and/or the radiator. The Fix-It Club offers basic instructions on how to perform these three important jobs.

Replace a Coolant Pump

The coolant pump, also know as a water pump, circulates coolant (a mixture of coolant and water) through the engine, into the radiator, and return to the engine. The coolant pump typically is installed on the front of the engine and has a round pulley and belt. The engine’s rotation is transferred to the pump.

To replace a coolant pump, drain coolant from the engine, remove the pump belt, and disconnecting the pump from the engine. Take the pump to an auto parts store for an exact match and install it in reverse order.

Replace a Thermostat

The simplest and most common repair to cooling systems is replacing the thermostat.

Car Words

thermostat is a valve that opens and closes based on temperature, regulating the flow of coolant in an engine. Thermostats have a specific temperature range, called a set point at which they open or close to keep the coolant’s temperature within the designated range.

Replacing the thermostat on your car’s cooling system may be easy or difficult, depending on how the engine was designed. On most cars, the thermostat is located inside a metal housing between the engine and the radiator’s top hose. So replacement requires that you drain coolant from the cooling system, remove the hose, remove the housing, and finally remove the thermostat. Install a new one in reverse order. Make sure that you install an exact replacement thermostat because they have different temperature set points.

Replace a Radiator

Modern radiators are much smaller than their grand-daddies. So removal should be easier. However, because of tight clearances in modern engine compartments, radiator removal and replacement may require moving everything else. The usual steps are:

1. Drain the cooling system.

2. If your car is equipped with an automatic transmission, disconnect its coolant lines from the radiator.

3. Loosen the radiator hose clamps and detach the hoses.

4. If the cooling fan (pictured) is attached to the radiator, remove it.

5. Loosen and remove bolts holding the radiator to its frame.

6. Remove any other components that are attached to or in the way of removing the radiator.

7. Carefully lift the radiator from the frame.

8. Reinstall the radiator and coolant in reverse order.

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