The transformation often takes place gradually. The donning of sunglasses as the morning light glares above the horizon. Jackets hang ever longer on the coat rack. Snow melts and mud begins to dry. Spring has arrived and summer is nearly upon us. While the warmer weather is most likely a welcome relief for cold fingers and toes, it places fresh demands on vehicle systems previously coping with the cold.

For instance, the HVAC system is switching roles. Throughout the winter, the HVAC system has hopefully fulfilled the expectations of keeping the vehicle interior warm and comfortable, the windows defrosted, and the air fresh and clean. With warmer weather emerging, the HVAC sub-systems and components that helped keep the cold at bay need some attention. Here are some tips to keep the system in peak performance:

• Inspect the heater, bypass and radiator hoses for seepage, stiffness or cracking, oil leak damage or any damaged resulting from rubbing against another component.
• Inspect drive belts for wear or damage.
• Inspect the A/C compressor, lines, and hoses for leaks or damage.
• Inspect mountings for damage as well as loose or missing mounting fasteners.

There are a few more HVAC areas that may be overlooked at times, but need attention to keep the system operating in top shape. These include:

• Inspect the condenser for debris blocking air flow. Dirt, leaves and other junk blocking the airflow through the condenser reduces the efficiency of the air conditioner. In addition, make sure the condenser fins are not bent to the point of blocking air flow.
• Inspect the HVAC drains to be sure they are clear and allow condensation to drain. Drains that are not working properly could result in some, hopefully unwelcome, cab interior scents.
• Inspect the cabin air filter, if equipped. As Spring emerges, critters tend to look for new places to establish a nice warm and comfortable home. The piping and cabin filter housing makes for an ideal home. Even if the mice and rats have not moved into the neighborhood, the filter still needs to be inspected and replaced if needed as the pollen and dust connected with Spring and Summer emerge. 
• Inspect the electrical wiring and connectors for damage. If connector locks are broken the connections could work loose causing an intermittent condition.

Once these preliminary inspections are performed and problems corrected, the system operation and charge can be checked. Keeping the HVAC system in good working order helps keep the truck on the road and provides driver comfort.

While the HVAC system likely goes unnoticed when operating correctly, it becomes the center of attention when it fails to perform. Comfort may be taken for granted, but it takes a little effort to stay that way.   

Additional tips for repair and maintenance of Class 4-8 trucks may be found in the Mitchell 1 ShopConnection Truck blog.