2.5Litre AC

[eaglescout526]

I swear, each day passes and I get more stressed over this damn set up. (Note to self, don't be a HVAC tech) As I'm gathering parts and acquiring as much info I can, the 2.5L seems to be buried in a sea of 4.0's, I have a few questions. Currently everything is in good shape, hoses are filthy on the outside but clean internally as well as evap. Parts that will be replaced are the condenser, expansion valve, dryer, compressor and O-rings. Currently have new expansion valve and condenser.

Planning on buying Jeep air's retro fit kit, any opinions on this?

Any former dealership or current dealership guys know of an official MoPar R12-R134a conversion kits with manuals to have existed back then?

What the heck are these fittings?:

This looks like a conversion as these don't match any R12 fittings from the AMC era

 

Once I have this puzzle all together, how many pounds of R134 go into the system(as far as how much the 2.5L system holds)? Planning on having my work assist me with the charging but most of the techs have told me to have conversion info to provide to them before they charge it.(or at least a label showing it has been converted, more so added to the truck.)

Ultimately it seems like I need to have all the fittings tight and leak free with replaced O-rings once it is all installed. I have zero experience with AC, so finding leaks and using manifolds and reading them is like reading hieroglyphs to me.

 

All these parts came from an 87 MJ or XJ Renix jeep.

[zomeizter]

I converted mine a few years ago by doing the following:

New compressor, expansion valve, receiver/drier, replaced all o-rings to the 134a type (green/purple), completely flushed condenser, evaporator and all hoses. A quick google search can reveal you the specifications for oil (PAG) and refrigerant charge, IIRC you have to use 15% less 134a refrigerant than the R12 quantity specified. For the fittings, you can find the kit at any auto parts store, this will allow you to use the 134a hose connections for your gauges or A/C service machine. My conversion went very well, it gets ice cold even in the hot summer days here in the south. My 2.8L setup was equipped with a mechanical fan which was replaced with an electric fan setup which helps a bunch with A/C performance when stuck in traffic.

[Jeep Driver]

1 hour ago, zomeizter said:

I converted mine a few years ago by doing the following:

New compressor, expansion valve, receiver/drier, replaced all o-rings to the 134a type (green/purple), completely flushed condenser, evaporator and all hoses. A quick google search can reveal you the specifications for oil (PAG) and refrigerant charge, IIRC you have to use 15% less 134a refrigerant than the R12 quantity specified. For the fittings, you can find the kit at any auto parts store, this will allow you to use the 134a hose connections for your gauges or A/C service machine. My conversion went very well, it gets ice cold even in the hot summer days here in the south. My 2.8L setup was equipped with a mechanical fan which was replaced with an electric fan setup which helps a bunch with A/C performance when stuck in traffic.

Yep, that's exactly what I did but sounds like you had better luck, mine didn't last long. 

[Jeep Driver]

7 hours ago, eaglescout526 said:

I swear, each day passes and I get more stressed over this damn set up. (Note to self, don't be a HVAC tech) As I'm gathering parts and acquiring as much info I can, the 2.5L seems to be buried in a sea of 4.0's, I have a few questions. Currently everything is in good shape, hoses are filthy on the outside but clean internally as well as evap. Parts that will be replaced are the condenser, expansion valve, dryer, compressor and O-rings. Currently have new expansion valve and condenser.

Planning on buying Jeep air's retro fit kit, any opinions on this?

Any former dealership or current dealership guys know of an official MoPar R12-R134a conversion kits with manuals to have existed back then?

What the heck are these fittings?:

This looks like a conversion as these don't match any R12 fittings from the AMC era

 

Once I have this puzzle all together, how many pounds of R134 go into the system(as far as how much the 2.5L system holds)? Planning on having my work assist me with the charging but most of the techs have told me to have conversion info to provide to them before they charge it.(or at least a label showing it has been converted, more so added to the truck.)

Ultimately it seems like I need to have all the fittings tight and leak free with replaced O-rings once it is all installed. I have zero experience with AC, so finding leaks and using manifolds and reading them is like reading hieroglyphs to me.

 

All these parts came from an 87 MJ or XJ Renix jeep.

The brackets were all you needed to find. 

 

Everything else should have come from JeepAir............meanwhile, I'm afraid you are wasting your time and energy. 

[Minuit]

The factory charge is 38oz R-12 and 6oz of mineral oil according to the 1990 FSM. R-134a charge weight will be 84% of the original, so 31.92oz of R-134a and 6oz of PAG oil is what you'll want. SD-709 compressors spec PAG 100, but I'm not sure about the 508. Distribute the 6oz of oil however you like. Half in the compressor and half in the condenser, all of it in the compressor (just turn the compressor over about 10 times immediately prior to charging), as long as you get 6 oz of oil into the system. It will be circulated by the refrigerant as soon as the system is turned on for the first time.

 

Apply some PAG oil to all o-rings before installing them. Make sure the o-ring seats before you tighten the fitting. It's hard to describe, but you'll know the feeling once you do it a couple of times. The o-ring should not be extremely difficult to seat, but there should be some resistance. If there is any dirt on any o-ring, it is JUNK and do not attempt to use it. Make sure all o-ring surfaces are clean. If you drop an o-ring on the floor, it is JUNK and do not attempt to use it. Do not reuse o-rings. Work with clean hands and tools at all times. Do not allow any dirt to be introduced into the system. Buy a couple of o-ring sets for the vehicle and have an o-ring assortment kit on hand.

 

Do the service ports have schrader valves in them?

 

The receiver drier should be the VERY last thing you install. Don't even take the plugs off of it until it is mounted in the vehicle and you have the lines ready to connect to it. The system should be sealed as quickly as possible after the plugs are pulled on the drier. It should be replaced any time the system is opened.

 

A vacuum test is not an acceptable method of leak-checking. If your dealership has access to real leak checking equipment such as pressurized dry nitrogen (any proper A/C shop should), use that instead. Failing that, the system should hold a 30inHg vacuum for at least one hour with NO loss of vacuum. If the gauge deflects at all, you have a leak and you will be doing this again, so get it right on the first try.

 

Is your condenser a "parallel flow" design? Those are strongly preferred for R-134a. Using an original-style serpentine condenser with R-134a is likely to result in sub-par performance at idle.

 

That's most of it. I'm sure I'm forgetting something.

[eaglescout526]

Awesome! I appreciate the info guys. 

Definitely get the kit from Jeepair and not worry about these weird fittings on the compressor.

Condenser is NOS so chances are Chrysler made it for R134a specs.

I'll keep this topic open on my computer until I complete this project.

1 hour ago, Minuit said:

Do the service ports have schrader valves in them?

Yes the fittings have Schrader valves which is why I was confused.

 

Now another question, should I take a gamble on the factory evap or buy the one from Jeepair? I only ask because of the crap shoot that the replacements are not built in a factory OEM manner, meaning they are missing the thermostat hole.

 

[Minuit]

The factory condenser until 1997 was a serpentine design. If the cooling does not satisfy you, you may want to consider an aftermarket parallel-flow condenser.

 

The evaporator issue was one I wrangled with too. I ended up seeking out a NOS evaporator. That thermostat is critical to the operation of the system. In some situations, that thermostat is what controls the compressor cycling. The Renix evaporator is different, so good luck finding one. I'd be tempted to keep the original unless an issue crops up with it. That's not my usual MO when working on A/C, but the evap replacement is a BIG job and not one I'd do if the evaporator wasn't bad. ESPECIALLY if the only available replacement was an inferior part.

 

Get a set of retrofit adapters that have a pushrod for the schrader valve.

[eaglescout526]

Will do. It looks like the Jeepair kit has a compressor with the proper fittings for R134a so I won't need much from this compressor I have now. I guess I could go to AMC salvage and literally take what ever evap is still sitting in their Jeeps as spares. And there is a lot of them still sitting with the air boxes intact.

[Big Dan]

What "kit" are you getting from jeepair?  I thought that they only offered CJ/YJ/TJ kits.  Other vehicles had to have components sourced in a piecemeal fashion.

 

Is that incorrect?

[eaglescout526]

https://jeepair.com/compressor-kits/1987-1990-cherokee-compressor-kit-603.html

 

XJ and MJ kit they offer. 

[Minuit]

Important: that kit mentions that the compressor is fully charged with oil. That means you won't need to add any. You can drain and refill if it makes you feel better (there should be about 6oz in it) but you don't need to add more as long as the compressor has the correct amount.

[eaglescout526]

18 minutes ago, Minuit said:

Important: that kit mentions that the compressor is fully charged with oil. That means you won't need to add any. You can drain and refill if it makes you feel better (there should be about 6oz in it) but you don't need to add more as long as the compressor has the correct amount.

Yup. Been studying that thing like a text book. Damn paycheck. Going from hourly to salary sucks for that little bit

[Minuit]

Now all you've got to do is just get it all done before winter! I'm really bad at that part.

 

Do you even have winter over there?

[eaglescout526]

19 minutes ago, Minuit said:

Now all you've got to do is just get it all done before winter! I'm really bad at that part.

 

Do you even have winter over there?

Goal is to have it all done and assembled by the end of August. Figure it should take me a weekend to tear out the dash and install everything under the hood. Once I get paid again I’ll get the AC kit and appropriate hoses and such. 

 

Winter? 

Best way I can describe our winter is the equivalence to Alaska’s summer.(been to Alaska during the summer. Felt the same as winter here). It “cools” off but we see high 60’s to 70’s during the day.