AC question
#1
Newbie
Thread Starter
Join Date: Jul 2010
Location: Smithton, IL
Posts: 14
Likes: 0
Received 0 Likes
on
0 Posts
Year: 1998
Model: Cherokee
Engine: 4.0
AC question
I have confirmed the operation of the compressor clutch. Tested the system for pressure. Needs freon. Had a code scan, nothing showed. I am questioning if it is just a low system pressure, low freon, or a possible bad relay or interior selector switch.
Thanks
Thanks
#3
Newbie
Join Date: Feb 2010
Location: Iowa
Posts: 26
Likes: 0
Received 0 Likes
on
0 Posts
Year: 2001/1996
Model: Cherokee
You say the system is low on refrigerant. That is the first place you need to start. These systems only hold 1.25 lbs. of R-134A so it doesn't take much of a leak to make them low and non-functional. If you don't have access to the proper gauges, vac pump and leak tester you might be better off taking it to a shop for diagnosis.
If the system is empty vac it down for 15 min, close the valves on the gauges and watch the vacuum on the low side gauge for about 15 min. If it stays steady after the first minute or two it might be normal seepage and just need recharged. If the vacuum drops then you have a leak. You might need to add a partial charge and check with a leak detector. If you don't find any leaks underhood, turn the blower fan on low and use the tester to check the vents. These are known for evaporator coil leaks.
Jim S
If the system is empty vac it down for 15 min, close the valves on the gauges and watch the vacuum on the low side gauge for about 15 min. If it stays steady after the first minute or two it might be normal seepage and just need recharged. If the vacuum drops then you have a leak. You might need to add a partial charge and check with a leak detector. If you don't find any leaks underhood, turn the blower fan on low and use the tester to check the vents. These are known for evaporator coil leaks.
Jim S
#4
Senior Member
Join Date: Oct 2008
Location: Port Orange, FL
Posts: 871
Likes: 0
Received 0 Likes
on
0 Posts
Year: 1993, 1994
Model: Cherokee
Engine: 4.0L HO
You say the system is low on refrigerant. That is the first place you need to start. These systems only hold 1.25 lbs. of R-134A so it doesn't take much of a leak to make them low and non-functional. If you don't have access to the proper gauges, vac pump and leak tester you might be better off taking it to a shop for diagnosis.
If the system is empty vac it down for 15 min, close the valves on the gauges and watch the vacuum on the low side gauge for about 15 min. If it stays steady after the first minute or two it might be normal seepage and just need recharged. If the vacuum drops then you have a leak. You might need to add a partial charge and check with a leak detector. If you don't find any leaks underhood, turn the blower fan on low and use the tester to check the vents. These are known for evaporator coil leaks.
Jim S
If the system is empty vac it down for 15 min, close the valves on the gauges and watch the vacuum on the low side gauge for about 15 min. If it stays steady after the first minute or two it might be normal seepage and just need recharged. If the vacuum drops then you have a leak. You might need to add a partial charge and check with a leak detector. If you don't find any leaks underhood, turn the blower fan on low and use the tester to check the vents. These are known for evaporator coil leaks.
Jim S
Dead on. Even a little loss of coolant will disable the AC, since the AC will detect the pressure as invalid and cut out the compressor in an attempt to save itself, since the coolant is also the lubricant for the compressor.
#5
CF Veteran
Join Date: Nov 2009
Location: The Republic of TEXAS
Posts: 8,172
Likes: 0
Received 14 Likes
on
14 Posts
Year: 1998
Model: Cherokee
Engine: 4.0L HO
Coolant is what's in the engine and radiator, not the a/c. The a/c has freon/refrigerant in it along with oil. The freon/refrigerant does not lubricate the compressor.... oil does.
#6
Senior Member
Join Date: Oct 2008
Location: Port Orange, FL
Posts: 871
Likes: 0
Received 0 Likes
on
0 Posts
Year: 1993, 1994
Model: Cherokee
Engine: 4.0L HO
Ok, refrigerant. My bad, I used the wrong word. And the oil is suspended in the refrigerant, so if you are out of refrigerant, there is no oil. Unless you have a real old school York or similar compressor, of course.
Trending Topics
#8
CF Veteran
Join Date: Nov 2009
Location: The Republic of TEXAS
Posts: 8,172
Likes: 0
Received 14 Likes
on
14 Posts
Year: 1998
Model: Cherokee
Engine: 4.0L HO
Some of those a/c quick fix cans at Walmart have oil in them because it was added when the can was filled with refrigerant. Not all cans of refrigerant have oil added to them. R134a systems are very sensitive to the correct amount of oil and pressure as too much oil greatly reduces cooling efficiency and too little oil spells disaster for a compressor, including a old school York.
Wars have gotten started over using the wrong word(s).
Last edited by djb383; 08-29-2010 at 03:11 PM.
#9
I'm kinda having the same issue. my jeep is blowing warm air when i turn on my a/c. I recently took it to a a/c "specialist" and said i had my low and high Freon pressure too high. After setting them correctly. i still have the same issue. checked my clutch, Radiator fan, condenser fan, and noting seems to be wrong. any suggestions?
Thread
Thread Starter
Forum
Replies
Last Post
Kydude7
Stock Grand Cherokee Tech. All ZJ/WJ/WK Non-modified/stock questions go here!
7
09-20-2015 06:35 AM
codykrr
Modified XJ Cherokee Tech
9
09-18-2015 01:27 PM
mach3lude
Modified XJ Cherokee Tech
17
09-10-2015 02:34 PM
Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)