r12 to r134a with a Parallel Flow Condenser

I’ve never had a Cherokee with working AC I usually buy it broken then it never really gets hot enough to really care. This time I’ve decided to replace all the missing parts so I can be cool for that one week a year we get in Washington.

My old 89 lost some things when I replaced the engine the condenser broke then I threw out the receiver drier and the muffler hose. Here is the list of new parts.

Parallel Flow condenser 10.5”x27”
Receiver/Drier
Cutoff switch
Muffler Hose
90 Degree Conversion Fittings
3 12oz cans of r134a
Can Tap
2x8oz PAG 100 compressor oil
Hecat Safe Flush
O-ring kit
Nylog O-ring lube
Conversion hoses for my existing gauges

Most of the parts are from ackits.com the rest are from various places.

I started by pulling the compressor, battery, and battery tray. Then I did an oil flush of the compressor. The fittings were removed cleaned up and installed new o-rings and conversion fittings. The compressor was turned upside down in a pan and turned over with a ratchet about 15 times to drain out the old oil. I turned it back up and added 4oz of the new pag 100 in the suction side while turning the compressor. Drained it again then repeated the whole process. After it was flushed I added 7oz of new pag 100 oil reassembled and put it back in the vehicle. The other ounce of oil was later put in the Receiver/Drier

After installing the compressor I removed the grill and the top plate that holds the radiator in place and installed the condenser. Last week I did a trial fit and made some brackets. The ac lines didn’t quite match up two inches were removed from the larger hose and some new bends had to be made.

The new muffler hose was also too long. About 3 inches had to be removed. More cutting and welding.

Flushing lines is a big mess I used a sprayer bottle filled with Hecat Safe Flush to get the fluid in. Then used dry filtered air to blow it out and a paper towel on the other end to catch the fluid. I did this three times in different directions and the last time kept blowing until it seemed like it was all out and dry. Things you cannot flush this way hoses with mufflers, condensers, compressors, receiver driers, expansion valves or orifice tubes they need to be replaced or cleaned in some other way. All the hoses are installed with new r134a o-rings coated with nylog and the vehicle is put back together.

Next is the vacuum and charge. The gauges are attached with high and low side valves open and the compressor valves turned in half way. A vacuum is pulled for one hour after 15min you can turn the pump off to see if it holds but this will only tell you if there is a major leak. The gauge valves are closed and the vacuum pump is removed. A can of r134a is attached and the gauges are opened. To keep the pressure up the r134a it can be put in some warm water. When it’s empty close the gauges install another can. Start the engine put the AC on max and slowly open the low side gauge the high side should never be opened. When you get to the third can watch the pressure and the center vent temperature and get it in the range on the chart. Once it’s in the proper range keep adding a little bit to see if the temperature drops any more. When you hit your lowest temperature and it seems to level off close the gauges. Back off the compressor valves so the service ports are closed remove the gauges and install all the caps. You now have a charged ac system.

When I was done I had a little bit left in the last can. When converting a system you will use about 90% compared to r12. Final low temp 42°F on max and seems to keep about 45°F driving around. Low side 16psi high side 187psi.

I’ve always had a fascination with refrigerant systems and I even got a little deep into it building cooling systems for computers. I’m not an automotive AC mechanic so my procedure may not be 100% correct. This worked well for me and others may have different opinions on how to do it.

Impressive post! Most impressive.

Not sure how you got so much R-134a into the system. The books say to use 80%, or 85% of the R-12 level, IIRC, but your method of going for low temp as the best fill level is what I do too. I used a 1997 OEM , parallel flow condenser on my 87 last week. All I could get into the system was about 17 oz of R-134a before it was up and cooling at 45 F on a 90 F day. All I can figure is my condenser (97 OEM parallel flow) holds less, and perhaps my high side hoses hold less liquid than yours. But all I replaced this time was the condenser, and it was much smaller in volume capacity than my old serpentene, OEM condenser. I upgraded from a working condenser to get the compressor pressure down from 330, down to 215 psi, and to get my cooling improved inside the jeep. The P-flow condenser made a HUGE difference on mine. Also the 97 OEM parallel flow condenser is an exact fit, replacement for the 87 and up, unlike the ACkits universal condensers.

Not sure how you ended up with a muffler? Mine (87) never had one, that I recall. My 89 may have one?

I see you went with the new QC fittings. Did ACkits build the hose set for you? I had mine made locally.

I will say this, the R-134a cools as good as the OEM R-12 did with the parallel flow condenser upgrade.

Note for others reading this, the parallel flow condenser is about 40% more efficient and about twice the price of the serpentine condenser. IT is well worth the extra bucks.

I was reading your post last week the OEM route seems like a good idea. I didn't know anything about the newer style at the time so I went with the universal its well built and feels strong.

I think the r12 capacity is 32oz but then you change the condenser and modify the lines who knows what it is any more. It looks like we both did something right since the results are almost identical.

The hoses are original and the muffler came from rockauto. I've owned 2 89's and both had the muffler I should of had one made without the muffler who needs it anyway.

There always seems to be some confusion when it comes to ac I hope this clears it up for some.

The guys on the ackits.com forum are the ones that suggested I go parallel flow too. I looked at theirs but did not see an exact fit, just universals, so I pondered and thought, hmm, I wonder if Jeep made the upgrade P-flow after moving to R-134a, and bingo I got lucky at 1997 in my searches. Seems it was a transition year, as they had both condensers that year, or at least the after market people think so, and offer both for 1997. I think 1997 is when the XJ went to the QC fittings too, as the aftermarket 1997 P-flow has the Qcs, and the serpentene has the threaded fittings, but not sure on that part, as I have seen a 1995 ZJ with the QCs.

By the way, that is way too clean under the hood to be a real 89 jeep!

LOL.

AC started blowing a little warm and I found out the high side compressor valve wasn't sealing all the way. I always have spare parts sitting around so I pulled one off another compressor. It cleaned up great and seems to be working.

The AC is going to cost a lot more than I thought.

Who can guess what this is?

Front seal leak on the compressor.

I found a factory rebuilt old stock compressor on Ebay for $35, buy it now auction, plus $12 freight, with no clutch 4 weeks ago, and put it on the 89. The clutch swap was lot of fun, I went and spent another $18 for a new clutch bearing. Had to pull and press the bearing, Get the front nut and 2 snap rings off, and pull the clutch. Lucky I had a press, a good large snap ring removal tool set, and a complete puller set, but I save a ton of $$$s!

Wow! that has to be the cleanest engine compartment I've ever seen on a Jeep... great writeup! I'll hopefully be grabbing most of the A/C components from another '96 at the junkyard soon, as mine are hopelessly rusted and my AC will work for a few hours if I refill it with refrigerant.

I was going for that new car feel it's great not getting dirty anymore.

I'm still trying to decide what to do:
1. Free, use extra compressor I already have probably will not last long.

2. Ecomike's idea cheap should last a while

3. Very expensive, find a new r134a compressor that will fit.


Sorry about the missing pictures ImageShack keeps losing my stuff. I need to start hosting things myself.

I am pretty sure there were (are) several rebuilt compressors with clutches for about $90 to $130 on Ebay. I just could not pass up the $75 savings to reuse the clutch.
I have bought several (3) rebuilt compressors the last 3 years on Ebay, and been happy with the results. And they are always about 1/3 of what the local guys want.

Wouldn't Ester Oil have been a bit better since it won't form sludge in systems that previously contained R12?

LOUD02Special said:

Wouldn't Ester Oil have been a bit better since it won't form sludge in systems that previously contained R12?

Click to expand...

Pray tell us more, Sludge?

Most of the retailers are stocking just PAG oil now, IIRC.

Ecomike said:

Pray tell us more, Sludge?

Most of the retailers are stocking just PAG oil now, IIRC.

Click to expand...

PAG Oil, when used in applications of R12 systems converted to R134a, can form sludge, especially in the compressor and evap core. Ester Oil is mixable with any oil and will not form aforementioned sludge. I just did a re-build of the whole A/C system in my 2002 300M Special and did a LOT of reading about the differences between PAG and Ester. Advance Auto Parts stocks both PAG in its several different forms and Ester Oil.

LOUD02Special said:

PAG Oil, when used in applications of R12 systems converted to R134a, can form sludge, especially in the compressor and evap core. Ester Oil is mixable with any oil and will not form aforementioned sludge. I just did a re-build of the whole A/C system in my 2002 300M Special and did a LOT of reading about the differences between PAG and Ester. Advance Auto Parts stocks both PAG in its several different forms and Ester Oil.

Click to expand...

I would love to see some references?

I'll try to find the sites I was reading about PAG oil. It was about 2 months ago when I was doing the research about what kind of oil I should use when I installed the new EVAP and Receiver/Drier.

EDIT: Found one that I definitely read about.

http://www.autofrost.com/hotshot/index.html

I don't think sludge was my problem. The compressor is 20 years old and probably has not been used for 10 I was taking a chance using it in the first place.

LOUD02Special said:

I'll try to find the sites I was reading about PAG oil. It was about 2 months ago when I was doing the research about what kind of oil I should use when I installed the new EVAP and Receiver/Drier.

EDIT: Found one that I definitely read about.

http://www.autofrost.com/hotshot/index.html

Click to expand...

Thanks, keep looking, this is most interesting!

I am going to take one pot shot at that one. Change in color is a poor way to judge loos of important lubricant properties. Look at diesel oil just after 10 minutes of run time, it turns black as can be. But to make my point, color tells you nothing, sludge can be filtered and weighed, acid formation, or depletion of acid neutralizing ability can be measured and quantified. Loss of lubrication ability, loss of viscosity, can all be measured. I did not see any of that in that link, which makes me question its value.

THe rest of the discussion about different blends was quite interesting too.

Anyway, I am not saying there is not a problem, just asking for better evidence. :cheers:

One thing that is often overlooked is the need to change the desiccant. The old R-12 desiccants, I am told, decompose and form sludge on exposure to the R-134a and its oils.

Here is something completely not OEM. I made this acrylic fan shroud to help with the AC cooling.

Nice!

I think this is what I need to do. I finally am needing to change my condenser due to a leak at the top fiiting and of course on an 89xj the fitting won't turn....now I bent the condenser and it is still stuck.

So I bought at O'rielly the Ready-Aire 637362 condenser (it is Serpentine) for my year at $130 that comes with the extension lines. The extension lines are different that mine and look to be very tight. I gues there is a type 1 and a type 2. I could have removed the lines, but I don't want to risk damange. So I Returned the part. Next I ordered a Silla C7361for $125 the SILLA is terrible and is the old tube and fin design line on my old 70's Camaro. I requested an RMA for the Silla. Lastly the Type 1 Factory Air condeser for my XJ is 250 at O'rielly since I have the OEM #56002956.

So now I am off to get a parallel condenser. THANKs for diving in and letting us know your success. My advice is to NOT buy Silla not matter what the case even R-12.

Also I found R134 fittings at Jeep Air in Florida that replace the ones on the compressor and both were $27 or 15 each. I hate those R134 conversion Fittings had them leak before.