• Mustang Forums
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • Fox 5.0 Mustang Tech

Engine AC blowing cool not cold

  • Thread starter Thread starter 93CalypsoConvert
  • Start date Start date Jun 5, 2021
  • Tags Tags
    a/c air conditioner

93CalypsoConvert

Active Member
Nov 26, 2020
275
91
38
Virginia
Jun 5, 2021
#1
  • Jun 5, 2021
  • #1
I installed a 5.0Resto r-134a kit for 87-93 mustangs. Made sure system was prepared (flushed evaporator core, oiled everything, pulled and held vacuum, continued vacuum for additional 45 min), then I charged with the required 24oz of 134a, but the thing will only blow cool, but not cold (vent thermometer says 60 degrees). Also, the compressor never cycles off, it puts a substantial load on the engine, and makes the whole car run about 30 degrees hotter. Is there too much refrigerant in the system? Bad compressor? I doubt its an orifice tube issue since everything was flushed or new. I am not sure what to do here.
 

nickyb

I gotta say i never painted my nuts, Never Ever
15 Year Member
Apr 3, 2009
2,979
1,623
153
nevada
Jun 5, 2021
#2
  • Jun 5, 2021
  • #2
A set of gauges will help tell you what it is. H.F. Has a cheap set.I personally used e.s.12a and years later I still get below 40 degrees and that is here in Nevada,aka surface of the sun.
 

Potomus Pete

I'm still waiting for the fully nude shots
5 Year Member
Mar 7, 2019
3,308
1,223
153
Sarasota Florida
Jun 5, 2021
#3
  • Jun 5, 2021
  • #3
Frosty Cool 12a would do it...Or you didn't clean enough...I did mine, but didn't clean enough.Has to be super clean. See if your orafice freezes up
 

KRUISR

10 Year Member
Apr 16, 2015
1,803
903
143
Jun 6, 2021
#4
  • Jun 6, 2021
  • #4
Is your fan moving enough air across the condensor?
 
Reactions: 93CalypsoConvert

93CalypsoConvert

Active Member
Nov 26, 2020
275
91
38
Virginia
Jun 6, 2021
#5
  • Jun 6, 2021
  • #5
nickyb said:
A set of gauges will help tell you what it is. H.F. Has a cheap set.I personally used e.s.12a and years later I still get below 40 degrees and that is here in Nevada,aka surface of the sun.
Click to expand...
Ok re-rented the gauges I used when filling the system...

Here is my static pressure at 80 degrees:


Here is my running temps... Low side stayed between 30 and 40 but high side jumped to 210 but kept climbing and climbing until I shut it off at 340.


Here is what the vent was saying:


I have no clue what to make of these numbers... Really hope its just overcharged

Ran the system for about 10 minutes at 1100 rpm with my massive shop fan at full blast blowing into condenser.
 

93CalypsoConvert

Active Member
Nov 26, 2020
275
91
38
Virginia
Jun 6, 2021
#6
  • Jun 6, 2021
  • #6
KRUISR said:
Is your fan moving enough air across the condensor?
Click to expand...
Most likely... Doesn't seem to make a difference if idling, driving, or having my big shop fan blow into it.
 

KRUISR

10 Year Member
Apr 16, 2015
1,803
903
143
Jun 6, 2021
#7
  • Jun 6, 2021
  • #7
Stock fan or electric? What type/style of rad?
 

93CalypsoConvert

Active Member
Nov 26, 2020
275
91
38
Virginia
Jun 6, 2021
#8
  • Jun 6, 2021
  • #8
KRUISR said:
Stock fan or electric? What type/style of rad?
Click to expand...
Electric fan, aluminum rad.
 

KRUISR

10 Year Member
Apr 16, 2015
1,803
903
143
Jun 6, 2021
#9
  • Jun 6, 2021
  • #9
Maybe dump question, is fan running with A/C on?
 

93CalypsoConvert

Active Member
Nov 26, 2020
275
91
38
Virginia
Jun 6, 2021
#10
  • Jun 6, 2021
  • #10
KRUISR said:
Maybe dump question, is fan running with A/C on?
Click to expand...
Yes
 

Potomus Pete

I'm still waiting for the fully nude shots
5 Year Member
Mar 7, 2019
3,308
1,223
153
Sarasota Florida
Jun 6, 2021
#11
  • Jun 6, 2021
  • #11
Need to use 12a or ES12a.
 

93CalypsoConvert

Active Member
Nov 26, 2020
275
91
38
Virginia
Jun 6, 2021
#12
  • Jun 6, 2021
  • #12
Potomus Pete said:
Need to use 12a or ES12a.
Click to expand...
Its an overhaul kit designed for r134a only. Others have had successful results using 134a. Not going to use an alternative refrigerant.
 

Potomus Pete

I'm still waiting for the fully nude shots
5 Year Member
Mar 7, 2019
3,308
1,223
153
Sarasota Florida
Jun 6, 2021
#13
  • Jun 6, 2021
  • #13
I have been through exactly what your doing...We will see what happens. Let us know
 

93CalypsoConvert

Active Member
Nov 26, 2020
275
91
38
Virginia
Jun 6, 2021
#14
  • Jun 6, 2021
  • #14
Update: Tested the system and while running some water over condenser to cool it. Pressure went back down to where it should be so my problem was airflow across it. Went out and bought an auxiliary fan and mounted it to the condenser. Set it up on a relay to activate off the compressor clutch. Blows 37 degrees out the vents now.
 
Last edited: Jun 7, 2021
Reactions: jrichker

Mustang5L5

That is…until I whipped out my Bissell
Mod Dude
Feb 18, 2001
43,215
17,899
224
Massachusetts
Jun 8, 2021
#15
  • Jun 8, 2021
  • #15
93CalypsoConvert said:
Update: Tested the system and while running some water over condenser to cool it. Pressure went back down to where it should be so my problem was airflow across it. Went out and bought an auxiliary fan and mounted it to the condenser. Set it up on a relay to activate off the compressor clutch. Blows 37 degrees out the vents now.
Click to expand...

glad you found it. I was going to chime in when I saw your pressures and say that there are typically too causes of a low side pressure being too low, and hugh side being too high. One is overcharged, which I don’t think you were. Second is poor airflow through the condenser.
 
You must log in or register to reply here.

Similar threads

B
2001 v6 New compressor issue
  • badmech
  • Apr 30, 2026
  • SN95 V6 Mustang Tech
Replies
0
Views
73
SN95 V6 Mustang Tech Apr 30, 2026
badmech
B
B
A/C Issues
  • Boats90GT
  • Jun 10, 2026
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
Replies
2
Views
75
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- Jun 11, 2026
Mcmahst
G
2005 Mustang GT AC cycling on and off every minute
  • GeorgeSwadling
  • Jul 12, 2025
  • 2005 - 2009 Specific Tech
Replies
0
Views
193
2005 - 2009 Specific Tech Jul 12, 2025
GeorgeSwadling
G
M
Progress Thread mnky99 2001 V6 evap core, ac compressor, heater core replacement
  • mnky99
  • Sep 5, 2025
  • 1996 - 2004 SN95 Mustang -General/Talk-
Replies
1
Views
449
1996 - 2004 SN95 Mustang -General/Talk- Sep 5, 2025
mnky99
M
T
Intermittent A/C Problem - cold at idle, warm during driving
  • thisxstyle
  • Jun 15, 2021
  • SN95 4.6L Mustang Tech
Replies
15
Views
2K
SN95 4.6L Mustang Tech Mar 29, 2026
nickyb
Share:
Bluesky Email Share Link
  • Mustang Forums
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • Fox 5.0 Mustang Tech
Menu
Log in

Register

  • Forums
  • What's new
  • Media
  • Resources
  • Contact
  • Sponsor
X

Privacy & Transparency

We use cookies and similar technologies for the following purposes:

  • Personalized ads and content
  • Content measurement and audience insights

Do you accept cookies and these technologies?

X

Privacy & Transparency

We use cookies and similar technologies for the following purposes:

  • Personalized ads and content
  • Content measurement and audience insights

Do you accept cookies and these technologies?