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ZeroR R134a AC Refrigerant Top Off Kit

How to recharge your car r134a AC system

Can I recharge my car AC myself? Absolutely! Is your car’s AC system gradually blowing warmer and warmer air and not cooling your car’s interior? Over time, it is normal for car AC system to leak or lose refrigerant when the seals get old and, in most cases, simply topping off the R134a refrigerant level in your car’s AC system will fix the problem. In this article below we will show you everything you need to know about how to recharge your R134a car ac system refrigerant in simple, easy-to-follow steps.

Some Things You Should Know First

Generally, if your vehicle was made after 1993 your car AC system will probably use R-134a refrigerant. To be sure, check your owner’s manual refrigerant specifications section (you can check online too) or look for the label under the hood (locations pointed out in the video) to make sure your car’s AC system uses R-134a refrigerant. A majority of car AC cooling systems on the road today use R134a refrigerant but newer cars are using R1234yf for environmental reasons as the January 1st, 2024 ban date on R134a refrigerants approaches.

Topping off your refrigerant will not fix all AC problems. But if you have the time and money to buy an ac recharging kit, in less than half an hour you might solve the problem. You will probably save about $100 in labor costs by doing the job yourself.

Be Careful with Car AC Refrigerants!

Car A/C Refrigerants are cold! Because refrigerants can cause frostbite and permanent eye damage it is always a good idea to wear protective gloves and safety glasses.

Disclaimer: This how-to information is not for hybrid vehicle air conditioning systems. Air conditioning recharge compressors used in hybrid vehicles are incompatible with the oils and seal conditioners used in many retail recharging kits. Using the wrong auto air conditioning  recharge kit can result in a lethal electrical shock. We recommend using an A/C recharge kit and how-to information specifically intended for your hybrid vehicle!

Things You Will Need To Top Off Your R 134a Air Conditioner

Step 1: Turn On Your Car and A/C

To recharge or top off the refrigerant in your car’s air conditioning system you will first need to turn your car on, turn your air conditioner on to the highest fan setting, set to the coldest setting and open the vehicle doors to prevent the air conditioner from shutting off when it gets cool in the cabin, letting the engine and AC system run for 5 minutes or so before adding refrigerant.

Step 2: Locate Your Low-Pressure Port and Attach Your Gauge

In most cases, the Low Pressure Service Port access cap is marked with a letter “L” to help identify it. Pro Tip: When you take off the Low Pressure Port cap just stick it in your pocket to prevent loss or having to search for it all over or under your engine compartment. Generally, a quick YouTube or Google search for “where is the low side port for a [your car’s year] [your car’s make] [your car’s model]” will provide a visual example for you from your cars type’s engine bay.

All automotive AC Systems have two service ports: A high side service port and a low side service port. Always use the low side service port. It will have a larger diameter metal pipe than the high-side and is usually located between the AC compressor and the evaporator. Don’t worry! The low side service port is the only access port to which the ZeroR® R 134a AC Refrigerant Top Off Kit pressure gauge coupler will connect in your car’s air conditioner.

Step 3: Check the Compressor Clutch to See If It’s Engaging

The easiest way to see if your compressor clutch is engaging is to look for the belt pulley to be spinning. See our video below for helpful information in finding your compressor/clutch pulley.

If the clutch pulley is not spinning, then the AC system is either very low on refrigerant, has an electrical problem, or the compressor itself has failed. Adding more refrigerant after pressure testing may indicate which is the cause. However, if the AC compressor does not engage you won’t be able to install refrigerant. But the chances of a compressor failure being the issue is very low compared to just the low refrigerant issue.

Step 4: Test Your A/C System Pressure

Now that the engine has been running and the AC turned on to it’s maximum cold and fan settings for 5 minutes or longer, you are going to check the level of your AC system’s pressure. Check the instructions that came with your gauge (some are different than others!) and familiarize yourself with the color of the background on the gauge that represents the desired AC pressure gauge range.

After removing the AC Low Side Port cap, the ZeroR® R 134a AC Refrigerant Top Off Kit hose quick-connector has a small flange or ring around it that you will pull up with your fingers and then slide the connector down snugly over the port, releasing the quick-connector ring, and checking for a snug fit. You should not be able to slide the quick-connector back off now without first pulling up on the flange/ring.

Ideally, the PSI (Pounds Per Square Inch) pressure reading on the refrigerant gauge should be at 40 PSI, shown in the middle of the blue area of the gauge dial. Note: Some refrigerant pressure gauges use different colors to indicate the optimal amount of pressure range but they all work the same way. If your refrigerant pressure reading is under 40 PSI, your system is under-charged and needs to have car AC refrigerant added. Normally, 40 PSI will be found in the middle of your gauge’s desirable pressure range, no matter what the color. Pressure readings are always immediate and you don’t have to wait for them.

System refrigerant pressure significantly over 40psi or, over the blue area of the gauge is considered “high” low side pressure. Possible causes are overcharging the refrigerant system or the compressor itself is malfunctioning. If you overfill your system with refrigerant, you simply turn your car off and then engage the can tap to allow refrigerant to fill back into the can. This prevents both refrigerant waste and the leakage of refrigerant into the environment.

If it is in the red area of the dial (this may very by gauge manufacturer), you may have a more serious issue with your car AC and will need a certified mechanic to diagnose and fix the problem.

Step 5: Disconnect The ZeroR® R134a AC Refrigerant Top Off Kit

That’s it!

Don’t forget to put the cap back on the AC Low Side Port and most importantly, enjoy the cool air and savings of time and money!