Heavy-duty diesel engines create a lot of heat and, as such, need strong coolant systems to keep them operating at an adequate temperature. Although these systems are generally self-contained and don’t need a lot of maintenance, problems do arise every now and then. Sometimes road debris can come in contact with one of your components, or something may break simply due to old age. Regardless, by taking a proactive stance toward your coolant system’s maintenance, you can reduce the risk of an unexpected breakdown and save yourself a lot of money in the long run. Today we’ll be discussing everything you need to know about your truck’s coolant system, including its anatomy, how it all works, and what symptoms to look out for should it start to malfunction.
Truck engine cooling system anatomy
A properly functioning cooling system is made up of six key components: a cooling fan, radiator, water pump, thermostat, rubber hoses, and antifreeze/coolant. If one component fails, it can set off a chain reaction that sends your heavy-duty truck to a neighboring shop for repairs.
- Water pump: The water pump is responsible for continually circulating coolant from the radiator throughout the whole cooling system of a heavy-duty truck. It is referred to as the "heartbeat" of the system. If your heavy-duty truck starts to overheat, there may be a problem with the water pump.
- Antifreeze/coolant: Coolant comes in various colors, and the kind you use depends on your heavy-duty truck. The coolant's duty, regardless of hue, is to go through the engine and absorb radiant heat.
- Cooling fan: This device is intended to kick on when the coolant temperature rises too high and run until the liquid cools down.
- Radiator: The radiator's function is to disperse the radiant heat that the coolant absorbs, therefore cooling the engine.
- Thermostat: Your heavy-duty truck’s thermostat dictates when your various cooling components engage.
- Rubber hoses: Your hoses and reservoirs are used to funnel coolant to and from your engine and radiator.
Engine cooling system failure warning indications
An overheating heavy-duty truck is the most typical indicator of a failing or malfunctioning engine cooling system. However, other warning indicators can appear before the engine overheats, which may allow you to spot the issue long before it happens.
A rising thermometer might be your first indication of problems. Pull over immediately if the needle drops into the red "danger" zone.
- Low coolant levels: Before long-distance excursions, always check your coolant level. If it’s lower than usual, you may have a leak or old coolant.
- Fluctuating Temperature: If your engine temperature is fluctuating erratically, you may have a problem with your thermostat.
How to prevent issues with the engine cooling system
Of course, regular maintenance is the best course of action but do your homework beforehand before blowing your budget. Additionally, the recommendations listed below are just that—recommendations. For additional information on your heavy-duty truck's cooling system, please see the operator's handbook and service documents for your particular truck. Let's revisit the six elements of the engine cooling system.
The level of your coolant reservoir tank's antifreeze/coolant should be above the "cold minimum line." The majority of semi-trucks need 12–14 total gallons. Regularly check and replenish as required.
- Cooling fan: Cooling fans do not need routine maintenance, but rather, routine inspection. Look for worn fan bearings and listen for air leaks to ensure the system is fully functional. To be cautious, you should replace the fan if the engine makes strange sounds, the coolant level drops, or the temperature rises.
- Radiator: Check for corrosion and look for cracks and bulging in the radiator cap. Additionally, ensure sure the coolant is pure—contaminant-free. Replace the radiator if it has sludge accumulation or coolant leaks.
- Rubber hoses: Check the hoses for leaks and breaks while checking the radiator. Replace belts and tensioner arms every two years.
Be sure to proactively maintain and inspect your coolant system on a regular basis to reduce the risk of unexpected breakdowns. By replacing parts and flushing out old coolant when necessary, your truck will run better and last longer.