2002 BMW X5 Replacing AC Condensor Did Not Work

Tiny
LARSENS
  • MEMBER
  • 2002 BMW X5
  • 6 CYL
  • AWD
  • AUTOMATIC
  • 88,000 MILES
Repair shop replaced the AC condensor after the car would only blow warm air. Now on long drives (over 2 hours) the system seems to radiate cool air but will not blow it. Makes me wonder if the system is frozen up or something. Are there controls to baffles that might malfunction or a clutch that would work only when the system is beginning to cool but not later on? Shop can't/won't diagnose the problem since it works fine when we take it to the shop after a short drive. We spent a TON of money on the condensor and don't want to pay for a fishing expedition, dismantling the dashboard again, etc. Without a specific idea of where to direct the repairs. Any ideas on why this new problem would arise? Would be happy to discuss further. Thanks.
Do you
have the same problem?
Yes
No
Monday, July 27th, 2009 AT 4:07 PM

4 Replies

Tiny
LARSENS
  • MEMBER
Your reply deals with lean fuel condition but my question was regarding an Air Conditioning problem. I saw some of your other AC replies on BMWs and you appear to really know your stuff. Can you reply to my AC question? You can hear the AC system working and apparently the fan, and it cools OK for a couple hours but then seems to not push any air through the dash despite the noise. Advice? I saw your earlier posts about a final stage unit or motor for the blend air door. Would those things work for awhile and then quit?
Was this
answer
helpful?
Yes
No
Wednesday, July 29th, 2009 AT 10:06 AM
Tiny
RASMATAZ
  • MEMBER
An A/C system that blows cold air for awhile then warm air is probably freezing up. This can be caused by air and moisture in the system that allows ice to form and block the orifice tube.

Evacuating the system with a vacuum pump will purge it of unwanted air and moisture. Evacuation should be done with a vacuum pump that is capable of achieving and holding a high vacuum (29 inches) for at least 30 to 45 minutes.

For best performance, an A/C system should contain less than 2% air by weight. For every 1% increase in the amount of air that displaces refrigerant in the system, there will be a corresponding drop of about one degree in cooling performance. More than 6% air can cause a very noticeable drop in cooling performance, and possibly cause evaporator freeze-up.

Air can get inside a system through leaks, by not evacuating the system prior to recharging it, and/or by recharging the system with refrigerant that is contaminated with air. Recovery equipment can suck air into the recycling tank if an A/C system contains air or if the system has a leak. For this reason, the refrigerant recovery tank on recycling equipment must be checked and purged daily. On some equipment, this is done automatically. But on equipment that lacks an automatic purge cycle, tank pressure and temperature has to be measured and compared to a static pressure reference chart.

Some refrigerant identifier equipment can detect air in the system as well as other contaminants. An identifier should be used to check the refrigerant before the system is serviced to prevent cross-contamination of recovery and recycling equipment.

Possible causes of intermittent cooling in a manual A/C system that might be caused by an electrical problem include:

Faulty low pressure cutout switch. This switch prevents the compressor from running if the refrigerant level is low. If the cutout switch is not reading correctly, it can prevent the compressor from coming on.

Faulty compressor clutch. The magnetic clutch on the compressor requires full battery voltage to engage. If the voltage to the clutch is low, or the clutch coils have too much resistance, or the air gap in the clutch is too great, the clutch may not engage to drive the compressor.

Faulty compressor clutch relay. Check to see if the relay is receiving voltage when the A/C is turned on. Also check the relay wiring and ground connections. If bypassing the relay with a jumper wire or routing battery voltage directly to the compressor clutch makes the A/C work, the relay is probably bad.

Faulty A/C control switch. The switch may be worn and not making good contact when it is turned on.

Some possible causes of intermittent cooling (or no cooling) on automatic A/C systems include all of the above, plus:

A problem in the control module or control head (this usually requires using a dealer scan tool to read fault codes and perform self-diagnostics).

A bad temperature sensor (an ambient air temperature sensor, interior air temperature sensor, evaporator temperature sensor, or sunload sensor). Again, a factory scan tool is usually required to perform diagnostics on the system.
Was this
answer
helpful?
Yes
No
Wednesday, July 29th, 2009 AT 11:45 AM
Tiny
LARSENS
  • MEMBER
Thanks for the fantastic information. I suspected it might be freezing up. It also blew fog for awhile after the condensor was installed and it had been recharged and that might have been an indication of moisture in the system. I will ask the shop to evacuate and recharge the system again.
Was this
answer
helpful?
Yes
No
Wednesday, July 29th, 2009 AT 2:11 PM
Tiny
DR. HAGERTY
  • MEMBER
The E-53 tends to be sensitive to refrigerant amount so that any shortfall is systemically amplified. Be sure the correct amount of R-134 is in the system and the right amount of oil too.
Was this
answer
helpful?
Yes
No
Sunday, August 2nd, 2009 AT 4:42 PM

Please login or register to post a reply.

Recommended Guides