How To Flush Your Car AC System (DIY Cleaning Guide)

To keep the HVAC system in your car working right, you need to perform regular maintenance. Learning how to clean the car air conditioner is a vital way to ensure the cabin is comfortable, especially when it gets hot.

In this article, we cover how to clean a car AC system and show you the way to perform a DIY car AC flush, as well as how to clean the vents properly.

How To Flush Your Car AC: DIY Cleaning Guide

What You’ll Need

To learn how to flush car AC lines, you will need some sophisticated equipment. For this reason, many people choose not to learn how to flush your car AC system and take it to a local shop instead. If you choose to clean out the car AC system yourself, these are the parts you need.

  • Manifold gauges
  • AC recovery machine
  • Air compressor
  • Refrigerant
  • Fine brush
  • Car vacuum
  • Cleaner of your choice
  • Steam cleaner
  • New cabin air filter
How To Flush Car AC System

Steps To Flush Car AC

  1. Use a fine brush made with microfiber to dust each air vent individually. You don’t need to remove car AC vents just yet.
  2. While brushing, dust is going to break loose. Hold a car vacuum close to your work to suck out the dust as it is removed.
  3. You will want to spray a clean air car vent cleaner onto the dusted area to completely clean it. You can also use a steam cleaner for deeper disinfection. Just make sure the vents are dry when you are finished, or you encourage the growth of mold.
  4. Change the cabin air filter because it can become blocked and dirty causing further musty smells. If filter is new, cleaning the car or RV AC filter also helps.
  5. From outside of the car, you want to spray compressed air into the intake vents. Do this while you have the ventilation running in the vehicle, so all of the air can escape.
  6. Connect the manifold gauges to the fittings. With the recovery machine, you want to completely evacuate the system. You can’t move on until the pressure is reading 0 psi.
  7. Remove the refrigerant hose from both sides of the condenser (low and high).
  8. Start cleaning the car AC condenser by shooting compressed air into the high side, thereby forcing debris from the outlet hole in the condenser. Keep doing this until all contaminants get removed from the air conditioning. If the condenser contains an internal tubing, there’s no way to flush it. Instead, you would need to replace it.
  9. You are now ready to learn how to clean an AC accumulator. Remove the mounting brackets securing the accumulator, plus the expansion valve or orifice tube. Inspect these parts for any signs of damage. Replace them if needed.
  10. If you want to learn how to clean the car AC compressor, you can drain it and refill it with refrigerant oil. You can also clean out the car AC evaporator, but this could be difficult to reach.
  11. Once the system is free from debris, you can reassemble everything. It’s also time to put refrigerant back into the system. Recharge it to the appropriate specifications and ensure the proper pressure is set.
  12. With the air conditioner running for about ten minutes, you can also check for leaks with a dye that’s injected into the system.
  13. With special sprays, you can disinfect the car AC. You can also use a vacuum cleaner to remove any debris or dust stuck in the vents.

If any of these tasks seem too complicated for you, it’s best to visit a qualified shop to have the flush performed. If you damage one part in the process, you could be looking at an extensive repair bill, making the at-home maintenance task not worth much.

How Does a Car’s Ventilation System Work?

The automotive ventilation system consists of the air conditioning and heating units all in one. Air gets pulled into the large duct located at the front of the vehicle while the car is moving. When the air enters, it gets heated or cooled, depending on the fan setting you have chosen.

Heating vs. cooling isn’t much different. When the heat setting is chosen, the air moves through the water-heated radiator while the fans push the air into the car. However, for cooling to occur, the refrigerant must be present in the AC system. This refrigerant gas gets compressed and converted to a liquid that moves through the condenser to remove heat. This process creates the cold air that gets pumped into the cabin.

What Exactly Is a Car Air Conditioner ‘Flush’?

Before you learn how to flush the car AC system, you want to know what this preventative service is.

Technicians flush the car AC system to clean out any sediment and sludge from the drains and hoses. During the car AC flush, technicians also check the system for leaks.

What Is Car AC Flush

Why Is Flushing The AC Necessary for Car Owners?

The typical car air conditioning cleaning ensures that the system is free of any contamination that would otherwise block efficiency. Anything that can block the valves, hoses, and lines can harm the air conditioning operation.

Blockages in the system can also keep the compressor from working correctly. If the flow of refrigerant or oil is blocked, the system fails to work as it should. The compressor requires oil for lubrication, just like the car motor. Without it, vital parts are going to wear out from the friction.

You can tell when it’s time to learn how to clean the aircon in a car. The air being pumped out will start appearing warmer, and the flow itself might be reduced.

Why Do You Need To Clean Your Car Vents?

Is there a benefit to having clean car AC vents? After all, it doesn’t make sense to learn how to clean out the car air vents if there is no benefit. In reality, there are a lot of reasons to consider cleaning AC vents in a car. For starters, you remove allergens and dust from the system. It can also help reduce the growth of bacteria and mildew.

You also want to know how to clean smelly air vents in a car if odors are present. In general, a car AC vent cleaning can dramatically improve the health and well-being of those inside the cabin while also prolonging the life of the air conditioning parts.

Related ArticleHow to Clean RC AC Filter

How To Tell That Your Car Vents Needs To Be Cleaned

Unpleasant Or Musty Smells Inside The Car

It’s important to clean out the air vents if you begin to smell anything undesirable or musty, similar to dirty gym socks in the car. These smells could indicate the beginning of mold or bacteria growth, which is why you want to take action immediately.

Visible Debris In The Car Vents

You probably aren’t easy on your vehicle, putting it through a lot of stress on a regular basis. Because of all that you use your vehicle for, debris can build up in the car vents, leading you to search out the best way to clean air vents in a car.

Dust, Pollution Or Pollen In Your Area

Even if you aren’t hard on the interior of your vehicle, it’s only natural for pollen, pollution, and other dust to start building up on the vents. Occasionally, you want to clean out the air vents in a car just to remove this build-up and prevent respiratory ailments.

How To Tell If Car Vents Needs Cleaning

People Also Ask (FAQ)

Is cleaning and flushing an AC the same thing?

The terms cleaning the AC or flushing the air conditioning can be used interchangeably. Both services ensure that the air conditioning system is free of debris that could lead to a blockage.

How often should you flush your car’s AC?

You want to schedule AC service on the vehicle once a year, particularly before it gets hot. As the technician checks the system, they will know whether it needs to be flushed or not.

How much does it cost to flush the car’s AC via a mechanic?

The typical car AC flush and recharge cost will be around $200. However, depending on the vehicle size and what needs to happen, you could spend slightly less or more.

How long does it take to flush the car’s AC?

It could take an hour or longer to flush the system. The most time-consuming aspect can be evacuating the system. If you don’t have the right equipment, it could take you longer to perform the task versus having a professional handle it.

What happens if you don’t clean your car vents?

Dust and debris will continue building up on the vents. This contamination could lead to the growth of bacteria or mold. Plus, it can reduce the amount of air coming out of the system.

How often should car AC vents be cleaned?

In normal conditions, you want to clean the vents every month or every other. However, if you are spending a lot of time in the vehicle or driving in dusty conditions, you may want to clean them more frequently.

Can you steam clean car vents?

You can use your steam cleaner on the car vents. The biggest trick to remember is that the vents must be completely dried when you are finished. Otherwise, your cleaning only encourages the growth of mold.

How do you remove car vents?

You shouldn’t need to remove the car vents to clean them. However, if removal is required, it’s important to read the directions in the service manual, ensuring that nothing gets broken in the process.


If you have the skills and equipment, you can perform your own AC flush on a car. It’s possible to save a little bit of money by performing this air conditioning service on your own.

Josh Mitchell

Josh Mitchell

My name is Josh and I am obsessed with DIY and improving my family home. HVAC topics can be tricky for homeowners so I decided to share my knowledge on the subject. When I am not working on DIY projects, you can find me at the beach or my local coffee shop.