Heated Air Blowing From Car Vents: Learn the Cause of It and How To Fix It

Are you tired of your car blowing hot air instead of cold? If so, you know how frustrating it can be to find the source of the problem. In this blog post, we will cover the most common causes of a car blowing hot air and offer tips for diagnosing and fixing the problem yourself, saving time and money by avoiding a trip to an expensive mechanic.


Common Causes of a Car Blowing Hot Air

Here are the most common reasons why your car blows hot air out of the vents:

Electricity Issues

A failure in safety devices, such as the instrument panel fuse, can cause an overload on other circuits throughout the vehicle’s electrical system, leading to the blower motor short-circuiting. This short-circuiting can cause an increase in voltage that could result in hot air blowing from the vents.

Clogged Air Filter

A clogged air filter prevents cool air from entering the engine, causing it to overheat and warm up the air in the vents. This can cause strain on other components of the engine, such as the radiator and hoses, leading to more serious issues.

Insufficient Refrigerant

The cooling system in the vehicle contains a mixture of refrigerant and oil, which helps absorb heat from the cabin air, keeping you comfortable while driving. When there is not enough coolant circulating throughout the engine, it won’t produce cold air. It will begin to blow warm, humid air into your vehicle instead.

Faulty Compressor

The compressor is the air conditioning system component that pumps cooled refrigerant gas through the rest of the system. If it stops working, heat from outside and within the car will blow out. This is usually caused by a leak or by failing bearings and seals.

Possible Solutions for a Car-Blowing Hot Air

If your car’s vents are venting hot air, here are some potential solutions to help you fix the issue:

Verify the Pressures: There are two types of pressure that need to be examined: static pressure, which includes low-pressure readings for freon levels, and system pressure, which determines whether it’s a problem with airflow or insufficient refrigerant. After determining the pressures, identify and replace any faulty parts that could help resolve the issue.

Locate and Remediate the Leak: Compressed gas or sealed containers can quickly refill the refrigerant and restore optimal air conditioning performance if a minor leak is discovered. If a larger leak exists, more extensive repair work may be required, such as replacing O-rings or hoses to ensure no further refrigerant escapes from the AC system.

Unplug the Compressor: If the compressor is not releasing cold air, unplugging it can stop hot air from being pushed into the vents, allowing outside air and cooler engine bay temperatures to be circulated through the vehicle. However, further investigation is necessary if this does not resolve the issue.

Take Your Vehicle to a Mechanic: It is also best to take your vehicle to a mechanic immediately to determine the issue and the best solution to resolve it. Depending on the findings, they suggest replacing a component such as a blower motor, evaporator core, or heater control valve. They can fix minor issues with car vents relatively quickly, such as an unclean filter, or determine more severe problems requiring replacements or component repairs.

How Much Will a Mechanic Charge to Repair the Issue?

Determining the cost of repairing an issue with hot air coming out of a car’s vents can range from $10 to $1,000, depending on the severity and complexity of the problem. If you need more confidence in your abilities, bringing your vehicle to a professional mechanic is best. They can quickly identify and repair the issue with your car and may even provide a warranty to fix any future car issues at no extra cost.

What Are the Risks Associated With DIY Repairs on Your Car’s Air Conditioning System?

Although DIY repairs on a car’s AC system are possible, it’s essential to consider the risks involved, including:

  • Causing further damage: If you don’t have professional-grade tools or experience working on car parts, you could cause additional damage to the vehicle.
  • Emitting chemicals: Without the proper procedures and safety practices, water and chemicals can enter the AC system and cause parts to malfunction or break down.
  • Incurring costly repairs: DIY repairs on your AC system could result in expensive repair services or even the replacement of system parts, which may exceed the amount you would have paid for professional repair.

Tips for Fixing the Car’s Vents from Blowing Hot Air

To address the issue of hot air coming out of the car’s vents, consider the following tips:

  • Diagnose the problem immediately and always take safety precautions when working on your car’s air conditioning system.
  • Clean your car’s air vents at least twice yearly and check for obstructions preventing airflow.
  • Before attempting any DIY repairs, ensure you understand what is required.
  • Take extra caution when working with chemicals or refrigerants. Always wear safety gear like gloves, goggles, and face masks.
  • Ensure a warranty covers any repair work serviced by a mechanic.
  • If you’re skeptical about fixing your car, bring it to a reliable servicing facility for a checkup.

Final Thoughts

Various factors, such as clogged filters and faulty components, can cause a car’s vent to blow hot air instead of cold. However, this issue is repairable. By addressing the underlying source of the problem, you can prevent further damage or the need to replace components in the long run. Apply the tips above to keep yourself informed and ensure your car’s air conditioning system works correctly.

About the author, Laurence Perkins

Laurence Perkins is the passionate car enthusiast behind the blog My Auto Machine. With over a decade of experience in the automotive industry, Perkins has knowledge and experience with a wide range of car makes and models. His particular interests lie in performance and modification, and his blog covers these topics in-depth. In addition to his own blog, Perkins is a respected voice in the automotive community and writes for various automotive publications. His insights and opinions on cars are highly sought-after.