Lukewarm AC
Thread Starter
Pro
Joined: Dec 2005
Posts: 621
Likes: 2
From: Stillwater Minnesota
Lukewarm AC
My AC seems to be performing poorly. I'm not sure if it's cause I moved to AZ or what.
When I turn it on I get lukewarm air. I checked the high and low pressures. High side is above the low side. Checked for leaks. There are no leaks.
The passenger side has nice and cool air but the driver side has the lukewarm air. Although both sides are not as cool as I would expect.
Any ideas? I had actually thought I would see a greater difference in pressure between high and low sides though. Do you guys know what a nominal pressure reading would be?
Thanks!
When I turn it on I get lukewarm air. I checked the high and low pressures. High side is above the low side. Checked for leaks. There are no leaks.
The passenger side has nice and cool air but the driver side has the lukewarm air. Although both sides are not as cool as I would expect.
Any ideas? I had actually thought I would see a greater difference in pressure between high and low sides though. Do you guys know what a nominal pressure reading would be?
Thanks!
Pro
Joined: Sep 2007
Posts: 735
Likes: 7
From: Bucks County Pa
AC Pressures
Hi, below are some optimum pressures at different temps. All are at 2000rpm which is the best rpm to charge a system at. The lower # is the low side, higher # is high side, and the last # is the maxium,(temps may be lower), center vent temp at those pressures. All are at 70% humidity.Different humidity's make a small difference. The system capacity is 1.75 lbs.
70 deg--30psig, 185psig, 50d
80 deg--34psig, 245psig, 58d
90 deg--38psig, 305psig, 65d
100 deg-44psig, 365psig, 75d
Good Luck
Below is a chart from the service manual. The service manual uses idle speeds.
+++++++++++++++++++++++++++++++++++++
A/C Performance Table Ambient Air Temperature
Relative Humidity
Service Port Pressure
Maximum Left Center Discharge Air Temperature
Low Side
High Side
13-18°C (55-65°F)---Ambient Temp
0-100%--- Humidity
211-241 kPa (31-35 psi)--Low Side
500-740 kPa (73-107 psi)---High Side
8°C (46°F)--- Maxium Center vent temp
19-23°C (66-75°F)
Below 40%
193-223 kPa (28-32 psi)
780-1090 kPa (106-167 psi)
8°C (46°F)
Above 40%
209-239 kPa (30-35 psi)
730-1050 kPa (106-167 psi)
9°C (48°F)
24-29°C (76-85°F)
Below 35%
172-214 kPa (25-31 psi)
1020-1227 kPa (148-178 psi)
9°C (48°F)
35-60%
199-229 kPa (29-33 psi)
970-1300 kPa (141-189 psi)
9°C (48°F)
Above 60%
207-237 kPa (30-34 psi)
1020-1500 kPa (148-218 psi)
10°C (50°F)
30-35°C (86-95°F)
Below 30%
210-240 kPa (31-35 psi)
1130-1520 kPa (164-221 psi)
10°C (50°F)
30-50%
208-238 kPa (30-35 psi)
1190-1670 kPa (173-242 psi)
11°C (52°F)
Above 50%
205-235 kPa (30-35 psi)
1280-1910 kPa (186-277 psi)
11°C (52°F)
36-40°C (96-105°F)
Below 20%
226-256 kPa (33-37 psi)
1280-1650 kPa (186-240 psi)
12°C (54°F)
20-40%
218-248 kPa (32-36 psi)
1360-1870 kPa (197-271 psi)
12°C (54°F)
Above 40%
211-241 kPa (31-35 psi)
1520-2100 kPa (221-305 psi)
12°C (54°F)
41-46°C (106-115°F)
Below 20%
238-268 kPa (35-39 psi)
1460-1830 kPa (212-267 psi)
13°C (55°F)
Above 20%
226-256 kPa (33-37 psi)
1570-2100 kPa (228-306 psi)
13°C (55°F)
47-49°C (116-120°F)
Below 30%
238-268 kPa (35-39 psi)
1750-2090 kPa (254-303 psi)
14°C (57°F)
70 deg--30psig, 185psig, 50d
80 deg--34psig, 245psig, 58d
90 deg--38psig, 305psig, 65d
100 deg-44psig, 365psig, 75d
Good Luck
Below is a chart from the service manual. The service manual uses idle speeds.
+++++++++++++++++++++++++++++++++++++
A/C Performance Table Ambient Air Temperature
Relative Humidity
Service Port Pressure
Maximum Left Center Discharge Air Temperature
Low Side
High Side
13-18°C (55-65°F)---Ambient Temp
0-100%--- Humidity
211-241 kPa (31-35 psi)--Low Side
500-740 kPa (73-107 psi)---High Side
8°C (46°F)--- Maxium Center vent temp
19-23°C (66-75°F)
Below 40%
193-223 kPa (28-32 psi)
780-1090 kPa (106-167 psi)
8°C (46°F)
Above 40%
209-239 kPa (30-35 psi)
730-1050 kPa (106-167 psi)
9°C (48°F)
24-29°C (76-85°F)
Below 35%
172-214 kPa (25-31 psi)
1020-1227 kPa (148-178 psi)
9°C (48°F)
35-60%
199-229 kPa (29-33 psi)
970-1300 kPa (141-189 psi)
9°C (48°F)
Above 60%
207-237 kPa (30-34 psi)
1020-1500 kPa (148-218 psi)
10°C (50°F)
30-35°C (86-95°F)
Below 30%
210-240 kPa (31-35 psi)
1130-1520 kPa (164-221 psi)
10°C (50°F)
30-50%
208-238 kPa (30-35 psi)
1190-1670 kPa (173-242 psi)
11°C (52°F)
Above 50%
205-235 kPa (30-35 psi)
1280-1910 kPa (186-277 psi)
11°C (52°F)
36-40°C (96-105°F)
Below 20%
226-256 kPa (33-37 psi)
1280-1650 kPa (186-240 psi)
12°C (54°F)
20-40%
218-248 kPa (32-36 psi)
1360-1870 kPa (197-271 psi)
12°C (54°F)
Above 40%
211-241 kPa (31-35 psi)
1520-2100 kPa (221-305 psi)
12°C (54°F)
41-46°C (106-115°F)
Below 20%
238-268 kPa (35-39 psi)
1460-1830 kPa (212-267 psi)
13°C (55°F)
Above 20%
226-256 kPa (33-37 psi)
1570-2100 kPa (228-306 psi)
13°C (55°F)
47-49°C (116-120°F)
Below 30%
238-268 kPa (35-39 psi)
1750-2090 kPa (254-303 psi)
14°C (57°F)
Last edited by bestvettever; Aug 1, 2009 at 12:21 AM.
Thread Starter
Pro
Joined: Dec 2005
Posts: 621
Likes: 2
From: Stillwater Minnesota
Thanks! Here's what I'm seeing....
Static before starting car... 75psi / 75psi
Max AC @ idle... 27psi / 240psi
I watch the high side slowly climb to 240psi valve opens (or whatever it is) low side stays at 27psi and high drops pretty quickly (perhaps within 5seconds) to 150psi then starts to climb again.
Ambient temperature is around 100* F. Air coming out is just lukewarm though.
That would be closest to your chart here--->
36-40°C (96-105°F)
Below 20%
226-256 kPa (33-37 psi)
1280-1650 kPa (186-240 psi)
12°C (54°F)
20-40%
218-248 kPa (32-36 psi)
1360-1870 kPa (197-271 psi)
12°C (54°F)
Above 40%
211-241 kPa (31-35 psi)
1520-2100 kPa (221-305 psi)
12°C (54°F)
Static before starting car... 75psi / 75psi
Max AC @ idle... 27psi / 240psi
I watch the high side slowly climb to 240psi valve opens (or whatever it is) low side stays at 27psi and high drops pretty quickly (perhaps within 5seconds) to 150psi then starts to climb again.
Ambient temperature is around 100* F. Air coming out is just lukewarm though.
That would be closest to your chart here--->
36-40°C (96-105°F)
Below 20%
226-256 kPa (33-37 psi)
1280-1650 kPa (186-240 psi)
12°C (54°F)
20-40%
218-248 kPa (32-36 psi)
1360-1870 kPa (197-271 psi)
12°C (54°F)
Above 40%
211-241 kPa (31-35 psi)
1520-2100 kPa (221-305 psi)
12°C (54°F)
Pro
Joined: Sep 2007
Posts: 735
Likes: 7
From: Bucks County Pa
AC recharge
Hi, you are low on refrigerant. If you know the car and it's history, and know that it has not been completely discharged, or charged improperly in the past then recharge at 2000 rpm.s with ref 134 + oil, using these pressures, 100 deg-44psig, 365psig, 75d, the 75d center vent temp is maxium , you will probably see 45 to 60 in real life. If you are not sure of the past history, it is best to evacuate the system, pull a vacuum of 29" for an hour or more, and then recharge with 1.75 lbs of r134 with about 4oz of added oil. It will be nice and cold at those pressures. Also don't forget to check the condenser for dirt, leaves and debris clogging the fins, a good flush with a garden hose from the back, (between the rad and cond), will assure a good airflow.
Good Luck
Good Luck
Thread Starter
Pro
Joined: Dec 2005
Posts: 621
Likes: 2
From: Stillwater Minnesota
Oh wow... greatly appreciated. I tried to add refrigerant using my presure gauge setup. Low connected to low side, high connected to high side, service port connected to can of refrigerant. Then I opened the low side port. However, when idling with A/C on max the system would not take any refrigerant. I was perplexed...
I've had the car for 3 years. I got it with 86k miles on it. Now it has 94k miles on it. Have ran AC consistently every few months (even in winter) with no issues what so ever until now. System shows no signs of leaks (I performed a leak, and pressure test).
I think I'll try to add more refrigerant but this time using your advice and reving engine to 2k rpm.
Thanks!
I've had the car for 3 years. I got it with 86k miles on it. Now it has 94k miles on it. Have ran AC consistently every few months (even in winter) with no issues what so ever until now. System shows no signs of leaks (I performed a leak, and pressure test).
I think I'll try to add more refrigerant but this time using your advice and reving engine to 2k rpm.
Thanks!
Melting Slicks
Joined: Feb 2007
Posts: 3,266
Likes: 8
From: Indian Rocks Beach FL
St. Jude Donor '08-'09-'10
I just took my car in today for the same symptoms as your car. It was 6 ounces low on refrigerant. It's like a new car now, darn near froze me out coming home! 
Pro
Joined: Sep 2007
Posts: 735
Likes: 7
From: Bucks County Pa
AC Tricks
Oh wow... greatly appreciated. I tried to add refrigerant using my presure gauge setup. Low connected to low side, high connected to high side, service port connected to can of refrigerant. Then I opened the low side port. However, when idling with A/C on max the system would not take any refrigerant. I was perplexed...
I've had the car for 3 years. I got it with 86k miles on it. Now it has 94k miles on it. Have ran AC consistently every few months (even in winter) with no issues what so ever until now. System shows no signs of leaks (I performed a leak, and pressure test).
I think I'll try to add more refrigerant but this time using your advice and reving engine to 2k rpm.
Thanks!
I've had the car for 3 years. I got it with 86k miles on it. Now it has 94k miles on it. Have ran AC consistently every few months (even in winter) with no issues what so ever until now. System shows no signs of leaks (I performed a leak, and pressure test).
I think I'll try to add more refrigerant but this time using your advice and reving engine to 2k rpm.
Thanks!
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Thread Starter
Pro
Joined: Dec 2005
Posts: 621
Likes: 2
From: Stillwater Minnesota
Seems the problem reared it's ugly head again.
I'm curious. This all started happening when I moved to Arizona. I wonder if since this isn't a daily driver that the seals are taking a beating in the insanely dry weather.
I'm going to charge it again and see what happens. My static pressures are at around 50 psi when previously they were at 75 psi.
I guess my question is this. I've got a can of AC leak sealer in my garage. I'm very reluctant to use it for fear of what it might do to the expansion valve.
Has anybody used leak sealer before on their A/C system?
I'm curious. This all started happening when I moved to Arizona. I wonder if since this isn't a daily driver that the seals are taking a beating in the insanely dry weather.
I'm going to charge it again and see what happens. My static pressures are at around 50 psi when previously they were at 75 psi.
I guess my question is this. I've got a can of AC leak sealer in my garage. I'm very reluctant to use it for fear of what it might do to the expansion valve.
Has anybody used leak sealer before on their A/C system?
Safety Car
Joined: May 2008
Posts: 4,237
Likes: 11
From: Lacombe Louisiana
The a/c system is about the same as any modern car.Any seal or o-ring can start leaking.If you do not have a GOOD leak detector you may try adding some leak check (dye) and try finding your leak that way.Otherwise take it to a trusted pro and ask to be SHOWN the leak before repairs. Do NOT add sealer to the system!
Melting Slicks
Joined: Jul 2006
Posts: 2,332
Likes: 31
From: Silver Spring MD
Besides low freon might be the $5 orfice tube on the right fender
Had poor cooling even after I cleaned the condenser, evacuated and recharged the system. Was the little plastic orfice tube in the bulge in the high pressure line on the right front fender.
Mine was so jammed in there had to use needle nose locking vise grips and pray as I twisted the sucker out. Added a little refrigerant oil too as it was bone dry. Need to discharge before removing single bolt holding the tubing together where the orfice tube is located.
Mine was so jammed in there had to use needle nose locking vise grips and pray as I twisted the sucker out. Added a little refrigerant oil too as it was bone dry. Need to discharge before removing single bolt holding the tubing together where the orfice tube is located.
