Properly functioning air conditioning is about safety as well as comfort
By Homer Hogg, Senior Technical Trainer for TA and Petro
It’s hot! And in some cities, it’s hot and sticky. If you find yourself saying, “Please let my air conditioning system work today!” then you need to continue reading for tips on keeping your AC system in optimal condition.
Parts to watch
The principle of air conditioning is not new. Ancient Rome’s aqueduct system circulated water through the walls of some houses to cool them. Modern AC is more complicated, and key components — condenser, evaporator and AC clutch air gap — must be monitored and serviced when necessary.
The condenser and evaporator are the heart and soul of your AC system. The evaporator transfers the heat load from the cab to the refrigerant. Then the refrigerant takes the heat to the condenser and releases it to the atmosphere. Both must work correctly to be effective.
Keep a close eye on your condenser, which is mounted in front of your radiator. Look closely at the condition of the fins. A truck’s condenser fins are vulnerable to a variety of elements. They can get damaged by road debris and poor service techniques. It is imperative that you take a fin comb and straighten the fins as soon as you see damage. If they remain bent, the performance of your system will be negatively impacted, resulting in compressor damage due to the condenser’s inability to exchange the heat load.
It is equally important to keep the condenser clean. A dirty condenser cannot properly remove the heat necessary to keep your AC system operating at an optimal level, especially when it is near 100 degrees outside.
The evaporator inside the cab or inside the evaporator box is out-of-sight and so sometimes out-of-mind. Though the condition of the evaporator is typically near impossible to see, most manufacturers install a filter that must be serviced. The cabin filter is usually located in the engine compartment on the passenger side or inside the cab on the lower right-hand side. This filter must be checked regularly and replaced when needed. If you operate in a dusty climate, the filter may need to be serviced a couple of times a year. The cabin filter not only ensures good air flow from the vents but also keeps the cab air clean from mold and bacteria. So stay comfortable and keep your lungs healthy by servicing the filter on a regular basis.
Too big to let fail
Modern compressors are durable and very expensive, yet more than 60 percent of all AC failures are compressor-related. The No. 1 cause of that failure is heat generation due to maintenance neglect. A worn-out belt tensioner or pulley, contaminated belt or worn-out belt can slip, causing heat to migrate to the front seal and front mechanical components of the AC compressor. Low refrigerant levels decrease the cooling function necessary to keep the compressor operating at its peak. A dirty condenser traps heat in the system, causing the compressor to work harder, which shortens its life. Finally, the clutch air gap should be checked periodically and adjusted to prevent slipping, which will result in compressor failure.
Keep your cool
The need to maintain a pleasant climate inside the cab is more than a simple creature comfort. It’s actually critical to ensuring that you stay alert and ready to react to any emergency situation that may arise.
If you stay on top of a few basic service requirements such as belt condition, cabin filter and condenser cleanliness, refrigerant level maintenance and the compressor clutch air gap adjustments as needed, your vehicle’s AC system should help keep you cool for years to come.
Homer Hogg, Senior Technical Trainer for TA and Petro, has worked as a truck technician for 30 years. He is ASE-certified, a Daimler Certified Trainer and a member of the Nashville Auto Diesel College Hall of Fame.
Homer Hogg’s “Maintenance Matters” airs on the Dave Nemo Show (Road Dog Trucking, SiriusXM 106), 8 a.m. ET, the first Thursday of each month.