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

a/c questions

  • Thread starter Thread starter 93stang burden
  • Start date Start date Jul 26, 2010

93stang burden

Member
Dec 2, 2008
82
0
6
Fort Bragg, NC
Jul 26, 2010
#1
  • Jul 26, 2010
  • #1
I finally decided to put some a/c back in my system that worked last yr. well i put a new motor in this spring and had to realease it all. well now i put 3 cans about 30 oz of 134a in the car and a 3 oz can of oil on the low side right on top of th compresser. well after about 3 or 4 minutes the stupid thing kinda does a blow off valve and lets the pressure off and then continues. Did i put in too much or what?? any input would be aprreciated.
 

jrichker

StangNet's favorite TOOL
In Remembrance. Thank you for your contributions
Mar 10, 2000
27,512
2,811
234
Dublin GA
Jul 26, 2010
#2
  • Jul 26, 2010
  • #2
Did you vacuum the system down good before adding the refrigerant? You need to pull a minimum of 28" vacuum for 30 minutes before adding refrigerant.
 

93stang burden

Member
Dec 2, 2008
82
0
6
Fort Bragg, NC
Jul 26, 2010
#3
  • Jul 26, 2010
  • #3
yep pulled a good vaccum with my pump. but right beside the spot where you fill it on the low side on top of the compressor there is a like blow off valve and its like once it builds up pressure it jsut does a short discharge then another. is there any way to test the switch on the canister??
 

jrichker

StangNet's favorite TOOL
In Remembrance. Thank you for your contributions
Mar 10, 2000
27,512
2,811
234
Dublin GA
Jul 26, 2010
#4
  • Jul 26, 2010
  • #4
The switch on the canister is the low pressure cut off. It is supposed to turn the compressor off when there isn't enough refrigerant to properly circulate the oil.

R134 Refrigerant charge is 26-28 Oz plus 6-8 Oz of PAG 100 oil.
 

93stang burden

Member
Dec 2, 2008
82
0
6
Fort Bragg, NC
Jul 29, 2010
#5
  • Jul 29, 2010
  • #5
ok i put that much stuff in but why would do this crazy blow thing??
 

liljoe07

5 Year Member
Feb 18, 2009
1,622
363
124
Cartersville,Ga
Jul 29, 2010
#6
  • Jul 29, 2010
  • #6
Its possible you have a blockage in the orfice tube, causes the real high pressure on the high side, and low suction pressure. Not even sure if auto ac systems are supposed to go into internal relief( or external in your case).
 
9

93GtMustang50

New Member
Jul 23, 2009
63
0
0
Orlando
Jul 30, 2010
#7
  • Jul 30, 2010
  • #7
did you convert your system to r134a? Maybe thats the problem. Adding r134a to a system designed for r12 will cause all sorts of issues.
 
L

Lawbreaker5.0

Member
Feb 20, 2009
543
2
18
Texas
Jul 30, 2010
#8
  • Jul 30, 2010
  • #8
Three cans is too much. And that valve is a release valve. When you have too much pressure on the high side it will blow out of it. I just did mine two days ago and only needed 2 cans. 14oz cans x 2= 28oz.
 
You must log in or register to reply here.

Similar threads

6
Hey all,I’m putting together a 302 for my 1968 Mustang and wanted to post the combo + some questions to make sure I’m not missing crucial
  • 68_Disgustang
  • Feb 22, 2026
  • 1965 - 1973 Classic Mustangs -General/Talk-
Replies
3
Views
670
1965 - 1973 Classic Mustangs -General/Talk- Feb 28, 2026
Noobz347
M
2001 v6 heater hose quick connect question
  • mnky99
  • Sep 24, 2025
  • SN95 V6 Mustang Tech
Replies
8
Views
462
SN95 V6 Mustang Tech Sep 26, 2025
mnky99
M
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
424
1996 - 2004 SN95 Mustang -General/Talk- Sep 5, 2025
mnky99
M
0
V6 to V8 Swap info
  • 02_2v_Curtis
  • Jan 11, 2026
  • 1996 - 2004 SN95 Mustang -General/Talk-
Replies
0
Views
571
1996 - 2004 SN95 Mustang -General/Talk- Jan 11, 2026
02_2v_Curtis
0
D
Brakes 1966 Mustang convertible 289, Auto - Disc brake conversion issues
  • DRGunn427
  • Feb 26, 2025
  • Classic Mustang Specific Tech
Replies
1
Views
529
Classic Mustang Specific Tech Mar 13, 2025
dmzenge
D
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?