Common Causes of Vehicle Air Conditioning Failure and How to Avoid Them

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vehicle air conditioning repair

Without air conditioning, a car may easily reach temperatures of 150 degrees or higher on a hot summer day, making it a miserable place to be stuck. However, air conditioning is about more than just convenience. Indeed, since temperatures inside a car without air conditioning may rise to potentially lethal levels during a heat wave, it is one of the most dangerous places for a person to be.

If the air conditioner in your car is not cooling the interior, you should take urgent action to have the problem rectified.

Before taking your unit in for professional vehicle air conditioning repair, here is a rundown of the most typical AC problems, along with some suggested DIY repair or diagnosis solutions

AC Isn’t Blowing Cold Air

A refrigerant leak is typically the root cause of this problem. The refrigerant is crucial to the operation of your air conditioner. The other parts of the AC system will only work if there is enough refrigerant.

Leaks can happen anytime but typically result from damage to the evaporator, compressor, condenser, or hoses. Unfortunately, unlike an oil leak, spotting a refrigerant leak can be tricky. Because its very nature is to evaporate when exposed to air, the refrigerant has this effect.

Solution: A professional vehicle mechanic should inject refrigerant and fluorescent leak tracer dye into the system. Once the refrigerant has been injected, the technician can turn on the air conditioner, use a black light to locate the leak, make repairs, and then execute an evacuation and recharge so that cold air can be produced again.

The air is cool without actually being frigid

The most prevalent reason for this is low levels of refrigerant. Reduced pressure caused by insufficient refrigerant prevents the clutch from engaging the compressor’s rotating shaft—the presence of sufficient refrigerant in the system.

The condenser, which removes heat from the gaseous refrigerant and converts it back into a liquid, may be clogged or have failed. The air flowing out of the vents won’t be cool if the condenser is clogged or broken.

Failure of the clutch switch prevents the air compressor from running, which prevents the liquid refrigerant from being condensed into gas.

Solution: A professional should check these major components for obstructions, damage, or failure and, if necessary, their place.

AC Has a Mildew Scent

The growth of bacteria in an air conditioner’s system is the source of the unpleasant mildew odour it can produce when turned on. When the air conditioner is rarely used, when the car is older, or when the maximum setting is routinely used, condensation can form inside the unit. Bacteria, fungi, mould, and other microbes thrive on the evaporator, which is located behind the dashboard. The vents stink due to the vegetation blocking them.

Solution: Eventually, air filters might stink from collecting dirt, water, dust, and other contaminants. Changing the air filter will help alleviate this problem. If changing the filter doesn’t solve the problem, a technician must spray mould and other impurities down the drain in the evaporator area with an anti-bacterial solution.

The roar of an air conditioner in a car

Any time your car starts making a noise it didn’t produce previously, you should take notice. When in use, air conditioners don’t make a lot of noise. Feeling anxious when you turn on your air conditioner and hear rattling, pounding, or other strange sounds is normal. Leaves and other road debris can clog the device and cause it to make strange noises.

It’s also possible that this is a sign of a significant component failing. The air conditioner will make a grinding or screeching noise if a bearing is worn out. The clutch may have worn out if the compressor starts making rattling noises.

Solution: Using the air conditioner further may exacerbate the problem. Have a trustworthy mechanic have a look at your vehicle. If a significant component is failing and has to be replaced, this can be determined with a comprehensive inspection for reliable auto parts.

Standing Water on the Floor

The evaporator coil in the air conditioner’s heating box, housed under the dashboard, might become contaminated with bacteria over time. Condensation from the coils combines with airborne germs to form a slimy film on the air conditioner’s fins, which gives off a musty odour.

The accumulation of film over time might cause a clogged drain. The evaporator heater box is where the rubber drain line begins its journey down through the floor and into the undercarriage. Water from condensation fills the heater box and drips out, usually onto the passenger side floor, until the box is unplugged.

Solution: There’s no time to waste if you notice water on the floor of your automobile; get it checked out right away. A specialist must inspect the clogged drain line and make the necessary repairs or replacements.


Proper car AC maintenance and a clean interior atmosphere necessitate a regularly cleaned air conditioner. The air conditioner in your car requires little upkeep. With some TLC, you may avoid a costly visit to the mechanic and keep it running smoothly for a long time.