AC not cold after working a while
Thread Starter
Driver
Joined: Nov 2018
Posts: 78
Likes: 17
From: tx
AC not cold after working a while
When outside temp is around 90F, after AC is turned on, it feels cold initially. But after 1 hour or so, it only blows cool but not cold air. This is the case for both auto on and off with both side temp control turn down to LO.
The inside of the car feels a bit too warm but not too hot.
After I turn off the engine for 20 min and restart, It repeats that that cold to cool air blowing again. Any idea what could the issue? Thanks.
The inside of the car feels a bit too warm but not too hot.
After I turn off the engine for 20 min and restart, It repeats that that cold to cool air blowing again. Any idea what could the issue? Thanks.
Racer
Joined: Feb 2017
Posts: 1,555
Likes: 345
From: Ontario, Canada
When outside temp is around 90F, after AC is turned on, it feels cold initially. But after 1 hour or so, it only blows cool but not cold air. This is the case for both auto on and off with both side temp control turn down to LO.
The inside of the car feels a bit too warm but not too hot.
After I turn off the engine for 20 min and restart, It repeats that that cold to cool air blowing again. Any idea what could the issue? Thanks.
The inside of the car feels a bit too warm but not too hot.
After I turn off the engine for 20 min and restart, It repeats that that cold to cool air blowing again. Any idea what could the issue? Thanks.
Pit Crew
Joined: Jul 2019
Posts: 248
Likes: 96
From: CO
Does the car make a jet sound in front of the passenger seat when accelerating while the ac is acting up? Freezing usually means that there is too much freon, when the evaporator coil freezes the pressure on the HIGH side will be excessive which will cause excessive noise around the blower motor.
Thread Starter
Driver
Joined: Nov 2018
Posts: 78
Likes: 17
From: tx
Thanks for all reply. The car is 2017 RX. It does not make
Any abnormal noise when the issue happens. I am thinking that the device controlling temp may stuck at say 77F (even I set it to LO). Just a thought.
Thread Starter
Driver
Joined: Nov 2018
Posts: 78
Likes: 17
From: tx
Just some update: I drove the car for a trip for couple of hours. This time, the outside temp was around 95 and i did not find any issue. The ac always below cold air. After I came home, I did some measurement and the outlet temp was around 40F and there is quite bit condensing water coming out from the bottom.
I think there is no issue with compressor or refrigerant. I also tested the temp control and it works for both driver and passenger side. I am thinking that the issue might have something to do with outside temp and humidity so that the evaporator could be frozen and prevented air going through (as suggested by mikemu30). I have previously change the cabin filter with a FRAM filter. Maybe it is different than the OEM one. I think I might get OEM one and change it back.
The car is still under warranty. But without a way to show the issue, I think the dealer can not do much. Anyone has any thought, please let me know. Thanks.
I think there is no issue with compressor or refrigerant. I also tested the temp control and it works for both driver and passenger side. I am thinking that the issue might have something to do with outside temp and humidity so that the evaporator could be frozen and prevented air going through (as suggested by mikemu30). I have previously change the cabin filter with a FRAM filter. Maybe it is different than the OEM one. I think I might get OEM one and change it back.
The car is still under warranty. But without a way to show the issue, I think the dealer can not do much. Anyone has any thought, please let me know. Thanks.
Racer
Joined: Feb 2017
Posts: 1,555
Likes: 345
From: Ontario, Canada
Just some update: I drove the car for a trip for couple of hours. This time, the outside temp was around 95 and i did not find any issue. The ac always below cold air. After I came home, I did some measurement and the outlet temp was around 40F and there is quite bit condensing water coming out from the bottom.
I think there is no issue with compressor or refrigerant. I also tested the temp control and it works for both driver and passenger side. I am thinking that the issue might have something to do with outside temp and humidity so that the evaporator could be frozen and prevented air going through (as suggested by mikemu30). I have previously change the cabin filter with a FRAM filter. Maybe it is different than the OEM one. I think I might get OEM one and change it back.
The car is still under warranty. But without a way to show the issue, I think the dealer can not do much. Anyone has any thought, please let me know. Thanks.
I think there is no issue with compressor or refrigerant. I also tested the temp control and it works for both driver and passenger side. I am thinking that the issue might have something to do with outside temp and humidity so that the evaporator could be frozen and prevented air going through (as suggested by mikemu30). I have previously change the cabin filter with a FRAM filter. Maybe it is different than the OEM one. I think I might get OEM one and change it back.
The car is still under warranty. But without a way to show the issue, I think the dealer can not do much. Anyone has any thought, please let me know. Thanks.
If you do end up at the dealer change that cabin filter back to OEM or else you may feel like a ping-pong ball
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Thread Starter
Driver
Joined: Nov 2018
Posts: 78
Likes: 17
From: tx
Today, I connected my OBD II WIFI scanner and checked "Evaporator Fin Thermistor" reading. It appears working and stayed at 32F after 10-15 min of running. It is supposed to control the cycle of AC so that the fin will not get frozen. But I think 32F is a bit on the boundary of getting frozen. I am thinking a slight change such as the cabin filter may change the equation. Thanks.
Thread Starter
Driver
Joined: Nov 2018
Posts: 78
Likes: 17
From: tx
It happened again two days ago when driving in high way after around 1 hour. This time I got enough evidences toward evaporator iced up problem:
1. When it happens, the out let air flow reduced noticeably.
2. After turning off the car for 15-20 min, the issue is gone, but will come back after another 1 hour or so.
3. Keep fan high blowing speed will avoid the issue (but will not resolve the issue if the problem already occurs).
4. After stopping the car, it seems to drain a lot of condensation water (more than a normal case).
I've sent the car to the dealer. Not sure what can cause that. Thanks,
1. When it happens, the out let air flow reduced noticeably.
2. After turning off the car for 15-20 min, the issue is gone, but will come back after another 1 hour or so.
3. Keep fan high blowing speed will avoid the issue (but will not resolve the issue if the problem already occurs).
4. After stopping the car, it seems to drain a lot of condensation water (more than a normal case).
I've sent the car to the dealer. Not sure what can cause that. Thanks,
Racer
Joined: Feb 2017
Posts: 1,555
Likes: 345
From: Ontario, Canada
It happened again two days ago when driving in high way after around 1 hour. This time I got enough evidences toward evaporator iced up problem:
1. When it happens, the out let air flow reduced noticeably.
2. After turning off the car for 15-20 min, the issue is gone, but will come back after another 1 hour or so.
3. Keep fan high blowing speed will avoid the issue (but will not resolve the issue if the problem already occurs).
4. After stopping the car, it seems to drain a lot of condensation water (more than a normal case).
I've sent the car to the dealer. Not sure what can cause that. Thanks,
1. When it happens, the out let air flow reduced noticeably.
2. After turning off the car for 15-20 min, the issue is gone, but will come back after another 1 hour or so.
3. Keep fan high blowing speed will avoid the issue (but will not resolve the issue if the problem already occurs).
4. After stopping the car, it seems to drain a lot of condensation water (more than a normal case).
I've sent the car to the dealer. Not sure what can cause that. Thanks,
Thread Starter
Driver
Joined: Nov 2018
Posts: 78
Likes: 17
From: tx
Intermediate
Joined: Sep 2020
Posts: 379
Likes: 267
From: Florida
See No. 4 in this link: https://trustcompleteair.com/frozen-...r-coil-causes/
