July 20, 2023

Common Reefer Problems In Heavy-Duty Trucks And Trailers And How To Fix Them

Reefer systems ensure fresh cargo transport but can face issues. Learn common problems, diagnosis, prevention, and fixes in this article. Keep your cargo cool and business thriving!

Common Reefer Problems In Heavy-Duty Trucks And Trailers

Reefer systems are the backbone of transporting perishable goods all across the world, ensuring they reach their destination fresh and safe. However, like any complex machinery, reefers can encounter issues that lead to spoiled cargo, financial losses, and potential hazards. 

In this article, we'll explore common reefer problems for heavy-duty trucks and provide detailed insights on diagnosing, preventing, and fixing them. Let's dive in and keep your cargo cool and your business thriving!

Common Reefer Problems

Compressor Failures

Compressors are the heart of reefer systems, responsible for circulating refrigerant and maintaining desired temperatures. When a compressor fails, it can disrupt the cooling cycle, leading to cargo temperature fluctuations and potential spoilage.

Refrigerant Leaks

Refrigerant leaks can cause a drop in cooling efficiency and compromise the overall performance of the refrigerant unit. Not only do leaks affect cargo quality, but they also contribute to environmental concerns.

Temperature Fluctuations

Inconsistent temperature control can be a symptom of various reefer problems. Temperature fluctuations pose a risk of cargo spoilage or freezing, depending on the nature of the problem.

Defrosting Issues

Proper defrosting is crucial for optimal reefer performance. Failure to defrost the evaporator coil adequately can lead to ice buildup and reduced cooling efficiency.

Faulty Sensors

Temperature and pressure sensors are vital to maintaining the reefer's operating conditions. If these sensors are inaccurate or malfunctioning, they can lead to improper temperature settings and potentially damage the cargo.

Electrical Problems

Reefer units rely heavily on electrical systems for various functions. Electrical issues such as blown fuses, damaged wiring, or faulty relays can disrupt the reefer's operations and cause complete system failures.

Insufficient Cooling

Inadequate cooling can result from various factors, including low refrigerant levels, a malfunctioning expansion valve, or issues with the condenser.

Drainage Problems

Proper drainage is essential to remove condensation and excess water from the reefer system. Clogged or malfunctioning drainage channels can result in water buildup, leading to rust, corrosion, and potential damage to the unit.

Fuel System Issues

Some reefer units are powered by the truck's fuel supply. Problems with the fuel system, such as clogged filters or faulty injectors, can impact the reefer's performance and cause irregular cooling.

Belt and Hose Failures

The reefer system's belts and hoses are critical for the circulation of refrigerant and the operation of various components. Wear and tear or damaged belts and hoses can lead to system malfunctions and reduced cooling efficiency.

Causes and Prevention

Understanding the potential causes of reefer problems is key to preventing them in the first place.  Here are some preventive tips:

Scheduled Maintenance: Set up a regular maintenance schedule with professional mechanics like ours at Fleetmaster Truck and Trailer Repair to inspect and service your reefer units.

Check Refrigerant Levels: Monitor refrigerant levels and address any leaks promptly to maintain cooling efficiency.

Electrical System Inspection: Regularly inspect the electrical components and connections to detect and fix potential issues.

Defrost Cycle Monitoring: Ensure the defrost cycle works correctly to prevent ice buildup and preserve cooling capacity.

Temperature Calibration: Regularly calibrate temperature sensors and thermostats to ensure accurate temperature control.

Inspect Belts and Hoses: Check belts and hoses for signs of wear or damage and replace them as needed to avoid system failures.

Proper Loading: Ensure cargo is loaded correctly to allow proper airflow within the reefer unit.

Clean Condenser and Evaporator: Regularly clean the condenser and evaporator coils to maintain optimal heat exchange.

Troubleshooting and Diagnosis

Being able to understand when reefer components are failing is key to preventing them from developing into more serious issues. If you notice any of these, visit our team at Fleetmaster Truck and Trailer Repair immediately: 

Compressor Failure: If the reefer is not cooling, check for unusual noises from the compressor or warm air coming from the unit. 

Refrigerant Leaks: Look for visible signs of refrigerant leaks, such as oil spots or greasy residue around the unit. 

Temperature Fluctuations: Monitor the temperature readings over time. If there are significant fluctuations, a professional inspection of the temperature sensors and thermostat is needed.

Defrosting Problems: If the unit is not defrosting correctly, check the defrost timer and heating elements. 

Electrical Issues: If the reefer is not powering on or showing error codes, check for blown fuses and loose connections that will need to be replaced.

Insufficient Cooling: If the cargo is not cooling adequately, check the refrigerant levels and the condenser's condition.

Drainage Problems: Inspect the drainage channels for clogs and debris, ensuring proper water flow.

Fuel System Check: If the reefer is fuel-powered, inspect the fuel system for clogs or fuel delivery issues.

How to Fix Common Reefer Problems

While some reefer problems may be simple to fix, others require professional expertise. Here are some step-by-step instructions for common issues:

Replacing a Faulty Compressor

  1. Disconnect the power supply and refrigerant lines
  2. Remove the old compressor from its mounting
  3. Install the new compressor and connect the refrigerant lines securely
  4. Reconnect the power supply and test the reefer for proper cooling

Repairing Refrigerant Leaks

  1. Locate the source of the leak using a refrigerant leak detector
  2. Remove damaged or leaking components, such as O-rings or fittings
  3. Replace the faulty parts and ensure a proper seal to prevent future leaks
  4. Recharge the refrigerant to the correct levels

Adjusting Temperature Settings

  1. Refer to the reefer unit's manual to locate the temperature controls
  2. Calibrate the temperature settings according to the cargo requirements
  3. Monitor the reefer unit to ensure the desired temperature is maintained

Fixing Defrosting Issues

  1. Check the defrost timer and heating elements for proper functionality
  2. Replace faulty components if necessary, or seek professional help for repairs

Checking and Replacing Faulty Sensors

  1. Identify the faulty sensor using diagnostic tools or error codes
  2. Replace the sensor with a new one that matches the specifications

Addressing Electrical Problems

  1. Locate the blown fuse or faulty relay in the electrical panel
  2. Replace the blown fuse or relay with a new one of the same rating
  3. Secure any loose electrical connections to restore proper functioning

Clearing Drainage Channels

  1. Inspect the drainage channels for clogs or debris
  2. Use compressed air or a soft brush to clear any blockages

Cleaning the Condenser and Evaporator

  1. Disconnect the power supply and remove the protective panels
  2. Use a soft brush or compressed air to clean the condenser and evaporator coils
  3. Reinstall the protective panels and reconnect the power supply

Addressing Fuel System Issues

  1. Inspect the fuel lines, filters, and injectors for clogs or damage
  2. Replace any faulty components or seek professional help for repairs


Ensuring that your reefer units are in top condition is essential for the successful transportation of perishable goods. By familiarizing yourself with common reefer problems and following preventive measures, you can reduce the risk of disruptions and costly cargo losses. 

At Fleetmaster Truck and Trailer Repair, we have the expertise and experience to handle all your reefer maintenance and repair needs. Just pick up the phone and get in touch with our experienced team today!