In addition to hot systems being a safety concern, coolant should always be drained into a suitable container when it is removed from the engine for maintenance or repair. Used coolant should also be disposed of in a proper and legal manner. Many parts stores allow customers to bring in used fluids to be recycled. The store will typically record the names of people who bring in used fluids. Coolant should never be poured out on the ground or into a drain that connects to public sewer systems.
It is vital to use confident actions when connecting and disconnecting service hoses to the service ports on the AC system. The valve should also be in the released position when connecting and disconnecting it from the system.
Refrigerant should only be stored in areas that are free from direct sunlight or added heat. The pressurized refrigerant should also be stored away from areas where lots of movement and sharp objects are present to prevent one of the containers from being punctured.
A reliable drain pan should be placed under the drain valve when releasing coolant from the radiator. There is typically an open path for the draining coolant to reach the pan without running down the frame, but care should be taken to catch as much of the draining coolant as possible.
Belts
The drive belts on an engine are an area where caution must be used in order to prevent injuries when working on the AC system. Many drive belts on late-model vehicles are held in place by a spring-loaded tensioner that holds strong pressure on the belt at all times. The belt tensioner must be released with the proper tool to safely remove or install the drive belt.
Drive belts on older vehicles are typically a V-belt type and are adjusted by moving one of the accessories on a pivot to allow the belt to be loosened or tightened. The key point to remember when dealing with adjustable V-belts is to tighten the belt to the correct level but not overtighten it. Overtightening these belts adds stress on the pulley and bearing of the accessories and could lead to early failure. It is also a prudent action to recheck and possibly adjust the belt tension on brand-new V-belts after they have been installed for a few days.
V-belts are used on older-generation cars and trucks. These belts are adjusted by physically moving one of the driven components within an open groove in the mounting brackets or by installing an adjustment strut that allows the belt tension to be adjusted by shortening or lengthening the bar.
The accessories on most late-model vehicles are driven by a serpentine belt that is much wider than the belts on older vehicles. This belt system typically uses a spring-loaded tensioner that holds constant pressure on the belt during operation.
The belt tensioner on a serpentine belt must be released when removing or installing the drive belt. Some vehicles allow a ratchet or a socket to be used to release the belt tensioner, while other vehicles require a special belt-release tool to be used to service the drive belt.
A belt tension gauge is a valuable tool to use when installing a new V-belt or when adjusting the tension on a used V-belt. After this tool is inserted on a section of the belt, it measures the deflection of the belt and lets the user know if the tension is correct. If the tension is too loose, then the belt can be tightened up. If the tension is too tight, then the belt can be loosened.
Electrical System
The vehicle’s battery and electrical systems must be respected when working on the air-conditioning system. Disconnect the battery prior to performing work under the dash, such as replacing the heater core or the evaporator core. Repairing the HVAC system often requires electronic components to be disconnected, so this process should be handled carefully.
Airbags
All modern-era vehicles have airbags located on the steering wheel and passenger-side dash panel. In addition, airbag assemblies are also found in the side pillars, seats, and doors of many late-model vehicles. Extreme caution must be used when performing diagnosis and repair inside the vehicle and under the dash area. The first step that should be taken prior to performing extensive disassembly of the instrument panel is to disconnect the battery negative cable and secure it with a shop towel or similar item to prevent the cable from moving back into contact with the battery terminal. After removing an airbag assembly, it should be handled carefully and stored in a safe place facing upward to prevent the unit from being projected in case of an inadvertent deployment.
The negative battery cable should be removed and secured prior to performing extensive repairs on the AC or heating system. Having the power removed from the vehicle reduces the chance of shorting out a live circuit when performing repair work.
Extra caution should be used when connecting and disconnecting electrical connectors on cars and trucks. Most connectors have locking tangs that must be carefully released when disconnecting the device or module.
All modern vehicles are equipped with an airbag assembly that is mounted directly in front of the driver in the steering wheel. Care must be taken when working around the driver-side airbag assembly to prevent accidental deployment during service of the AC and heating system.
Passenger-side airbags are available on most late-model vehicles and must be carefully handled when working around the dash panel assembly. Yellow wire covering is used on most of the circuits that are used in airbag systems.
Airbag assemblies should be handled in a very careful manner by using a secure grip with both hands. The top of the airbag should be facing away from the body to add another layer of protection in case of accidental deployment.
Airbag assemblies being stored during a repair process should be kept in a safe place facing upward. This prevents the airbag from becoming a projectile if the airbag accidentally deploys.
Legal Issues
There are a variety of laws that must be followed when working on the HVAC system on a vehicle. The item that comes to the forefront is allowing refrigerant to be vented into the atmosphere. It is against the law to willfully allow refrigerant to be released from a vehicle’s AC system or from a container. Care should be taken to prevent the loss of refrigerant during any process being performed on the vehicle. In addition to not venting refrigerant, the lubricant for the AC system should be collected and stored in a safe container. The oil can be collected by a reputable company and disposed of