How Does the Cooling System Work?

Cooling systems work by sending coolant through passages in the engine block and heads. As the coolant flows through these passages, it picks up, or absorbs, heat from the engine. The heated fluid then makes its way through rubber hoses to the radiator. As it flows through the radiator, the hot liquid is cooled by the air stream entering the engine compartment from the grill in front of the car. Once cooled, it returns to the engine to absorb more heat. The water pump has the job of keeping the fluid moving through this system of plumbing and hidden passages.

Getting Your System in Shape:

Start with a seven-point preventative cooling system maintenance check (as recommended by the NARSA). The seven-point check is designed to identify any areas that need attention and consists of:

• Visual inspection of all cooling system components, including belts and hoses
• Radiator pressure cap test to check for the recommended system pressure level
• Thermostat check for proper opening and closing
• Pressure test to identify any external leaks to the cooling system parts; including the radiator, water pump, engine coolant passages, radiator, and heater hoses, and heater core
• Internal leak test to check for combustion gas leakage into the cooling system
• Engine fan test for proper operation
• System power flush and refill with a 50/50 concentration of coolant and water

Common Causes of a Weak System:

Poor Circulation

The coolant follows a path that takes it from the water pump, through passages inside the engine block where it collects the heat produced by the cylinders. It then flows up to the cylinder head(s) and then flows out past the thermostat into the radiator and starts the process all over again. If the water pump is bad, or the radiator and passages are blocked or restricted it will cause poor coolant flow and can lead to overheating.

No Thermostat/Removed Thermostat

There is a mistaken belief that if you remove the thermostat, your truck will run cooler. This couldn’t be further from the truth. Removing the thermostat allows uncontrolled circulation of coolant through the system. The coolant moves so fast, that it cannot absorb the heat from the engine as it passes through AND will not be properly cooled as it races through the radiator. Most times, the engine will run even hotter than before even if your temp gauge says otherwise.

Missing or Inefficient Radiator Fan or Shroud

Fans are there to keep the airflow going through the radiator while the vehicle is going slow or is stopped with the engine running. If these fans are not designed for the job, they may not be pulling enough air through the radiator to effectively cool your engine. Additionally, if you do not have a fan shroud to direct the vacuum created by the fan onto your radiator, you are simply stirring up hot air from the engine compartment. Don’t underestimate the importance of a good working fan and shroud combination.

Non-Functioning Pressure Cap

As coolant gets hot, it expands. Since the cooling system is sealed, this expansion causes an increase in pressure in the cooling system. This is a normal part of the design of the system and raises the boiling point of your coolant. If the cap cannot hold pressure, your system will boil sooner and coolant will be allowed to escape from the radiator through the overflow.

Did You Know…?

Antifreeze/Coolant should be replaced every 2 years

Running your truck's heater if your engine is overheating can help cool the coolant and potentially reverse the overheating condition.