C5 ac
Thread Starter
4th Gear
Joined: May 2010
Posts: 4
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C5 ac
My ac was freezing up on the road at 75 to 80 in about 90 mins. and then when I stoped for 20 mins. it was ok again,any idea of what can be?
Last edited by lowride; Jul 14, 2012 at 03:42 PM. Reason: did not finish
Racer
Joined: Feb 2004
Posts: 359
Likes: 7
From: St. Paul MN
How do you know it was freezing up? The aluminum line going to the firewall was iced over, or airflow was restricted to the vents?
If this is a recent symptom and no services were done to your HVAC system recently, you may have a refrigerant leak.
Usually icing is caused by refrigerant undercharge, causing the coils to dip below freezing point. Normally the coils should be above freezing near 40. In your case when humid air passes across the coil, the moisture condenses and then freezes. When you stop (or turn the A/C off and leave the fan on) the ice melts, and you restart the cycle.
If you DIY, get an HVAC gauge to check your low and high pressure settings. There is a chart in the service manual that correlates outdoor air temp & humidity to the proper low and high side pressure ranges. It also has troubleshooting steps in case one pressure is within range and the other not, which can pinpoint the fault. Tracking down and repairing your leak can be a challenge for DIY.
A simpler route is bring it to a shop that will drain refrigerant, locate/repair the leak or failed components, and recharge to the proper amount.
Todd
If this is a recent symptom and no services were done to your HVAC system recently, you may have a refrigerant leak.
Usually icing is caused by refrigerant undercharge, causing the coils to dip below freezing point. Normally the coils should be above freezing near 40. In your case when humid air passes across the coil, the moisture condenses and then freezes. When you stop (or turn the A/C off and leave the fan on) the ice melts, and you restart the cycle.
If you DIY, get an HVAC gauge to check your low and high pressure settings. There is a chart in the service manual that correlates outdoor air temp & humidity to the proper low and high side pressure ranges. It also has troubleshooting steps in case one pressure is within range and the other not, which can pinpoint the fault. Tracking down and repairing your leak can be a challenge for DIY.
A simpler route is bring it to a shop that will drain refrigerant, locate/repair the leak or failed components, and recharge to the proper amount.
Todd
