How long should the AC run for?
Thread Starter
Senior Member
Joined: Nov 2013
Posts: 323
Likes: 4
From: Los Angeles, CA. USA
2013 c250
How long should the AC run for?
The a/c in my ride runs cool and the sweet spot is b/w 3 and 4 on the dial. BUT after around 2 hours it gets ****ty so on an 8 hour trip I find myself blasting it all the way, and it's still cold- but it's not blowing that fast- it's still cold though, but it's the equivalent to maybe 1 on the dial. What gives?
Super Member
Joined: Jul 2009
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2021 Yukon XL Denali, 2017 GLS450 4MATIC, 1993 Chevy Corvette
The a/c in my ride runs cool and the sweet spot is b/w 3 and 4 on the dial. BUT after around 2 hours it gets ****ty so on an 8 hour trip I find myself blasting it all the way, and it's still cold- but it's not blowing that fast- it's still cold though, but it's the equivalent to maybe 1 on the dial. What gives?
Super Member
Joined: Nov 2009
Posts: 724
Likes: 31
Car free at the moment
Sounds to me like your evaporator is freezing up. Can you hear the fan running but little or no air is coming out the vents? If so that's because the avaporator is covered in ice, blocking the airflow. It shouldn't do this, but it's an easy fix. Just hit the ac button to turn off the compressor. Leave the hvac system running in vent mode. As the ice melts the airflow will increase and warm up. Then you can switch the ac back on and be good for another two hours.
There are a couple of things that can cause the evaporate to freeze over so can't diagnose it here. But it's a common symptom of being a little bit low on refrigerant.
There are a couple of things that can cause the evaporate to freeze over so can't diagnose it here. But it's a common symptom of being a little bit low on refrigerant.
Member
Joined: Jan 2007
Posts: 97
Likes: 4
From: Malaysia
W203 (2007), W120 (1962)
Is your a/c set on AUTO mode?
The fan speed will slow down once the desired temp is reached.
That is what mine does.
If I want the normal set speed of the a/c, I have to off the Auto.
Shan.
The fan speed will slow down once the desired temp is reached.
That is what mine does.
If I want the normal set speed of the a/c, I have to off the Auto.
Shan.
Thread Starter
Senior Member
Joined: Nov 2013
Posts: 323
Likes: 4
From: Los Angeles, CA. USA
2013 c250
Sounds to me like your evaporator is freezing up. Can you hear the fan running but little or no air is coming out the vents? If so that's because the avaporator is covered in ice, blocking the airflow. It shouldn't do this, but it's an easy fix. Just hit the ac button to turn off the compressor. Leave the hvac system running in vent mode. As the ice melts the airflow will increase and warm up. Then you can switch the ac back on and be good for another two hours.
There are a couple of things that can cause the evaporate to freeze over so can't diagnose it here. But it's a common symptom of being a little bit low on refrigerant.
There are a couple of things that can cause the evaporate to freeze over so can't diagnose it here. But it's a common symptom of being a little bit low on refrigerant.
