How to Fix the AC on Your BMW

Car Tips, How-To | June 1st, 2017 by 15
BMW ac system repair 2 830x553

BMW cars aren’t known for having air conditioning problems, but if the air isn’t blowing cold when the temperature rises, that doesn’t matter for much. Just about every automotive air conditioning system subscribes to the same basic layout, which makes it simple to diagnose a problem because systems tend to break in the same ways. But how do you fix the AC in your BMW?

Once you know what the issue is, you can make an informed decision about whether you want to make repairs yourself or bring your car to the shop for help. Let’s take a look at how your AC system is built and some common issues.

BMW ac system repair 2 830x623

Basic Air Conditioning Parts

Your air conditioning system pulls air in from the atmosphere or recirculates the air in your car’s cabin. When it does, it runs the air over vanes full of super cold air conditioning fluid, which is called R134a in just about any modern system. After it cools the air, the fluid is warm, and it expands into an evaporator. Your system’s compressor is what brings the temperature of the refrigerant back down and allows the system to continue blowing cold.

There are also some external parts of your system, which include the HVAC controls on your dash, the vents you use to direct airflow and the fans that circulate cabin air.

Checking for Leaks

It’s easy to forget that the fluid in your AC system is in fact a working part of the system. If you have a leak, the system won’t work as well as it should. Some systems use fluid that is visible in black light, so if you suspect a leak, you can look for stains in your garage or parking spot.

Recharging the air conditioning system on your BMW is a straightforward process you can do yourself. Your local auto part store can probably sell you the fluid refill you’ll need, and you can complete the process itself in 15 minutes or so.

Air Conditioner Failure

Unfortunately, AC systems can break from the inside. This typically happens because of a phenomenon mechanics call the black death. Refrigerant breaks down inside your car’s compressor and causes the compressor internals to degrade and eventually jam. To avoid this, make sure you take your car in for an air conditioning system evaluation occasionally.

Other AC Issues

Perhaps there’s something hard to diagnose taking place with your bimmer’s AC. If the system doesn’t move air well, check the electric fans in your cabin and your HVAC dash controls to make sure they are functional.

Air that’s cool but not cold could be the result of a failed compressor or compressor clutch, or there could be an issue in your AC plumbing. A professional might be necessary to find the problem and fix it. If the air in your car smells funny, make sure you’ve changed the cabin air filter and you have cleaned any mold from the car’s evaporator case.

Owning the ultimate driving machine is a great experience, but when the sun is hot, a car without air conditioning is the ultimate torture device. Know how to look for the signs, and you can keep the AC in your BMW blowing strong and your passengers smiling.


15 responses to “How to Fix the AC on Your BMW”

  1. Lucky13 says:

    I’ve owned 16 BMW’s and never had an air conditioning problem. I read BMW blogs daily and can’t even remember ever seeing one about air conditioning problems. “BMW is known for having air conditioning issues?”, really. Must be a slow news day if you have to make up stories.

    • Scottmhuntington says:

      Try reading. “BMW cars aren’t known for having air conditioning problems” not “BMW is known”. So it’s saying “this doesn’t happen often, but when it does…”

    • Bert den Uijl says:

      E34 (mine) needed complete overhaul (compressor, evaporator etc.) every 6 years. After 15 years e39, 11 years e61, present F07 and F31, I can say this is one of the issues they managed to leave behind

      • Lynda says:

        If anyone can help me with my air conditioning problem. I’d appreciate it.

        My air con has stopped working all together.. even the fan itself doesn’t blow any air.. making it pretty impossible to drive in Queensland weather.

        Any body gave any suggestions on this issue?

        And… how much it would roughly cost to repair?

        It’s a 2007 BMW 118i

        • Carina van der Westhuizen says:

          I have a BMW e46 aircon blower fan not working – on and off. I suspect the fan motor brushes need replacement. Please help!

    • Costanzo Ciaccia says:

      Luck13 you might want to read that again an notice the n’t that comes after “are” sounds like angry little man day rather than slow news day just calm down take three deep breaths go to the closest mirror in your house have a good long hard look in it an wake up to yourself maybe even give yourself an uppercut then go buy a good pair of glasses an maybe a reading lesson before abusing another article an making yourself sound silly lmao what a tool.

  2. Ava Alice says:

    Nice post. Its very helpful for fix a A.C

  3. Apple Grace says:

    The word “clean” and “maintenance” are closely related together in cleaning your Car Air conditioning System.
    In fact, neither would exist without the other. Just like the human body gets occasionally clogged with toxins, your car’s air conditioner can get bogged down with dirt, hair, pollen, dust, fur, and other small debris when you drive it.

    Nice and detailed blog, well explained.

  4. daddyig says:

    i hv 323ci 2000 and theres a problem with the ac. the ac control panels won’t turn on like there is no electricity. I try to change the fuse but even the fuse is break i tried 3 times with 3 new fuse and still same. I try change the ac control panel but yet, still same doesnt turn on. Anyone had this experience, please help for the info. Tq

  5. Wayne says:

    I have an 07 Z4. Aircon will not turn on at the switch ( does not light up). Fan works. Looked at the fuses and ok. Kwik fit has tested the gases etc and ok.
    Any suggestions and how much?

  6. Jacob H Bristol says:

    My bmwx5 2009 ac is not blowing cold

  7. Gordon Hutton says:

    Hi my 2010 320d has a fishy odour when I switch ac off. I did notice a screenwash / coolant smell when I have car a running temp but lately been using ac and there’s a smell ghat is like smelly socks but I think as engine heats up I get more of a fish smell. Any suggestions please? It’s going in for an antibacterial treatment and ac recharge. I’m wondering if behind the dash theres a small leak which is causing this but honestly just guessing. Any help would be much appreciated.
    Thanks in advance

    • NuMoo says:

      Spray Lysol down into the vents, wait until dry, then spray in to the lower intake, which is used when you have the Air recirculate in to the car, do it on Low until you see the mist come out from the top vent, and stop when ot does. Let the car sit until it is dry. you may need to repeat this 1x/ week for 3-4 weeks. In the Future REMEMBER : shut off the AC and let the blowers dry out the vents before shutting down the car, and try not to recirculate the cabin air for prolonged time.

  8. When it’s not really that hot, would it be better if I just keep the windows open? Or would that ruin my interiors?

  9. ComeAndGitIt says:

    LOL!!!! Misleading title… garbage post…

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