Front AC colder with the rear AC on
06-08-2022, 06:23 PM
#1
Rennlist Member
Thread Starter
Front AC colder with the rear AC on
I had an 89 S4 here recently for some major work after it suffered TBF.
One of the things we addressed was replacing the AC compressor and lines with Griffith's sourced parts.
Had the system flushed and evacuated and handed off to my AC guru.
I tested it before the hand off and seemed ok to me.
Got a call from my client that AC was not blowing cold enough. But, when he turned on the rear AC the front AC got colder.
I can not explain that. Can anybody?
One of the things we addressed was replacing the AC compressor and lines with Griffith's sourced parts.
Had the system flushed and evacuated and handed off to my AC guru.
I tested it before the hand off and seemed ok to me.
Got a call from my client that AC was not blowing cold enough. But, when he turned on the rear AC the front AC got colder.
I can not explain that. Can anybody?
06-08-2022, 09:27 PM
#3
Rennlist Member
Thread Starter
Repeatable. Strange.
06-09-2022, 02:31 PM
#5
Team Owner
Whats might be happening is that the front evaporator is icing up,
this reduces the cooling capability thus the rear unit will be colder .
as a test after this occurs park the car with the engine off for about 10 mins then turn on the system.
the front should be much colder also note how much water drains onto the floor.
A humid area with have this event happen faster
Solution is to replace the freeze switch.
NOTE also check the drier window to see how much bubbles you see,
if close to none then you have close to fully charged system.
this reduces the cooling capability thus the rear unit will be colder .
as a test after this occurs park the car with the engine off for about 10 mins then turn on the system.
the front should be much colder also note how much water drains onto the floor.
A humid area with have this event happen faster
Solution is to replace the freeze switch.
NOTE also check the drier window to see how much bubbles you see,
if close to none then you have close to fully charged system.
The following users liked this post:
mkhargrove (06-13-2022)
06-09-2022, 03:54 PM
#6
Rennlist Member
Thread Starter
What might be happening is that the front evaporator is icing up,
this reduces the cooling capability thus the rear unit will be colder .
as a test after this occurs park the car with the engine off for about 10 mins then turn on the system.
the front should be much colder also note how much water drains onto the floor.
A humid area with have this event happen faster
Solution is to replace the freeze switch.
NOTE also check the drier window to see how much bubbles you see,
if close to none then you have close to fully charged system.
this reduces the cooling capability thus the rear unit will be colder .
as a test after this occurs park the car with the engine off for about 10 mins then turn on the system.
the front should be much colder also note how much water drains onto the floor.
A humid area with have this event happen faster
Solution is to replace the freeze switch.
NOTE also check the drier window to see how much bubbles you see,
if close to none then you have close to fully charged system.
Kevin
06-12-2022, 01:35 PM
#7
Rennlist Member
Whats might be happening is that the front evaporator is icing up,
this reduces the cooling capability thus the rear unit will be colder .
as a test after this occurs park the car with the engine off for about 10 mins then turn on the system.
the front should be much colder also note how much water drains onto the floor.
A humid area with have this event happen faster
Solution is to replace the freeze switch.
NOTE also check the drier window to see how much bubbles you see,
if close to none then you have close to fully charged system.
this reduces the cooling capability thus the rear unit will be colder .
as a test after this occurs park the car with the engine off for about 10 mins then turn on the system.
the front should be much colder also note how much water drains onto the floor.
A humid area with have this event happen faster
Solution is to replace the freeze switch.
NOTE also check the drier window to see how much bubbles you see,
if close to none then you have close to fully charged system.
Trending Topics
06-13-2022, 03:06 AM
#8
Rennlist Member
^^ They also wear out. There is a brass diaphragm inside that can crack and leak out the capillary fluid.
With how old they are fitting a new one might be a more reliable thing to do.
With how old they are fitting a new one might be a more reliable thing to do.
06-14-2022, 07:38 PM
#9
Team Owner
Last freeze switch i bought was about 25.00
06-16-2022, 08:17 PM
#10
Rennlist Member
They can get overloaded if there is too much current draw and burn out too.
You may need to adjust it after installation so that it shuts things off correctly...my new one needed adjustment (there is a screw on the opposite side of where the wires connect, or a screw right where they are...depending on which kind you get); it wasn't shutting off and the evap. was freezing up.....make sure when installing you don't put a kink in the capillary tube...there's more than is needed so mine I looped.
There is a "cap" that fits over the end of the probe that goes into the hole where the evaporator is....keeps the probe from being installed too deeply...make sure to move that over to your new probe.
You may need to adjust it after installation so that it shuts things off correctly...my new one needed adjustment (there is a screw on the opposite side of where the wires connect, or a screw right where they are...depending on which kind you get); it wasn't shutting off and the evap. was freezing up.....make sure when installing you don't put a kink in the capillary tube...there's more than is needed so mine I looped.
There is a "cap" that fits over the end of the probe that goes into the hole where the evaporator is....keeps the probe from being installed too deeply...make sure to move that over to your new probe.
The following users liked this post:
Speedtoys (06-16-2022)
07-23-2022, 10:16 AM
#11
dual evap cars share the same single condenser. When you say colder do you mean overall cockpit or the front vents? Most common Shark issue
is air mixture up front; could be fresh air flap stuck open due to failed vacuum actuator or the blend flap.