AC Compressor questions, please help! -
LinkBack Thread Tools
post #1 of 3 Old 05-22-2020, 10:13 AM Thread Starter
Registered User
Join Date: May 2020
Posts: 1
AC Compressor questions, please help!

I have installed a new ac system in my 2003 Jeep Liberty 3.7

New accumulator, new condenser, new compressor, all with correct measured amounts of PAG46, and also a new liquid line with orifice tube, and all new gaskets and o-rings on every connection.

Pulled a vacuum and checked for leaking psi, then pulled a vacuum before introducing R134a.

I put about 3 oz of pag46 into the compressor and I hand cranked it about 30 times before I added r134 or plugged in power...

What I am getting here is the same issue I started with... The compressor kicks on and off for 5 seconds at a time, over and over...

The pressure on low side goes from 40-45, compressor kicks on, takes it down to 20-25, then turns off... over and over...

Before all the part swapping, the high side was just matching the low side, but now it seems to go up to 75+ psi when compressor is on...

Anyone know if this could be the high pressure switch or something? Or a problem with the evaporator? (The only major component I didn't replace) Keep in mind the 2003 liberty doesn't have an expansion valve in the evaporator)

Last edited by CWBenjamin; 05-22-2020 at 12:10 PM.
CWBenjamin is offline  
Sponsored Links
post #2 of 3 Old Yesterday, 01:09 PM
Registered User
RussB81's Avatar
2004 KJ Liberty 
Join Date: Jul 2019
Location: Moses Lake
Posts: 147
You don't want the high and low side the same. if it is 80 degrees outside you want around 40psi low and 250psi high. The high pressure switch shouldn't kick off the compressor until 400+ psi. Under 20psi the low pressure switch kicks the compressor off. Have you changed the pressure transducer? It is the part that talks to the PCM. You need a DRB-3 tool to read the transducer. Before you go that route though....

How much R134a did you put in? It might need more. Pull the plug on the low pressure switch and jumper wire the contacts. This forces the compressor to stay on. Add R134a to the low side until it reads 30+ psi. This is how the factory manual tells you to do it. This is how I do it. Also, never ever use the leak stop type R134a. Use the little regular cans without the flashy graphics and marketing claims. R134a is a standardized formulation and that stop leak goop clogs the system and makes things worse.

'04 KJ
'91 XJ, government fleet model with 0 options, 2 wheel drive, 4 cylinders, and 5 speeds
RussB81 is offline  
post #3 of 3 Old Yesterday, 02:25 PM
Web Wheeler
jtec's Avatar
2014 JK Wrangler 
Join Date: Oct 2017
Posts: 8,003
Something is wrong of the high pressure gauge only goes to 75psi.
do you have both high and low pressure gauges?

When I see the price of OEM I think aftermarket.
When I see the quality of aftermarket I think OEM.
jtec is offline  

Quick Reply

Register Now

In order to be able to post messages on the forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.

Email Address:


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On

For the best viewing experience please update your browser to Google Chrome