Question: I’m a bit overdue on a coolant flush and I’ve noticed that my AC isn’t working as well as it used to. Does coolant affect air conditioning?
Answer:
Yes—air conditioning (AC) temperature, air flow and even humidity can be impacted if you have low coolant levels.
Your car’s air conditioning system uses refrigerant, while your car’s engine uses a mixture of water and antifreeze called coolant to maintain a healthy temperature. But engine coolant is not just an integral part to your engine’s performance, because it’s also needed for your car’s AC system to operate at peak performance.
The main purpose of your car’s AC system is to cool down the interior of the vehicle, making for a more comfortable ride. If its coolant level is low, your car will struggle to maintain optimal engine temperature—and in turn, your AC system will not receive the cooling capacity that it needs to run smoothly. Energy and efficiency will go toward cooling your engine, leading to reduced effectiveness and a weekend airflow throughout the AC system.
The AC system can also change the humidity levels in your vehicle. For example, your car’s AC system is intertwined with your defrost system. When you turn your defrost on, the AC starts to blow warm air to dehumidify the window. If low coolant levels have the system not running at peak efficiency, then the defrost system will also struggle, leading to higher humidity levels in the car. That struggling AC system may also generally struggle to take any moisture out of the cabin when trying to run normally.
While coolant levels can have an impact on the AC system, keep in mind that coolant is for the engine itself. If your AC is not running properly, it’s most commonly an issue with the AC system itself. Leaks in the system or compressor issues are the most common culprits. However, it could also be a problem with the cooling fan, filter, or a simple case of the system just needing to be fully recharged. While you can recharge the system yourself with a little knowhow, it’s best to seek out your local mechanic should you suspect an issue with your AC system is causing it to run improperly.
How do I add the coolant to my engine?
If you find yourself low on coolant, you can easily top off the system yourself—but how to do so can differ depending on your vehicle. You can usually add coolant one of two ways: via the reservoir or directly through the radiator.
Adding coolant via the reservoir
Follow these steps:
- Make sure your car is off and has adequately cooled down.
- Locate the coolant reservoir, which is usually a clear, plastic tank near your radiator.
- Put on gloves and safety glasses before slowly removing the reservoir cap to release pressure.
- Prepare your coolant by making sure it’s the right type and mixture for your vehicle, which you should be able to find in the manual.
- Fill the reservoir to the max fill line by using a funnel.
- Slowly replace the cap until it is tight and close the hood.
Adding coolant via the radiator
Adding coolant via the radiator is very similar to the reservoir option. To do so, follow these steps:
- Make sure your car is off, and has been so for long enough to adequately cool down.
- Locate the radiator.
- Slowly remove its cap to release pressure.
- Prepare your coolant mixture, making sure it’s the right type for your vehicle, and pour it into the radiator via a funnel until the coolant level is once again full.
- Slowly replace the cap until it is tight and close the hood.
Before filling up your coolant, it’s important to check the owners manual to make sure your vehicle doesn’t require any added or specific steps.
Chris Burkhardt is a writer and editor with over a decade of experience across various storytelling mediums. With Jerry, Chris hopes to help anyone with a question about their vehicle easily find the answers they are looking for. Whether you need to know how much insurance costs for a classic car, how to replace a broken light or tell if you need an oil change, Chris wants to help you find solutions the best he can. Prior to joining Jerry, Chris was a digital content producer and writer for NBC and a freelance editor for NerdWallet. A graduate of the University of Oregon’s School of Journalism and Communication, if Chris is not working on content, he’s sure to be found cheering on his Ducks!
Everett Cook is an award-winning journalist and editor with more than 10 years of experience across a variety of industries. In editing for Jerry, Everett’s mission is to help readers have a better understanding of the costs of owning or leasing a car and to better understand their vehicle in terms of insurance and repairs. Prior to joining Jerry, Everett was an editor for Axios. His previous work has been featured in The New York Times, The Los Angeles Times, The San Francisco Chronicle, The Atlantic, Atlantic Re:think, The Boston Globe, USA Today, and others. He’s also been a freelance writer and editor with experience in SEO, audience building, and long-term content roadmaps. Everett is a proud graduate of the University of Michigan.
