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7123 Tazewell Pike

Corryton, TN 37721



(865) 689-5072

FAX: (865) 689-7765



Tips For Auto Air Conditioner Maintenance

May 9, 2023 | auto repair

Auto maintenance

Auto maintenanceWhat you can do and what should be left to a trained professional when it comes to car air conditioner maintenance? Humidity can be unbearable in some states, vehicle air conditioners are a must. Most people with some mechanical knowledge can perform a few simple visual checks and manual procedures. You can be confident that your air conditioner will handle the summer heat by doing a few simple things.

Auto Maintenance Tips

Checking the A/C system & keeping it running

In the months when air conditioning is not available, it’s important to run the air conditioning system in vehicles that operate in colder climates for ten minutes every week. The oil will be circulated in the system and the seals will remain lubricated, preventing Freon from leaking out. The air chambers will be dried out by running the air conditioner regularly. This reduces the chance of mold and fungus growing, which can cause unpleasant odors.

You should also check for any auto air conditioner problems. It is easy to do. Our first step is to inspect the A/C Condenser, located just in front of your radiator. Freon turns from a gas to a liquid in the condenser. The condenser must be clear of any obstructions that could restrict air flow, like a bug screen. The efficiency of your car’s air conditioner will decrease if the condenser becomes blocked. Condenser cleaning is easy with a garden hose fitted with a high-pressure nozzle.

Checking the Engine Fan and Fan Belt

Next, we will check the engine fan. It can either be electrical or mechanical. When the air conditioner is on, the electric fan that’s mounted to the radiator must be running. The absence of the fan can cause excessive pressure to build up in the system. This can lead to the rupture of the hoses and loss of Freon or oil. One of the two fans in some systems is required to run when the air conditioner system is turned on. When you drive your car and notice that the air from the ducts is cool but the temperature rises when the engine is idle, the cooling fan may not be working.

When the air passes through the condenser, and the radiator is heated, the fan clutch should tighten and start spinning faster. You can quickly test the clutch by performing a simple test. Turn the fan manually while the engine is cold and the ignition is off. It should be able to spin freely, which is what it should do. You should be able to feel resistance when you rotate the fan. It is likely that you have a defective clutch fan if it spins freely and is loose when the engine heats up. If the air from the ducts in your vehicle is cold while driving, but becomes warmer when you are idling, then it is likely that the clutch fan is defective.

The next step is to visually inspect the fan belt. Check the belt’s underside for cracks. The belt should be changed if cracks are discovered. When replacing the belt on older vehicles, you will need a belt tensioner to avoid excessive pressure being applied to the components driven by the belt. It can lead to premature failure of the driven items. However, this is not an issue with modern vehicles that have a belt tensioner.

Checking the Operation

We will now check the performance of the air conditioner. Start the engine, and set the temperature control to the coldest setting. Set the fan speed switch to the highest setting. A clutch is located on the front of the compressor to engage the internal components. You should be able to see the clutch and the drive pulley moving together if you look at the air conditioner compressor. Normal is that the clutch will turn on and off every 20-30 seconds. The clutch will cycle on and off every few seconds if the system has low Freon.

Auto maintenanceWhy You Need A Professional

In a single year, air conditioning systems can lose between 10% and 15% of Freon. You will need the help of a professional car air conditioner maintenance Knoxville TN to do this. Each air conditioning system is designed to have a specific amount of Freon. There is usually a label on top of the radiator, under the hood, or in the chamber that holds the system evaporator. This tag will list the amount and type of Freon (in pounds and ounces) that is required to operate the system properly and efficiently. You can often see a leakage area because the Freon also leaks oil. Leakage can be detected by oily or dark residues on fittings and hoses. Leaks can also be found by using a dye that detects leaks or an electronic detector.

It is not a good idea to add Freon to a system that is low. It is impossible to know how much Freon a system contains. If you add too much, you risk damaging the compressor and creating high pressures that can lead to hoses bursting. It is best to start over by completely removing the air conditioner and adding the exact amount of Freon listed on the tag. To perform the recharging process, you will need a set of air conditioner gauges and a vacuum. When you apply more than 17 inches to a system, moisture will be removed because water boils when 17 inches are applied at sea level. To ensure that all moisture is removed, the vacuum pump should remain on for at least 20-30 minutes. The low-pressure gauge has a vacuum side so that you can see how much vacuum is applied. Both gauges will be turned off after 20-30 minutes to allow the technician to observe the vacuum side. Wait about five minutes and check if the vacuum has decreased. If the system has a vacuum, it should also have Freon.

How to Recharge Your Own Devices?

Avoid the DIY recharge kits available at most parts stores. Remember that an inoperative air conditioner could be caused by other factors than the loss of Freon. What if the problem was caused by something other than low Freon? When Freon is added to a system that’s already full, the liquid Freon can destroy the compressor or cause the hoses to burst. All of this is bad.

When working on air conditioning systems, extreme caution is required. Wear safety glasses at all times. If a line bursts and Freon gets into your eyes, it can cause them to freeze instantly and even lead to blindness. These kits should only be handled by professionals. Too much oil will decrease the efficiency of your unit. It is not necessary to add oil unless the system components need replacing.

What Does Dripping Water Mean?

You will see water dripping under your vehicle when the air conditioning is working. It is normal for the condensation to come off the evaporator that has been removed from inside the vehicle. This is an indicator that the condensation drains are plugged in if you see water on the passenger-side floor and not underneath the vehicle. Over time, fungus or mold can develop in the water and plug the drain port. This will most likely need to be cleaned from the underside.

The last and most frequent question I receive is “Why doesn’t the air get cold quickly?” There are several reasons why the air conditioner is not working properly. The first one is the heat from the dash. The dash will cool down in a few moments. A system will also be more efficient if the humidity in the vehicle is removed. It takes a couple of minutes to do this, and you can also see the moisture dripping from the vehicle’s underside. Most newer cars have a cabin filter that, when blocked, will reduce the airflow from the dashboard. This filter needs to be replaced a few times a year.

Before the summer heat, when auto shops are busy, it is a good idea to service and inspect your system. When people are overheated, they tend to spend more than necessary. Shops that claim Freon is worn out and must be replaced are misleading. Many quick-lube shops also promote recharging the air conditioner as an easy, profitable upsell. It is likely that they will just add Freon, and not perform a proper recharge procedure described in this article.

Call Miller Brothers Transmission Auto Repair and Body Shop now if you need to have your car’s air conditioning checked, maintained, or repaired.

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Miller Brothers Transmission Auto Repair and Body Shop
7123 Tazewell Pike
Corryton, TN 37721
(865) 689-5072

Serving Knoxville, TN and Knox County

Service areas include: All of Knox County, Corryton, Fountain City, Halls Crossroads, Powell and Knoxville


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Monday-Friday 8:00am – 5:30pm

Saturday 8:00am – 12:30pm


Phone: (865) 689-5072

Email: millerbrothers06@comcast.net

Miller Brothers Auto Repair
7123 Tazewell Pike
Corryton, TN 37721