Preparing your truck’s HVAC for the summer
Have you ever had the pleasure of taking a long trip in the heart of summer without your trailer’s air conditioning working properly? Otherwise, let me tell you, it’s not fun and makes driving uncomfortable.
General maintenance work on a truck’s HVAC system is important to increase the life of AC parts and reduce the risk of downtime. To see if your truck’s AC unit is in good standing, you must first know the warning signs of failing parts, the common causes of a broken AC, and the main parts to fix it.
Warning: your AC is about to break down
Hot air blowing through the vents is a typical sign of a failing air conditioning system. The blast of hot air is often accompanied by a squeak, or even an unpleasant odor. These events are the most common warning signs of failing HVAC systems, but what causes them?
Hot air explosions – This could mean you have a failing condenser, evaporator, or AC compressor. Condensers convert gases to liquids and if they become clogged or blocked, they will not be able to operate as intended. “When the condenser fails, the heat doesn’t distribute properly and your unit only blows hot air,” says JIT Truck Parts blogger Jeremy Handel. The AC evaporator could also freeze. the AC evaporator is responsible for supplying cold air to the air conditioning systems, but if the evaporator coils leak, the cooling capacity is reduced and will blow hot air throughout the cabin. [Leaks are caused by corrosion inside the evaporator core or from damage to the outer seal on the evaporator core.] To finish, “compressors need to pump refrigerant to cool the air. If your compressor is not pumping refrigerant, it will only blow hot air. If poor airflow persists, replacement of these AC parts is required.
Rattling and squeaking noises – The origin of the squeaking depends on the type of air conditioning unit in the truck. Newer AC units usually don’t have fan belts. For older models that do, it’s best to check for slipped or misaligned belts on the engine that could be causing the squeal. The noise can also come from worn AC condenser bearings. AC condenser fans are attached to a motor which creates rotation. The bearings inside the motor often wear out over time, and when they do, they create a high-pitched noise. A build up of refrigerant pressure in the AC compressor can also cause unusual noises.
Bad smells – The environment can play an unpleasant role in why your air conditioner smells bad. Strange odors coming out of the vents can be from a buildup of debris, including mold and mildew growing in the evaporator. If the unit smells bad, you should quickly replace the evaporator coils and air filters so you don’t breathe in these contaminants.
AC Inspection Tips
Air conditioning compressors, evaporator coils, condensers, valves and filters will need to be inspected to ensure a cool ride during the summer.
To avoid problems, you’ll want to perform the following maintenance tasks:
• Refrigerant leaks from hoses, O-rings, compressors and evaporators are common reasons for failure of air conditioning systems. Remember to look under the vehicle for leaks and tighten hose connections to prevent leaks. Perform a dye test if you are unsure of the source of the leak. They are often used by professionals to check for leaks and can be done by applying a small amount to the refrigerant.
• You can recharge the system. If you are doing this task you will want to “locate and open the low pressure valve, then attach the refrigerant to the valve and charge from there. Be sure to use the correct type and amount of refrigerant as specified by the manufacturer. It is possible to overload AC power, so consider asking a mechanic for help.
• Check system sensors and broken switches. If the high pressure switch malfunctions, it could lead to airflow disturbances that will not be able to detect if the correct amount of refrigerant is flowing through the system.
• Failing expansion valves, orifice tubes and clutches can cause compressors to malfunction. Damaged hoses and seals can lead to problems with condensers. Do not neglect the inspection of other smaller parts.
When it’s 95°F outside, the last thing you want is for your truck’s air conditioning system to fail. Repair failing AC parts now to avoid uncomfortable long drives this summer.
Jennifer Smith is an e-commerce digital content specialist at JIT Truck Parts in Highland Park, Illinois.