After few hours driving in town with a lot of traffic my AC was working fine, keeping low temperature inside. Then I had to stop the engine for few minutes and when I turned it on, although the AC button was pushed (glows green), the air coming out was hot. It seems to be working (after I press the AC button there is a "click" coming out of the compressor, along with clearly noticeable change in engine sound (slight RPM increse)), but it behaves as if there is no coolant in the system. After I opened the hood to check electrical connections, belts, etc I noticed a lot of small (oily) droplets all over and around the compressor.

The only thing I thought of is if there is some kind of pressure valve releasing the system freon (if the auxiliary fan is not rotating and the temperature is too high or in any other extreme case)?

If anyone has experienced anything similar or has any idea what could be the cause, please share your thoughts.

P.S. The car is BMW E39.

  • 1
    It sounds to me like the compressor lost one of it's seals. – Pᴀᴜʟsᴛᴇʀ2 Jun 6 '15 at 18:58
  • @Paulster2 How could this be checked? – Ziezi Jun 6 '15 at 19:04
  • You'd probably need to take it to a shop. – Pᴀᴜʟsᴛᴇʀ2 Jun 6 '15 at 19:11
  • @Paulster2 is it the bearing seals or anything else? (If you have any schematics of the AC compressor post it as an answer, I've looked but I can't find any detail internal description). – Ziezi Jun 6 '15 at 19:17
  • 1
    Also, you need to verify whether A/C clutch is kicking in. Just run the engine with the hood open and A/C on, watch the main pulley on the compressor ... it will be self evident if the clutch is kicking in. If it's kicking in, you still have refrigerant in the system (it won't run without it). If this is the case, it may be a blend door stuck open. – Pᴀᴜʟsᴛᴇʀ2 Jun 6 '15 at 19:24

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.