An engine’s cooling system is vital to its function and safety. Cooling system dysfunction is a factor in almost 50% of all engine failures.
Moreover, accidents involving an engine overheating pose a high risk of injury. The majority of injuries caused by auto hazards—including 96.5% of burns requiring hospitalization—stem from overheated vehicle radiators.
Keeping your car or truck’s cooling system functioning well can save your engine—and, potentially, your life. Learn how to maintain your truck's cooling system and prevent overheat in Point Spring’s expert guide.
Automotive Cooling Systems Explained: FAQ’s & Key Terms
An auto cooling system is crucial to an engine’s function and safety. To maintain yours effectively, it's important to understand the system’s parts, and how they function together.
What Is A Vehicle’s Cooling System?
The engine cooling system draws excess heat generated by the engine during combustion away from volatile components, to prevent damage from overheating.
The system is a circuit that transfers heat: first to flowing coolant, then to flowing air, until it ultimately disperses excess heat safely outside. The system heats and cools the coolant in each cooling cycle. It uses the following parts:
Coolant
Coolant is a chemical mixture of distilled water and antifreeze. Antifreeze is a glycol-, organic acid-, or inorganic acid-based compound.
Water Pump
A coolant system’s water pump forces coolant through the system, controlling its flow. Most water pumps use a rotating impeller to transform the force of the engine’s belt into centrifugal force. But, some pumps are electric.
Radiator
The radiator is a heat exchanger. It transfers heat from the heated coolant to cool air, and it expels both fluids post-exchange.
Radiator Cap
The radiator cap is a pressure relief valve. It controls the pressure within the system, which alters the coolant's boiling point. This lets the engine run at a higher temperature, temporarily. It also prevents leaks.
Fan
The radiator fan pushes air through the system. Its function is similar to that of the water pump, but for air.
Thermostat & Temperature Gauge
The thermostat is a valve that restricts or increases the flow of coolant, to maintain an optimal engine temperature. It uses a thermo-expansive wax cylinder, which triggers valve opening and closure in response to heat.
The temperature gauge reads the current engine temperature from the wax cylinder. Then, it displays that temperature on the dashboard.
Hoses
Cooling system hoses are flexible, silicone tubes that carry coolant between the engine, radiator, reservoir, and overflow tank.
How Does An Engine Cooling System Work?
The cooling system moves the engine’s heat to a safer location by circulating coolant, a chemical mixture of water and antifreeze. As the water pump pushes the coolant through the system, the coolant passes through the engine block and cylinder, where it absorbs excess heat.
Then, the heated coolant flows to the radiator (heat exchanger), where it meets an inflow of relatively cooler, ambient air. The air absorbs and dissipates much of the coolant's heat.
The now-hot air is then discharged through external vents. Meanwhile, the re-cooled coolant flows out to the water pump, starting another cooling cycle.
Cooling Systems In Heavy-Duty Vehicles: Unique Properties
HDVs have powerful engines, and they run at a higher intensity than other vehicles. As a result, they typically have more robust cooling system components, larger radiators, and specialized coolant mixtures.
Car Cooling Systems Vs. HDV Systems
There are four key differences between car Cooling systems and truck systems.
Different Coolant Types
Cars and trucks use different types of coolant. They are not interchangeable.
Cooling Fan Clutch Function
Many cars and trucks use a fan clutch to regulate the cooling system fan. But, cars are more likely to forgo the fan clutch in favor of an electric fan.
Moreover, truck fan clutches have higher duty ratings. A truck’s fan clutch typically uses higher-pitched fan blades than the blades of a car, as they need to deal with greater resistance.
As a result, fan clutch cleaning and maintenance is a crucial task when maintaining a truck’s cooling system. Yet, it may not be necessary when caring for a car’s system.
Continual / Secondary Cooling System
Cars only have one cooling system.
Certain heavy-duty vehicles and trucks incorporate a secondary cooling system. It uses a separate coolant to transfer heat away from high-intensity components. This is typically done via continuous cool sprays, and it prevents scaling on heat exchangers.
Aluminum Components
Both lightweight trucks and heavy-duty commercial vehicles use more aluminum components than cars. In fact, the typical pickup truck uses 30% more aluminum than the average passenger car.
As a result, it's crucial to use aluminum-compatible coolants. Abide by a maintenance schedule designed to prevent aluminum oxidation or degradation.
Maintenance Differences: Car Cooling System Vs. Heavy-Duty Vehicle Cooling System
If you're used to maintaining a car’s cooling system, keep in mind these differences during truck cooling system maintenance. Remember:
HDV radiators require more frequent cleaning and de-scaling.
Typically, truck coolant needs more frequent replacement than car coolant.
Trucks with extended-life coolants (ELCs) require specific maintenance tests.
With these comparisons in mind, effective maintenance of your truck's cooling system is doable.
Truck Cooling System Maintenance: Overview & Principles
There are four keys to solid truck cooling system maintenance.
First, make sure you're using the right coolant. Second, monitor your system with effective tools. Regular monitoring and inspections are indispensable.
Then, learn to clean your system, and do so regularly. Finally, stick to a regular maintenance and repair schedule.
Abide by these principles, and you’ll be on the right road.
How To Maintain Your Commercial Vehicle Cooling System
To maintain your heavy-duty vehicle’s cooling system, you'll want to use a thorough maintenance checklist. It's also wise to stick to a regular maintenance schedule.
Before diving into those resources, consider some of these useful strategies, tips, and tricks.
Top 5 Engine Cooling System Strategies, Tips & Tricks
These tips make cooling system maintenance easier and safer.
1. Only Mix Coolant With Distilled Or Deionized Water, Never Tap
Tap water includes minerals that can damage your system. Deionized water is the pure chemical form of water, and doesn't carry risks to your engine.
2. Keep Your Radiator Cap Tight
A loose radiator cap is a common cause of coolant leaks. Keep it tight, and you cut your risk of leaks down.
3. Use The Right Coolant & Additives
Most trucks use ethylene glycol (EG), propylene glycol (PG), or inorganic acid technology (IAT). Research your truck's specifications to choose the right coolant for its system.
Consider supplemental additives if using IAT.
4. Handle & Store Coolant Safely
Store coolant in a tightly sealed container. Keep it in a cool, dry place. Use a funnel and PPE to prevent spills when pouring.
5. Clean Debris From Radiator Cooling Fins With Soft Brush
Coolant fins need to be cleaned more frequently than a full flush is necessary. Between flushes, gently clean away accumulated carbon and debris with a soft, nylon brush.