Car Air Conditioner Quit Then Started Again

Car Air-conditioning blows cold then blows warm

Auto Air-conditioning blows cold then warm

If your car AC blows cold then warm, the cause tin can exist a low system charge, wet in the system, a malfunctioning expansion valve, clogged evaporator fins or an overcharge status. Here's how to nail down the cause.

Low car AC charge causes evaporator freeze up and low airflow

A low system accuse tin cause the evaporator ringlet to and then cold that it freezes the condensation on the evaporator fins. The ice builds upward until information technology blocks airflow. Then the AC system shuts off the compressor and you lot get warm humid air.

Evaporator gyre

You would think it would be only the contrary; that a low charge would cause it to never become cold enough to freeze. To understand why that's wrong, yous offset have to understand how refrigerant works.

As the liquid refrigerant is metered into the evaporator (the cooling coil inside the passenger compartment), the liquid refrigerant picks up heat from the cabin air flowing across the coil. That heat causes the refrigerant to eddy and alter from a liquid to a gas. All the refrigerant needs is simply enough estrus to crusade that "change in state" from liquid to gas. Removing that corporeality of oestrus from the motel of your car is what causes your automobile to feel cool.

The proper refrigerant charge volition cause the evaporator to remain slightly to a higher place the freezing temperature and produce an air temp around twoscore°F

One time the refrigerant has changed states to a gas, it should pick up a maximum of 10°F more heat and then menstruum out of the evaporator into either the compressor or accumulator to complete the cycle.

But when a organisation is low on charge, the gaseous refrigerant stays in the evaporator longer and removes even more than heat from the cabin air passing over the coil. The refrigerant leaving the evaporator is superheated by more than x°F. The additional heat the refrigerant removed from the motel air causes the evaporator temperature to fall below freezing. Humidity in the cabin air freezes on the evaporator. Over time, the moisture builds to the betoken where ice blocks the menstruum of air across the evaporator. That shuts off the AC and you no longer get cooling.

Chock-full cabin air filter can also cause evaporator freeze upward

But like the situation with low refrigerant charge, depression airflow caused by a clogged cabin air filter causes the refrigerant to remove too much heat, causing evaporator to freeze.

Cabin air filter catch all the droppings from fresh air, like leaves, grit, and pollen

If your motorcar has a cabin air filter and you think you might accept an evaporator freeze up problem, first past checking the status of your motel air filter.

Wet in the AC system can also crusade an Air-conditioning blows common cold then warm status

Any time you lose refrigerant from your car'south Air-conditioning system, that leak allows air and wet to enter. If you but add more refrigerant every year without fixing the leak, y'all build up also much internal moisture.

The moisture tin freeze into ice crystals right at the orifice tube or expansion valve, clogging it and stopping the period. The symptom appears every bit: blows cold, and so warm. If yous shut off turn on the heat for a while, that'll melt the ice crystals and the system will start cooling again. But it will all the same freeze up.

How to tell whether your Air-conditioning has depression charge or moisture?

When an evaporator freezes due to low charge, you'll also have decreased airflow because the ice is blocking the air. If you shut off the vehicle and get out it for a one-half hr or so, you lot'll see a huge pool of water under the vehicle. That's the sign of a depression charge. All the ice has melted and tuckered out the condensation tube onto the ground.

If the Air-conditioning blows cold and so warm condition was caused past moisture in the system, yous won't find a subtract in airflow and you won't come across a pool of water later on shutting off the vehicle.

Some other crusade of AC blows cold then warm

An overcharged car Air conditioning system can start out pumping common cold air. Merely that cold air turns warm fairly soon subsequently because the high side pressures build to the signal that the high force per unit area switch shuts off the compressor clutch. One time pressures equalize, the high pressure switch allows the compressor to kickoff upwardly again. The cycle repeats over and over, providing a brusque period of cold air, followed past warm air. The fix? Evacuate and recharge the car Air-conditioning system.

Yet another crusade of AC blows common cold then warm

If your car Ac blows cold air when driving at highway speeds but turns warm at stop lights or when driving at slow speeds, you may have a bad radiator fan or radiator fan relay. Many cars are equipped with two radiator fans, while others have i fan that can run at different speeds. In cars with dual fans, ane fan is designed to run at full speed whatever time the Air conditioning is on. If that fan isn't working properly, it tin't cool the condenser plenty to remove enough oestrus from the gaseous refrigerant to get information technology to condense back into a liquid. That also causes high pressures that can close off the compressor. The fix? Check the radiator fans to brand certain at least one fan turns one when the AC is switched on.

However, some cars operate both fans at depression speed while driving and switch into high speed mode when the Air conditioning is running. Then become tricked into thinking your fans are ok only considering they're running. They must run at high speed in guild to depict enough air across the condenser to make the organization cool properly.

Well-nigh common reasons car AC won't cool

©, 2017 Rick Muscoplat

Posted on July xiii, 2017 by Rick Muscoplat

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