5 Things You Need to Know About Your Engine’s Cooling System

Heavy duty engines have evolved. They demand more from your cooling system. Know how to maintain your radiators, charge air coolers and more!
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Maintaining Your Heavy-Duty Truck’s Cooling Systems for Optimal Performance

You expect a lot from your truck’s engine. Your vehicle’s performance is paramount and downtime can cost you big time. Your business’ success is why it’s important to perform proper inspection and maintenance of all your heavy-duty truck systems/components, especially when it comes to your heavy duty cooling systems.

If you are a fleet owner, oversee an agriculture company or an independent operator, you know that if your vehicle is in the shop or service center, you are losing money due to downtime. Knowing how to properly maintain your cooling system to ensure continual efficient performance and dependability, can help prevent this.

Avoid unnecessary repairs and downtime by maintaining your cooling system. In this article, we’ll explain the importance of your engine’s cooling system, break down the main components of your engine’s cooling system, and explain how to prevent costly repairs from neglect of basic maintenance. We’ll answer some of your top questions:

  1. Why Is Your Engine’s Cooling System So Important?
  2. Engine Cooling System’s Main Components
  3. How Exactly Does Your Truck’s Engine Cooling System Work?
  4. Common Signs and Symptoms Your Cooling System May Need Maintenance
  5. Recommended Cooling System Brands, Parts & Tools  

Why Is Your Engine’s Cooling System So Important?

Simply put, your engine’s cooling system keeps the engine from overheating by the transfer of engine heat to the coolant and dissipated in exchange with moving air. If the cooling system fails in any way or is affected by poor maintenance, the result can be costly engine repairs and even disastrous engine replacement from extreme overheating. Even transmissions using the cooling loop from a radiator can be affected and sustain damage.

Five Essential Duties of Your Engine’s Cooling System

The primary duties of your heavy-duty cooling system are:

  1. Efficiently transfers engine heat
  2. Controls critical metal temperatures
  3. Increases the cooling index (helps prevent overheating failures)
  4. Provides protection against freezing.
  5. Inhibits rust and corrosion for cooling system metals

Engine Cooling System’s Main Components

The main two major components are the radiator and charge air cooler for the turbocharger. These two parts are vital to your engine’s overall cooling system. However, they would not be able to properly achieve all aspects of cooling and protecting your diesel engine without the following:

  • Radiator Caps
  • Hoses
  • Surge Tanks
  • Coolants
  • Oil Coolers

How Exactly Does Your Truck’s Engine Cooling System Work?

Basically, there are 2 means of dissipating engine generated heat. Air to liquid exchange and air-to-air exchange.

Air-to-Liquid Exchange

Your truck’s radiator is the integral component in this cooling process. Via an engine driven water pump, it circulates a coolant loop which supplies coolant to the engine and returns it back through the radiator. As the coolant flows through the fins and tubes inside the radiator, it transfers the heat from the coolant to the air. Once the excess heat is removed, the radiator then re-circulates the cooled coolant back through the engine chambers. This is an ongoing process of pushing cooled coolant from the radiator into the engine and taking the hot coolant from the engine and pumping it into the radiator. 

If the coolant levels or mixtures are not properly maintained, the engine may overheat. Serious and/or costly problems could develop. 

Air-to-Air Exchange

Instead of transferring heat via coolant, charge air coolers lower the engine’s temperature by transferring heat into the air. The charge air cooler, which is essentially an air-to-air heat exchanger, is designed for recirculating and cooling exhaust air along with ambient air back into the engine air intake system via a turbocharger.

Wheelco Quick Tip: When properly working, the charge air cooler cools the air from anywhere between 180°C to 220°C, down to around 40°C. 

Common Signs and Symptoms Your Cooling System May Need Maintenance

Like all wearable parts in your truck, the parts and components of your cooling system can eventually wear down.

Inspect your radiator if you see some of these common signs and/or symptoms: 

  • Leaking coolant which is dripping from a crack in your radiator or in your radiator hose. If you notice coolant under your truck or are constantly refilling your coolant, it is a sign that you have a leak. One of our service technicians/mechanics can perform a pressure test. This can help determine the source of the leak. We can repair the source of the leak.
  • Coolant Contamination: If rust is present in the radiator, it can cause significant damage to your engine block. Often when rust mixes with coolant, it becomes thick and sludge-like which can lead to engine corrosion. At Wheelco, we recommend flushing your radiator in order to remove all the contaminants.
  • Overheating: Over time, the radiator can become plugged by outside debris in the fins and also be affected by internal conditions such as coolant contamination and corrosion. If your radiator is working properly, the high temps could be a sign that your coolant package is exhausted, the engine thermostat has gone bad, or the water pump is not working properly.

Inspect your charge air cooler if you see some of these common signs and/or symptoms: 

  • Loss of engine power
  • Increased fuel consumption
  • Elevated coolant temperatures
  • Exhaust manifold failure
  • Premature piston, ring, and valve failure
  • Turbocharger failure
  • Increased particulate levels in emissions

At Wheelco, we suggest testing your charge air cooler if you notice signs and/or symptoms that your charge air cooler is failing.

Recommended Cooling System Brands, Parts & Tools 

At Wheelco, we recommend using Northern Radiator when you are looking to replace your cooling system components. These are the brands we trust if you are in the heavy-duty market for new cooling systems.

Charge Air Coolers

We recommend using Northern Radiator charge air coolers. They feature a two-year limited warranty, meet OEM specifications, feature a laser-scanned design, and are built brand new.  

Common part numbers for Northern Radiator’s Charge Air Coolers are:

There are multiple different core types available on the market. Learn more about their advantages and disadvantages with Northern Radiator’s CAC Core Types Guide


We recommend using Northern Radiator radiators. They feature a one-year limited warranty, have an all makes, all models coverage, meet OEM specifications, and are built to perform.  

Common part numbers for Northern Radiator’s radiators are:

Radiator Caps

You should replace your radiator cap as needed too. Common signs a radiator cap needs to be replaced include overheating the engine, overflowing reservoir, leaking coolant, collapsed radiator hose, or air bubbles in the cooling system.

Norther Radiator Cap

Common part numbers for Northern Radiator’s caps are:

Radiator Mounting Pad

If you need to replace your radiator mounting pad, we recommend using Northern Radiator (Part number: Z72009) for replacement on these Northern Freightliner radiators: 239137, 239138, 239139, 238603, 239326, 239368, 239013, 239285, 239336, 239117. 

Hydro Flush Gun

We recommend using Northern Radiator’s Hydro Flush Gun (Part number: RW0054-5) for cleaning your radiators and charge air coolers. It features a Pro-Tec cone nozzle and a heavy-duty squeeze trigger air valve with a molded handle. The 24” wand keeps water from spraying you as you clean. 

Charge Air Cooler Tester Kit

We recommend using Northern Radiators Charge Air Cooler Tester Kit (Part number: RW0090-11). The kit includes a set of 2 pads, regulator gauge, safety valve, and instructions. 

Still Have Questions or Need Help with Your Cooling System?

Questions? We can help? Are you looking to upgrade, replace, or service your heavy-duty engine cooling system? We can help you get the exact part you need. Our service technicians can provide service help on the diagnosis, part installation, maintenance work and/or repair jobs. Simply give us a call or stop by one of our stores today.

About Wheelco Truck & Trailer

At Wheelcobeing customer driven is more than just a motto we live by. It means that our employees will do everything we can to best serve you, our valued customer.

Customer driven is more than just offering you advice, giving time-honored service or contributing the latest tech-support. It’s about being there—whenever and wherever you need us—in-person, over the phone or online.

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