The HVAC or Heating, Ventilation and Air Conditioning system in your car is a crucial installation. It helps you control your car's interior as part of your comfort while driving. It makes it easier to withstand the extremities of weather when driving. Whether you're having fun during the hottest part of summer when everyone is sweating or fighting your way through the dead of winter, a properly maintained HVAC system can make the difference in your comfort. And it makes all the sense in the world to be comfortable when you're working. Regular maintenance also saves you money on repairs. In this article, I bring you the steps required to maintain your car HVAC system and ensure that you are as comfortable as you need to be while driving.
- Understanding Your Car’s HVAC System
Components of the HVAC System
The system in your car consists of the following main components that work together to maintain the intempidity and the quality of the air in the car cabin:
Compressor: Pumps refrigerant through the air conditioning system, allowing it to cool the air.
Condenser: Heat is released by the refrigerant that’s been compressed and is now cooled, before being sent into the evaporator.
Evaporator: Absorbs heat from the cabin air, cooling it down and removing moisture.
Blower Motor: Circulates the air through the HVAC system and into the cabin.
Heater Core: Transfers heat from the engine coolant to warm the air.
Cabin Air Filter: helps filter dust, pollen and other contaminants from the air entering the cabin.
How the HVAC System Works
The HVAC system manages the flow through these components. In cooling mode, it removes heat from the cabin air passing through the evaporator, while the condenser dissipates the absorbed heat to ambient enviroments outside of the vehicle. In heating mode, the heat within the engine is pumped into the cabin through the heater core (that heats this air prior to its distribution to the inside by the blower motor), while clean air passes through the cabin air filter prior to being spread within the inside of the vehicle.
- Regular Maintenance Tasks
- Replace the Cabin Air Filter
The cabin air filter keeps dust, pollen, and other contaminants from the outside air that is brought into your car’s interior. If the filter is clogged, airflow will decrease and the HVAC system’s effectiveness will be reduced. Over time, your cabin air filter could block fresh air and create odours that may not be pleasant.
Steps to Replace:
Find the Cabin Air Filter: The Cabin Air Filter is under the glove box, or overhead next to the windshield.
- Remove Old Filter: Pull out old filter as you would any other filter from your furnace, or hold it up to feel the wind direction.
Here’s the new Filter: To install, turn light off and screw in the new filter in the same orientation as the old one: Make sure that it’s seated properly.
Putting (Back) the Cover: Put the cover in place and arrange the glove compartment or dashboard panel in its original state.
- Check and Recharge the Refrigerant
The refrigerant is the fluid that's actually cooling the air in your car's A/C. Refrigerant levels will go down over time due to leaks or normal use, hence the need to check and recharge.
Steps to Check and Recharge:
Check the Pressure: some refrigerant pressure gasses. Check the low and high side pressure. If the lowside is low, the system has lost freon.
Recharge System: Add correct the refrigerant type for the air conditioner system according to the recharge kit instructions. Don’t overcharge.
Check for Leaks: If the refrigerant level is repeatedly too low, search for leaks in the system. A leak detection kit can pinpoint and repair the leaks.
- Inspect and Clean the Condenser
The condenser is usually found at the front of the car, often behind the grille. It is part of the air conditioning system and gets rid of the heat that the refrigerant has picked up. The condenser can get clogged with grime, leaves and other dirt over time.
Steps to Inspect and Clean:
Visual Inspection: Look for any visible debris or damage to the condenser.
Clean the Condenser: You can use the hose or a specialised condenser cleaner spray to flush out dirt and debris from the fins of the condenser. Do not use the pressure washer, as that can damage the fins.
Damage: Check the fins for damage. Bend them back into place with a fin comb if they’re bent.
- Test the Blower Motor
Steps to Test:
Listen For Strange Noises: When you turn on your HVAC system, listen for unusual noises from your blower motor. Do you hear any squeaking or even grinding noises? If so, your motor — and possibly your fan — could be affecting the overall cooling capacity of your appliance.
Check Airflow: Set a digital scale on a stable counter or shelf. Place a piece of cardboard atop the scale. Turn on a fan at the highest and lowest speeds, and listen for the sound of air passing over the cardboard. If the sound is weak or inconsistent, the blower motor might be failing or a vent might be blocked.
Check the Motor: If one is found, visually inspect the blower motor and all attachments. Replace the motor or have it serviced by a specialist if appropriate.
- Maintain the Heater Core
Also known as a heater matrix, this small radiator is used to circulate the engine coolant, in order to heat the air blown into the passenger compartment via the vehicle’s blower motor. It can become plugged with debris over time, or a leak can develop, leading to a dramatic reduction in the heating efficiency, or even a coolant leak into the compartment.
Steps to Maintain:
Check for Coolant Leaks: Look for puddles of coolant (a mixture of water, engine antifreeze, various corrosion inhibitors and small amounts of metal particles) under the floor of the passenger compartment or a sweet, sickly smell in the cabin.
Flush The Heater Core: a ‘plugged’ heater core can be caused by corrosion. To fix the problem, the core can be flushed of any pluggage by running blown water mixed with some coolant.
Check coolant levels: Check the high and low indicator marks on the side of your car’s radiator and fill it only to the high mark. Then check the overflow tank (the clear plastic bottle with a rubber pipe going back into the radiator). The coolant level should be between the low and high marks and, if not, add more coolant (which you can buy in pound shops, supermarkets or garages) and check again until it is. This is particularly important if your heater isn’t working.
- Seasonal HVAC System Checks
- Pre-Summer Inspection
To make sure you won’t suffer any broken highs during peak summer temperatures, it’s important to have your air conditioning system checked now, during pre-summer months, so that you don’t get an unwanted surprise when you need your AC the most.
Checklist:
Check Refrigerant Levels Make sure the refrigerant charge is full and the system is not leaking.
Look at the Condenser: Clean the condenser and look for parts that might hinder air flow.
Test the AC Performance: 5-10 minutes after I start running the air conditioning I make notes about the cooling performance or airflow.
- Pre-Winter Inspection
When winter is coming, as Jon Snow said, you’ll need the heating of your vehicle to be in good shape so it won’t let you down in cold weather. Have a pre-winter check-up on your heating system to make sure everything is ready to work in cold conditions.
Checklist:
Run the heater – check to see if there is adequate heat output and airflow.
Coolant: Check Coolant (Photo courtesy of FOX)The coolant should be topped off and the mixture should be sufficiently diluted by antifreeze.
Check Heater Core: Look for leaks or blockages that might prevent the interior from heating.
- Recognizing Common HVAC Problems
- Weak Airflow
A weak airflow may have various potential causes, such as a clogged cabin air filter, a malfunctioning blower motor, or blocked air passages.
Solutions:
Replace the Cabin Air Filter: A dirty or clogged filter can significantly reduce airflow.
If the motor clutch isn’t engaged, the blower motor and fan will not work. In some rare circumstances, the fan blade might be jammed in the housing. Cleaning the Blower: Begin by removing the blower cover, which can be done by undoing three screws located on the switch housing. Note that the location of the access screws varies on different blower switch designs. Next, disconnect the wiring provided from the OEM blower motor and disconnect the electrical connector. The blower motor will then be visible.
Inspect Air Passages: Check vents or ducts for any obstructions that may be impeding air flow.
- Unpleasant Odors
One of the most common reasons for experiencing foul odours in the HVAC system is mould or mildew growth within the evaporator or air ducts. This is a result of moisture being retained in the system, allowing mould to soak up and thrive in these environments.
Solutions:
Run an HVAC Cleaner: Run a special HVAC cleaner or disinfectant through the evaporator and air ducts to kill mould and mildew.
Run Fan After Use of AC: After turning off the air conditioner, run the fan for a few minutes to dry out the evaporator, allowing the AC to begin again without the excess moisture.
Replace the Cabin Air Filter: If mould or mildew are discovered on a filter, replace it with a new one.
- AC Not Cooling
If your air-conditioning system is not cooling the cab as it should, you might have a low refrigerant level, a faulty compressor, or a congested condenser.
Solutions:
Refrigerant Levels: Too low and your system won’t provide adequate cooling. Make sure your system is fully recharged with refrigerant.
Check the Compressor: Make sure the compressor is properly working and also the clutch is acting.
Clean Condenser: If condenser get blocked, the efficiency of the AC will be reduced. Clean the condenser. Also remove any debris.
- Heater Not Warming
If your heater isn’t blowing enough hot air, perhaps there is a clogged heater core, low coolant liquid levels, or broken thermostat.
Solutions:
Flush the Heater Core: If the heater is clogged with rust, then by flushing the heater core, the heat transfers to the exterior.
Check Coolant Level: Low coolant doesn’t allow the heater to warm up the cabin. If necessary, add coolant.
Check the thermostat: If the thermostat is sticking, the engine will not reach operating temperature, which means less power to the engine and a less effective he
- When to Seek Professional Help
Their handiness comes in handy when it comes to basic HVAC maintenance. And car owners can certainly fix many issues on their own. But driving is all about safety, so consider bringing your car to a pro if you are experiencing any of the following problems:
System Leaks: System leaking can be an indication of a larger issue that the trained eyes of an expert need to diagnose.
Electrical Problems: HVAC controls can go out if there is electrical trouble with the thermostat, or if another electrical fault is encountered; these issues need to be addressed by a professional service call.
Strange sounds: Grinding, squealing, or other strange sounds could indicate a blower motor, compressor, or another part of the HVAC is having an issue.
Conclusion
It is great to have air conditioning in your car, but to keep it providing the comfort that you expect, particularly during the hot days of summer and the cold days of winter, your HVAC system should be maintained at least once a year. One of the best ways of HVAC maintenance is to replace the cabin air filter in your system. Check the refrigerant contents, blower motor, condenser, and other essential components of your HVAC system. If you notice any abnormalities, take your car for HVAC repairs. Pay attention to signs of common HVAC problems, and keep your car’s interior comfortable.