Why does my AC go from cold to warm?

Asked By: Danna Sperlein | Last Updated: 2nd March, 2020
Category: home and garden indoor environmental quality
4.4/5 (736 Views . 34 Votes)
Car AC blows cold then warm. If your car AC blows cold then warm, the cause can be a low system charge, moisture in the system, a malfunctioning expansion valve, clogged evaporator fins or an overcharge condition.

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Keeping this in consideration, why does my car AC not get cold?

The most common causes of broken air conditioning are leaks or compressor issues. If your air is blowing cool but not cold, the problem could be a clogged filter, cooling fan problem, radiator trouble, or it could simply be that you need to recharge your AC.

Similarly, why is AC not cooling enough? Improve air flow. In addition to the air filter, your AC may have other types of air flow problems. If the evaporator coil is dirty, not enough air moves across it and your home doesn't cool off as well as it should. If the condenser coil is dirty, it won't dump enough heat to the outside.

Simply so, why is my AC blowing warm air in my car?

Hot air coming from your car AC vents can mean that you have low levels of refrigerant. It can also be due to a problem in the condenser, the compressor, the cooling fan, or the electrical system of your car.

Is it better to leave AC on auto or on?

The fan only runs when the furnace tells it to. On cooling, the fan will run only when the air conditioner is running. Pros. The "auto" setting means less energy usage, because it keeps the fan running the least amount of time at the slowest speed needed for heating and cooling.

25 Related Question Answers Found

What is the coldest temperature for an air conditioner?

If there is moisture in the air which would collect on the evaporator and restrict air flow, the coolest useful air temperature would be restricted to just above 32 degrees Fahrenheit or before the moisture in the air would turn to ice.

Why does AC only work when car is moving?

When the car is moving, versus stopped, there is more air flow over the condenser (the heat exchanger in front of the radiator) and that airflow is essential to system operation. Other possibilities are that the compressor clutch is not cycling as intended or that the condenser might be blocked or dirty.

How cold should my AC be at the vent in my car?

Proper auto A/C vents temperature. In general, with ambient air temperatures 70 degrees Fahrenheit and humidity 20 %, the evaporator outlet air temperature should be in the 35 -40 degrees Fahrenheit range.

Should auto AC lines be insulated?

Yes ,You should insulate the piping of any air condition not only on your car but its a general rule that the piping from the compressor be insulated. This will not only prevent heat loss but this will also improve the life of the pipe itself.

Does coolant affect air conditioning?

In a properly operation system the engine coolant temperature should not affect the cooling of the air conditioner. But technically it is not the high coolant temperature causing the A/C problem. It is the lack of airflow across the condenser and radiator causing one problem in two systems.

Can AutoZone recharge AC?

When it's time for an AC recharge, turn to AutoZone. We carry R134a refrigerant, PAG46 oil, AC stop leak, AC system cleaner, and more. You can shop online for same day in-store pick up or go to your local AutoZone to find the right AC solution for you and your vehicle.

What are the symptoms of a bad AC compressor?

Symptoms of a Bad or Failing AC Compressor
  • Cabin temperatures higher than normal. One of the first signs that a compressor may be having trouble is the AC no longer blowing as cold as it once did.
  • Loud noises when the compressor is running.
  • Compressor clutch is not moving.

Why is my AC blowing hot air after recharge?

Leaking Coolant
The chemical Freon or simply you can call it coolant is the reason why the AC cools hot air quickly. The chemical can run out if there is any leakage in the AC. Thus, AC would not work, as there is no Freon in the system.

How do I know if my car AC needs freon?

Well, there are a few signs to look for.
  1. Room Temperature Air. One of the most characteristic symptoms of low freon is the presence of room temperature air blowing from the vents.
  2. Visible Leaks. Of course, another sign of low freon levels is a visible leak.
  3. Clutch Doesn't Engage.
  4. Ice on Compressor.

How much does it cost to recharge AC?

For most cars, the cost of an AC recharge will be about $200 but can go as high as $280. It's a simple procedure, but it can take a while to check everything out and ensure that there is no further damage, so expect to pay about $120 for the labor costs.

Why is my AC blowing warm air?

Most likely, if you're having issues with your air conditioner blowing hot or warm air, it's either a problem with the compressor/outside unit or your air conditioner is low on refrigerant. You may also have a return duct that is broken or disconnected and is pulling in unconditioned air from outside or an attic space.

Will a bad AC compressor affect the engine?

Without the AC on the clutch will not engage and the AC compressor will not turn an therefore have no effect on the engine. The compressor works, but it doesn't shut off, and I've added the proper amount of r-134 refrigerant.

Why is my AC running but not cooling?

There are a couple of reasons for ice buildup in your AC — dirty coils or filters resulting in poor airflow, or a lack of refrigerant. If that doesn't get the unit blowing cold air again, it could be refrigerant levels are low (see below).

How much does it cost to fix your air conditioning in your car?

This generally includes replacing a few parts like hoses, sensors, or either the compressor or condenser. CostHelper readers report paying $171-$727 for minor air conditioning repairs, at an average cost of $488. Extensive auto air conditioning repairs can cost $1,000-$4,000 or more, depending on make and model.

How do I reset my air conditioner?

Here are the steps you need to take to reset your AC thermostat.
  1. Shut Down Your AC at the Thermostat. The first step in resetting your AC thermostat is to turn it off at the AC unit.
  2. Find Your Circuit Breaker Box.
  3. Reset the Circuit Breaker for Your AC Unit.
  4. Wait 30 Seconds.
  5. Turn the AC Thermostat Back On.

Why is my car blowing hot air on one side and cold on the other?

This situation can be caused by a bad blend door (also called air mix) actuator, a broken or binding blend/air mix door, broken linkage to the blend/air mix door, or a faulty HVAC control head or wiring harness.