Are You Experiencing BMW Air Conditioning Issues?
In Bavaria, a working AC might be a luxury, and indeed some BMWs sold in their home market don’t come with an AC system, but here in Florida even your bargain-basement Ford has an AC as standard. We’re so used to it being there, that we don’t really think about it. Until it stops working, that is. If you’ve got a BMW with air conditioning issues, then this article is for you.
Interestingly enough the standard ac system that we take for granted today was never actually intended to be used for climate control. It was invented in New York to make the large scale printing process more efficient, then gradually progressed to making the workplace more efficient and finally the home and auto more comfortable.
Exactly how does it work though? Basically, it relies on an age-old physics principle that expanding (evaporating) a compressed gas (refrigerant) cools the immediate surroundings while condensing it heats them up. The refrigerant is compressed by a compressor driven by your BMW engine by a belt, heat is then removed from the gas by running it through a condenser (mounted in front of the radiator). The refrigerant is then expanded inside the BMW cabin by the evaporator, reducing the cabin temperature, then returned to the compressor via a drier to remove any moisture (prevents corrosion). The cycle forms a continuous closed loop. Its robustness is a testament to it withstanding almost a century of use without much modification (other than changes to the refrigerant to make it more environmentally friendly).
So, let’s take a look at the two main BMW air conditioning issues:
1. AC Odor
What’s the odor coming from my BMW’s air conditioning systems?
Moldy Smell
Many higher-spec BMW’s have a special electronic ozone cleaning system designed to eliminate AC odor but if yours smells musty, it is most likely a clogged cabin air (pollen) filter. If your BMW is regularly serviced by a trusted mechanic, these will usually get changed every second interval or two years. They are fairly critical to the cabin air quality as they remove a lot of particulate pollutants, which can be bad for your health. Today it is more important than ever to keep healthy, if you don’t know when last your filter was changed, we strongly suggest that you get it done soon.
Sweet Chemical Odors
Often indicate an engine coolant leaks, which isn’t an AC fault but should be checked urgently as it could cause your BMW to overheat.
Gas
If your AC smells like gas, there is something wrong with your BMW’s fueling system. A leaking fuel line could cause a fire and is very dangerous. We recommend that you stop at once and check for any visible gas leaks under the hood. If you can’t find the fault, get it checked by a reputable shop.
2. AC Blows Hot Instead Of Cold
What does it mean when your AC stops blowing cool air?
Refrigerant Level
If you drive an older model BMW, it is possible that your AC refrigerant is low. The refrigerant also lubricates the AC system, so it senses the pressure and won’t run if it is too low. Unfortunately, the AC light will still come on, but no cooling will happen. The easiest way to test this is to start the car with the hood open. Find the AC compressor and check that the belt driving it is good. Then get a friend to switch on the AC while you watch the compressor. If there is enough refrigerant, you should hear a ‘click’ from the compressor and the engine will blip ever so slightly as an additional load gets added to it. If this isn’t happening, chances are good you’re low on refrigerant.
Another sign of low refrigerant is the passenger side vents on your BMW blowing colder than the drivers. Refrigerant should be topped up by a professional shop since modern systems are very sensitive to over-pressurization.
Blocked Condenser or Faulty Fans
Air conditioning is all about airflow; since this helps to remove heat. For air to be able to pass through the condenser it needs to be free of obstructions. Any bugs and mud can be hosed off fairly easily. The condenser and the radiator are usually cooled by the same fan, but some BMW’s have two separate ones. The easiest way to test the fans is to start the engine and put the AC on full blast. This should automatically trigger the condenser fan. If it doesn’t start you’ve either got a faulty fan, or a faulty computer control unit.
Dying Battery
Modern AC units are all computer-controlled. Microcontrollers require a stable voltage and current supply. If your BMW battery is weak or there is a fault with the alternator, chances are quite good the AC will malfunction.
Hopefully, by now you’ve got a good idea of what might cause your BMW air conditioning issues. Unless you enjoy taking a BMW sauna (we won’t judge), why not pop into our Pompano Beach shop and chill out with Foreign Affairs Motorwerks?