BMW A/C Guide

From the entry-level BMW 3-series to the top of the line 8-series, every BMW car comes equipped with climate control. It is not just a feature; it is the company’s standard. Even though you might not get the heated seats or automatic climate controls, your BMW will still have A/C as standard. 

Interior comfort is one of the many reasons why we need a good air conditioning system in our car. And when it comes to interior comfort, BMW has always been one of the best in the market. 

But then again, no matter how good anything was in beginning, it will always come to an end. Air conditioning is no different. They sure make our life a lot easier and comfortable, but with time their cooling also starts to fade. And then you ask, 

Why is my BMW A/C not cold enough?

Well, when you talk about A/C not working properly, it means that your A/C is malfunctioning. Now malfunctioning can be caused due to several reasons. But when we talk about A/C not being cold enough, well then, the reasons are obvious. It is more than likely your compressor. 

If your vents are throwing less volume of air or you see dust or the air smells different, that will be a bad cabin micro-filter. But otherwise, it’s either your bad compressor or it's just out of juice.  To understand it better lets first understand the working of an Air conditioning system. 

How does my BMW A/C work?

The functioning of an air conditioning system is really simple and it is about the same in almost all cars. The first thing you need to understand is that your A/C does not create or generate cold air, it simply converts hot air into the cold. Your A/C system does so by either regulating the cabin air or bringing it in from the outside. 

It all starts from one unit called a compressor. It is a device that is used to reduce the volume of gas by increasing its pressure. Due to an increase in pressure the temperature also increases. Now, this hot gas moves into another unit called the condenser. The condenser is like a radiator and as the gas moves through it, it loses its temperature while being at the same pressure.

This in turn converts the gas into a liquid. Now the liquid moves through a dryer which separates liquid from any remaining gas. Then the liquid moves to a thermal expansion valve which then simply turns your hot high-pressure liquid into a cold, low-pressure gas(magic). The cold gas is now passed through an evaporator which is also like a radiator

The hot air from the outside or from your cabin then passes through the evaporator. As the hot air comes into contact with the cold gas, the air loses its heat and you get cold air from your vents. 

Then the cold gas from the evaporator goes back into the compressor and a cycle is created. This is how your air conditioning works. 

You might be wondering, how does this explain your A/C not cooling air. There are two answers to that. 

  1. Any one of the many AC components have stop working. 
  2. Your compressor has run out of refrigerant. 

What is refrigerant? 

A refrigerant or freon is a substance used to transfer heat from one area to another. Yes, it is the same substance that keeps converting into liquid and gas as explained above. With time your car runs out of refrigerant and you need to recharge it. 

Without refrigerant, your compressor will not work, and your evaporator will not have any cold gas to convert hot air into cold. 

But how would you know whether you have a malfunctioning AC or your BMW just don’t have enough refrigerant?

How to diagnose BMW A/C system?

To be honest, diagnosing your BMW’s A/C system comes down to a little knowledge and common sense. How?

Since we already know about all the basic parts of an AC unit, all we have to do is figure out is what is missing. So, we check facts like “Is the A/C fan working?”

If you turn on your A/C and your fans are not working, then that is most likely a switch issue or maybe you have broken fans. But if your fans are working fine and still you are not getting adequate air then that is a clogged cabin micro-filter. 

However, if your fans are working and you get adequate air then the only chance that you have a compressor problem is when the air is not cold at all. In a scenario, where even the A/C is giving out cold air, but not as cold as it used to be, only then, you have a refrigerant issue. 

So, let’s fix it. 

How to recharge the BMW A/C?  

To recharge your BMW refrigerant, you will first need an A/C recharge kit which you can get that at any Auto part shop. As for the amount of refrigerant needed, you can either check the owner’s manual, contact dealership, or check this chart

 

Once you have your BMW AC Recharge kit, it is time to get charging. 

  1. First, turn on your engine, then turn on your AC. Set your blower to max and reduce your temperature to minimum. Don’t forget to take a reading, just to be sure. 
  2. Now open the hood and locate your Air conditioner’s low-pressure charging port. It will next to your engine cover with black or blue plastic cap. Do check your owner’s manual or use the image below as a reference to locate it accurately.
  3. Remove the cap(anti-clockwise) and connect you’re A/C recharge kit to the low-pressure line. This will give you a reading on your refrigerant pressure. 
  4. Now check your reading and check the tag on your A/C recharge kit to confirm that your refrigerant is low. 
  5. Simply remove the cap of your recharge kit, and gently press on the trigger. Make sure that your container is upright. 
  6. It is a slow process, so you have to be patient. After a few seconds, you will see the pressure rising. Keep the refill going until it reaches the optimum pressure or the blue area.
  7. After you are done refilling, just go inside your car and check you A/C temperature. It should be colder then before.
  8. Once that is confirmed, disconnect your recharge kit, tighten the A/C port cap(clock-wise) and close the hood. And that is how you recharge your A/C. 

How much does BMW A/C recharge cost?

The total cost of getting your refrigerant refill or A/C recharge will not be more than $250, even if you go to a dealership. 

However, it is something so common and easy, that you can do it at home in under 10 minutes and $80 with an average recharge kit. But if doing so doesn’t solve your cooling problem, then it’s better to contact your dealership. 

How often should you recharge your A/C?

Recharging your A/C doesn’t come with a time period or expiry date. There is no time limit or frequency to how often you should recharge your air conditioning. It depends on the area you live in and the amount of time you use A/C and at what intensity you use your air conditioning. 

So, if I were to answer how often should you refill your refrigerant, it would be till the time it’s not cold enough.  Until then, enjoy!

 
Categories: Service, Parts