It’s that time of year: sweltering heat accompanied by congested commuter and vacation roads. And just when you need your air conditioning the most, all you get is hot air from the dash vents. Before you blow your own thermometer, here’s a little primer on how vehicle air conditioning systems work and why they most commonly fail. Your chariot’s AC system is made up of a dozen or so components that must be in airtight condition in order for the system to work effectively. The most common reason for lack of cool air is a leak of the refrigerant gas through any number of hoses, seals, gaskets or heat exchangers (commonly referred to as condensers). Just about all automakers cover these systems for the term of the base warranty of the vehicle (usually three years or 60,000 km, whichever comes first). The big exception is a leak caused by any type of collision or impact. If you bring your new ride into your dealership’s service department with a stone impact to the condenser, don’t expect warranty coverage.

Also read: Think twice before repairing that broken air conditioner Doing a little DIY diagnosis might give you an idea what you’re in for, before you take the vehicle into the shop. With the engine running and the AC turned on to the MAX-AC setting, check under the hood to see what the AC compressor is up to. It will be a large, belt-driven unit at the front of the engine with two aluminum lines bolted to it. Take a look at the front of the compressor where the belt pulley is attached. At the face of this pulley, you will find the AC compressor clutch (an electro-magnetic unit that engages the compressor on demand). If the clutch is spinning then stopping with a click, then spinning again, the system has most likely lost its refrigerant gas charge (usually two to four pounds) and a pressure cut-off switch is preventing the compressor from operating. If the compressor clutch never tries to engage and spin, there may be a control or electrical fault in the system. Few shops will inspect an AC system without charging some type of fee.

Most leaks can only be pinpointed by injecting a fluorescent dye into the system. This requires special equipment and, in many provinces, an extra accreditation to a technician’s licence. The average fee for a basic AC inspection runs around the $100 mark. For backyard techs, many auto parts stores sell a DIY recharge and sealant kit. Be warned that these kits contain a butane derivative as their refrigerant gas. As you might suspect, this substance is flammable. When you consider that the largest portion of AC gas circulates through the condenser at the very front of the vehicle, you might be excused for wondering why you would want to put a flammable gas at the most common collision point of your car. In addition many shops will refuse to attach their AC recharging station to a vehicle that has any leak-sealant in it. This sealant can cause expensive problems in their equipment, and no shop owner wants his or her AC equipment down for repairs in the busy season. AC repairs can get expensive with repairs bills topping the $1,000 mark on a regular basis.

If you’re driving an older vehicle (seven to eight years or older), you may want to think twice before dropping some large coin on an AC repair. If the compressor has failed, many car owners may think they have no alternative but to repair the fault because the compressor drive belt may operate other necessary components such as alternators, water-pumps, and-or power steering pumps. how much does it cost to replace an ac unit in a carIn cases such as these, you might want to have your shop check for an AC bypass pulley. how long do outside ac units lastFor popular makes and models, they may be available from aftermarket suppliers at a fraction of the cost of a compressor.how much ac units cost If your vehicle’s AC system is working, but just doesn’t seem to have the chill it used to, check the condenser, usually located just in front of the engine radiator.

If you can see more grit, gravel, and dirt than tubing and fins, it may just need a little cleaning. These condensers are rather fragile; so don’t go at them with any tools or high-pressure washers. You can easily flush out most dirt by using a normal garden hose low-pressure sprayer pointed towards the front of the vehicle from the engine side of the radiator or condenser. Another home driveway repair you can handle yourself is cleaning the condensation drain. Like any AC system, vehicle units create a substantial amount of condensation. With cars, this water is collected in a tray under the evaporator coil found under the dash. The tray has a drain tube that runs through the firewall into the engine bay letting the water drip onto the ground. Most of these drains are formed so that the end has a flap that stays closed when no water is draining to prevent road dirt and dust from getting into the passenger cabin (think of the working end of a whoopee cushion tube). If this flap sticks shut, your front seat passenger will end up with a very cold pair of feet when the drain tray overflows.

If you’ve been running your car’s AC on a hot humid day and don’t see any water dripping out, locate the drain tube on the engine side of the firewall and squeeze the end to pop it open.Why is the car defroster only blowing cold air? If the defroster is unable to blow hot air, there may be a clog in the cooling system or a malfunction of one of the actuators for the vent doors. The cooling system and actuators will need to be properly inspected to find the source of the issue. What is a secondary air injection system malfunction? What are the possible reasons for your car's CD player not working? Why does the car heater not blow cold air? A defroster produces heat using a heater core, which uses coolant to heat the air for a vehicle. Hoses run coolant into the heater core, which warms the air and sends it through the vents. There are several components in the climate control system that can malfunction and cause it to clog. When this occurs, the thermostat, heater core and radiator should be promptly inspected.

The actuators are special flaps that control the flow of air in the climate control system. When these doors are stuck shut, the heated air will not be able to reach the cabin of the vehicle. The following instructions explain how to troubleshoot the actuators.Locate the actuatorsThe placement of the actuators vary on the vehicle and are generally located behind the dashboard. The dashboard may need to be removed.Test the actuatorSome actuators use air vacuums to function, while other use a cable. Test the door to see whether or not it opens and closes.Replace the actuatorAn actuator cannot be rebuilt, and if a part is malfunctioning, then the unit must be replaced.Test the actuatorReinstall each part previously removed and test the new actuator. What is the most likely cause for a car's heater to blow cold air? The most common causes of an automobile heater blowing cold air relate to the heater core. This unit is a small radiator the manufacturer installs inside t... What are some reasons for car immobilizer repairs?