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88 Jeep Cherokee: O-Ring Count for R134a Conversion?

RVC1 on Wed July 14, 2010 2:41 PM User is offline

Year: 1988
Make: Jeep (i.e., AMC?)
Model: Cherokee Limited
Engine Size: 4.0L
Refrigerant Type: R12 (Assuming)
Ambient Temp: 91
Pressure Low: N/A
Pressure High: N/A
Country of Origin: United States

I found the AC system on my 1988 Cherokee not cooling recently. I have determined that at least the evaporator core is bad. Other system components may also need to be replaced. However, all that remains is conveniently located underhood and I have spare known good parts.

I need the replace the o-rings for R134a. So far, I have located a total of six o-rings:

(2) expansion valve/evaporator core interface,
(1) low pressure valve/line to evaporator interface,
(1) low pressure valve/compressor interface,
(1) high pressure valve/condenser line interface,
(1) high pressure valve/compressor interface.

Is my count total correct? If not please advise as to additional locations.

I can only purchase AC o-rings individually at local auto parts stores so I must be certain I identify all of them in the system in order to convert to R134a...the first time.



Edited: Wed July 14, 2010 at 2:42 PM by RVC1

HECAT on Wed July 14, 2010 3:18 PM User is offline

For a typical TXV system, you will have...

2 at the compressor.
2 at the condenser.
2 at the filter.
2 at the evap (sometimes 4 w/ block TXV).

So my count is 8-10. O-ring kits make this a whole lot easier.


HECAT: You support the Forum when you consider for your a/c parts.


bohica2xo on Wed July 14, 2010 8:51 PM User is offline

An O ring kit is usually the best choice, especially if you have a long drive to the parts store...

There is a 15 buck kit available with all of the O rings in that system - and several spares.

I do see two other seal kits for that vehicle however. Dodge / Chrysler / Jeep used some metal seals, as well as some sealing washers in some places. Your vehicle may need one or more of these seals, depending on what D/C/J was up to that month...

Look HERE for the sealing kits & parts to fit your Cherokee.


"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

RVC1 on Wed July 14, 2010 9:15 PM User is offline

Yes, I did see these o-ring kits. My discussion with the staff at AMA indicated I must separate each connection in the system and examine it for a seal or o-ring in order to determine what quantity of each I will need.


RVC1 on Thu July 15, 2010 4:04 PM User is offline

So now I have read the Hecat flushing procedure document and some posts on this subject. It appears I would have at most three components that one might want to flush. These are:

1. Evaporator core (aluminum one; new from AMA/,
2. Condenser,
3. Low pressure line.

My high pressure line features a metal can that may be a filter or a muffler so I am not to flush this line, the drier, the expansion valve or the compressor with flush solvent.

I have two serpentine condensers; one that came with a parts vehicle purchase; it's connections are open to ambient conditions. The second should be good as I had the AC system of my 89 Cherokee repaired 2-3 years ago and it required a new condenser, drier and compressor valves. I am fairly certain I converted the 1989 Cherokee to R134a so this is consistent with the new drier for the system. The presence of two serpentine condensers makes is difficult to reach for a parallel flow condenser to return this system to operation.

My evaporator core had several small pinholes in one of the tubes (copper?). I did not observe any brown oil on its exterior surfaces when I examined it but I did observe some brown oil escape when I loosened the expansion valve/line connections.

I have not had time to disassemble the sytem completely yet.


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