97 TJ AC Rebuild

[Metalforger71]

Hi All, I'm Matt and this is my first post. My TJ has factory air, but was not working when I got it. And from the looks of the system it has not ran for awhile. The interior control box was jacked (bought a used one) and the compressor was frozen. The engine was running with a non-ac serpentine belt. I'm sure I will find more issues as this project progresses so I will give a history of what I know and where im at. (I do have a question lol)

I purchased a new compressor kit with a new accumulator, suction line, oil, etc. Before I started taking the old system out I hooked up my guages to check for refrigerant. There was none. For kicks I pulled a vacuum down to 29 inHG and it held fine. I also pressurized the system to about 60psi and that also held. I was really just making sure the condenser was not punctured or anything.

The old compressor is out and it has zero oil in it. The old accumulator also has no oil in it. This is no doubt why the compressor froze. I understand there could be oil in the condenser, but this seems unlikely now and I know that the total system takes 8oz of oil. Soooooo.....

How much oil should I be adding to the system? 8oz? Are there any other procedures I should do before putting the new components in in regards to the oil capacity?

Thanks, Matt

 

[TJ4Jim]

Several things I would do regardless of condition as it can be expensive opening and closing the system multiple times.

Replace the liquid line as it houses the metering device with a screen filter, it is inexpensive and can foul up the works.

Get an O ring kit and replace everything even if it held pressure, be sure to use the correct O ring lubricant.

Any decent Auto parts store should have A/C flush kits, get some and do the evap and condenser coils.

Since the system has been open give the vacuum pump some extra time to get it good and dry.

It can be a pain to determine oil fill quantities and location. The FSM gives a decent guide so if you do not have one check out the resource section.

 

[TrueTexas]

Download the service manual. Just do a search on here to find it

I would give the oil type but the manual gives both ND8 and SP-20 in different locations. Not 100% sure which to use

 

[CharlesHS]

IF you are unsure whether there is oil settled in the condenser while changing out the O rings apply air pressure to one of the condenser lines to push any oil out so you can be sure of how much oil you are adding to the compressor.
I am sure you know, but only use PAG oil for the R134a system.

 

[Rubicon John]

First off, vacuum the ever loving sheit out of that system with an A/C machine, the longer the better.

Then put a couple oz of oil in the new compressor and prime it by hand. Install all your new components.

Put a couple more oz oil in when you charge it. See how it runs while monitoring the pressures. I’d be willing to bet it will be good at that point.

Ive worked on hundreds of A/C systems and have never run into an oiling issue. If you don’t have a machine this might be a bit more difficult.

 

[Metalforger71]

10-4 on replacing the liquid line and the kit I bought has all the 0-rings and oil. I have the FSM. I was asking about capacity with the possibility of having oil in the system. Flushing and purging sounds like a great idea and I have a very powerful vacuum pump. Thanks for the prompt replies!

 

[Metalforger71]

Actually a new liquid line came with my kit. I called it a suction line

 

[Metalforger71]

Well I figured I would ride this project out to the end here on the forum lol. I ended up replacing the compressor, liquid line, accumulator, o-rings, and suction/discharge lines. All said around $250 from Rockauto shipped. Leaving the condenser and evaporator alone. Hooked it up and pulled a vacuum and it leaks. Pressurized and leaks as well. And not a very small one. I am positive I didnt have my gauges open when I initially did this test and thought it didnt leak. I was probably just pulling vacuum on my gauges. Doh! Anyway, found a small leak at the condenser where it bolts on and fixed that. Still leaks. Pulled out my radiator to get to the condenser (planned on a coolant flush anyway) and checked for leaks, none. Pressurized and put my ear to the HVAC box and I can hear the evaporator hissing. So I ordered a new evaporator and heater core (might as well) from Rockauto and started removing my dash. But of course my aftermarket roll cage is in the way of getting my dash out so that came out along with my seats lol. Sandblasting and painting my cage was on my list anyway. Soooo.. as this project keeps getting bigger and bigger, hopefully next weekend I will actually circle back to the beginning

 

[Vidar]

Well I figured I would ride this project out to the end here on the forum lol. I ended up replacing the compressor, liquid line, accumulator, o-rings, and suction/discharge lines. All said around $250 from Rockauto shipped. Leaving the condenser and evaporator alone. Hooked it up and pulled a vacuum and it leaks. Pressurized and leaks as well. And not a very small one. I am positive I didnt have my gauges open when I initially did this test and thought it didnt leak. I was probably just pulling vacuum on my gauges. Doh! Anyway, found a small leak at the condenser where it bolts on and fixed that. Still leaks. Pulled out my radiator to get to the condenser (planned on a coolant flush anyway) and checked for leaks, none. Pressurized and put my ear to the HVAC box and I can hear the evaporator hissing. So I ordered a new evaporator and heater core (might as well) from Rockauto and started removing my dash. But of course my aftermarket roll cage is in the way of getting my dash out so that came out along with my seats lol. Sandblasting and painting my cage was on my list anyway. Soooo.. as this project keeps getting bigger and bigger, hopefully next weekend I will actually circle back to the beginning

Lol. My engine blew so I ended up rebuilding it. While I was at it, I pulled the dash apart so I could replace the heater core. That led to replacing the whole AC system (except the compressor since that’s running well). Since I pulled the dash I decided to repaint the whole interior. Clear coat was gone from the hood so, why not, repaint the whole car. Oh, and let’s put a body and motor lift on it, cause why not. It just never ends, does it?

Good luck on your ac overhaul.

 

[CharlieCharlieCharlie]

Any chance you could post a picture for the layout on the AC system.
I have a 97 4.0, no AC.

Trying to piece one together, but not sure what side the dryer sits on.
Some on the drivers side from what I have scalped from photos, but others on the passenger side in the engine compartment?

 

[Vidar]

Any chance you could post a picture for the layout on the AC system.
I have a 97 4.0, no AC.

Trying to piece one together, but not sure what side the dryer sits on.
Some on the drivers side from what I have scalped from photos, but others on the passenger side in the engine compartment?

On your 97 the dryer connects to the evaporator line coming through the firewall from the dash, next to the heater core lines, on the passenger side. The bracket connects to the two hvac box posts that come through the firewall. I’ll get some pics for you when I head out to my garage later this morning.

 

[Vidar]

Any chance you could post a picture for the layout on the AC system.
I have a 97 4.0, no AC.

Trying to piece one together, but not sure what side the dryer sits on.
Some on the drivers side from what I have scalped from photos, but others on the passenger side in the engine compartment?

Here you go. I tried to show where the bracket attaches at the firewall and how the two brackets connect on the side.

 

[CharlieCharlieCharlie]

Awesome, thanks Vidar!

Here you go. I tried to show where the bracket attaches at the firewall and how the two brackets connect on the side.

View attachment 168609

View attachment 168610

View attachment 168611

 

[steveveweve]

IF you are unsure whether there is oil settled in the condenser while changing out the O rings apply air pressure to one of the condenser lines to push any oil out so you can be sure of how much oil you are adding to the compressor.
I am sure you know, but only use PAG oil for the R134a system.

 

[Midtenn]

How do you test if the compressor is locked up?

 

[Metalforger71]

Well my thread took off in a few directions, but I thought I would close it up. I ended up replacing the entire AC system minus the Condenser. I did replace the O rings in it though. It looked fine and didn't leak. My climate control assembly in the dash could not have been broke in more places and I had to get one off Ebay because they were only a two year part. (sliders) Anyway, I added oil based on the service manual, pulled a vacuum for a long time, and charged her up. Everything has been working great. All in all I put a little less than $500 in it. It was a ton of work, but would have cost a small fortune at a shop. While my jeep was gutted I repainted it and built a new cage. I wanted a fastback style cage anyway. I still need to build a new rear bumper and tire carrier but here are some pics.

 

[SSTJ]

Hey, I know this is old, but do you mind sharing which kit you bought?