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  #21  
Old 07-22-2020, 09:57 PM
mantonas mantonas is offline
230 Tornado
 
Join Date: Apr 16, 2017
Location: Knoxville, TN
Posts: 19
If I replaced the compressor with another York unit, how do I add oil? Does it go into the "crankcase" of the compressor itself before it's installed, or do I just get one of those cans and feed it into the system the same way you add refrigerant?
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  #22  
Old 07-24-2020, 05:29 PM
Dave Jeeper Dave Jeeper is offline
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Join Date: Sep 08, 2019
Location: Denver, CO
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In the photo of the compressor that was posted, there is a large hex nut on the side of the compressor, next to the edge of the radiator hose. Normally the compressor would be oriented with that hex nut on the top of the compressor and I believe that is where the dipstick would be put in after removing the nut (compressor in use must have pressure removed before opening and must be evacuated-with a vacuum pump- afterwards before recharging).


An AC system takes a certain amount of oil, some systems take 8 oz, not sure what this one takes. Some of the oil circulates around with the freon. There will be some in the compressor, some in the accumulator/dryer, some in the evaporator. When replacing a part, such as the compressor, drain the oil from the used part and measure how many ounces were in the used part. If the new part (compressor) comes with oil, then drain it, and put new oil back in the compressor equal to the amount of used oil removed from the used part. This will work if oil has not leaked out of the system.



If there are signs of leaked oil around a loose connection, then you may need to add more oil than was in the compressor.



If the valves in the compressor went bad and shattered, then you will have to replace more parts than just the compressor as the broken parts travel upstream with the high pressure freon.


Mineral oil is used in the original configuration with freon 12. There are different weight PAG oils used with R134a if the system has been converted. Best to try to figure out which PAG oil is in the system if converted. There may be info on the compressor or a conversion sticker stating which oil is in the system.


Good luck,
David
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  #23  
Old 07-25-2020, 08:58 AM
mantonas mantonas is offline
230 Tornado
 
Join Date: Apr 16, 2017
Location: Knoxville, TN
Posts: 19
Ok, don't judge me, but I decided that I didn't want to mess with replacing hoses or fooling around with the A/C box inside the car to remove the expansion valve, so I bought a compressor, receiver/dryer, and condensor from Rockauto and I'm going to replace them all and put in R134 plus some amount of oil. Since I'm not removing the expansion valve there's not gonna be a lot of flushing going on. If this doesn't work or works but doesn't last a long time or ends up damaging other components, oh well, but if I get one summer out of it I will be happy. As I said, please don't judge.

The new compressor says it's filled with 14.1 oz. of PAG 100 oil. I will do what was recommended above and measure how much oil was in the old compressor and go from there. I guess I will try to stick with PAG 100 oil because I think the oil is mostly there to lubricate the moving parts of the compressor and it came with PAG 100 so that must be what it needs.

Now I just want to make sure I have all the right parts, and I guess I'm mostly thinking about O-rings or other gaskets. I don't plan to disconnect the hoses from the service valves, so I probably need new O-rings or gaskets (I don't know which) between the service valves and the compressor. What do I need there?

Also, the hose that connects the compressor to the condenser: as I said I don't plan to disconnect that at the service valve, but I do at the condenser because I'm replacing the condenser. That's a big hose; is it a #10? #12? What size O-ring does that take? I picked up a pack of O-rings at Advance yesterday that I think will probably give me what I need for the smaller liquid line hose connections but it didnt look like it included big enough O-rings for the compressor discharge line.

Thanks!
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  #24  
Old 07-25-2020, 09:24 AM
wiley-moeracing wiley-moeracing is offline
350 Buick
 
Join Date: Feb 15, 2010
Location: arizona
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You will still need to remove the expansion valve to flush the system properly. It should not be that hard to get to if it is the under dash system. Most o ring kits should have the correct size in them for your system.
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  #25  
Old 07-26-2020, 10:35 PM
SJTD SJTD is offline
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Join Date: Apr 26, 2012
Location: Lompoc and Sunland, CA
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I agree. Everything I've read says you don't want to mix PAG with the mineral oil used with R12.

But it's your vehicle.
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  #26  
Old 07-29-2020, 08:54 PM
mantonas mantonas is offline
230 Tornado
 
Join Date: Apr 16, 2017
Location: Knoxville, TN
Posts: 19
As far as ease of removing the expansion valve because it's an under dash system: compared to what?!? I love my Grand Wagoneers, and I've got several other AMCs that I also love, but I am a recovering Mopar guy, and they all had the expansion valve in the engine compartment. You can easily remove it and flush the evaporator. God forbid my ever owning a (barf) GM vehicle, but they're even easier: evaporator in the engine compartment!

I guess it's easy compared to other AMC vehicles which also have the expansion valve on the interior side of the firewall but all up inside the dash instead of an underdash system. I think it's extraordinarily daunting to even think about removing the expansion valve just so I can flush the evaporator. If I ever get to the point where I have to do that, then screw it, I'm gonna replace EVERYTHING.

For now, here's my under 300 dollar plan (remember, a previous owner already converted it to R134a)

New York-style compressor, new condenser, new receiver dryer (Rockauto)

4.5 oz of PAG 100 oil in the compressor

Two cans of R134a refrigerant

I found the weird square-cross-section gaskets for the service valves to the compressor at O'Reilly, so I'm not going to disconnect the hoses from the service valves, I'm going to disconnect the service valves from the compressor to replace the compressor.

I have bought multiple O-ring kits but none of them seem to have O-rings big enough for #10 hoses, so I ordered a kit from Jeepair.com. it was supposed to get here yesterday, then it was delayed to today, now it's delayed til tomorrow. Not having those O-rings is the only thing that might derail me doing it this weekend.

Reuse the clutch.

Rent a vacuum pump, get rid of the existing refrigerant, pull a good vacuum, add refrigerant

If that doesnt work I'm going to admit defeat and buy a minivan.
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  #27  
Old 07-29-2020, 10:55 PM
SJTD SJTD is offline
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Join Date: Apr 26, 2012
Location: Lompoc and Sunland, CA
Posts: 1,460
Sounds good. I missed where it was already converted to 134, presumably the system was flushed at that time and filled with PAG oil.
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  #28  
Old 08-12-2020, 08:24 PM
mantonas mantonas is offline
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Join Date: Apr 16, 2017
Location: Knoxville, TN
Posts: 19
Ok, here's what I ended up doing and how it worked. Sorry this post is so long, but there's a question at the end that I need help with.

As I said in my earlier post, I wanted to get the A/C working without having to replace a bunch of hoses. This was primarily to keep it a one-weekend job. So I ordered the cheapest York-style compressor, receiver/drier, condensor, and O-ring kit from RockAuto. I planned to disconnect the service valves from the compressor but not disconnect the hoses from the service valves. Somewhere along the way, I discovered that special square-cross-section O-rings were required between the service valves and the compressor. Here are the part numbers and prices for all the parts I bought:

Compressor: GPD 6511739 $162.79
Receiver/drier: GPD 1411380 $14.87
Condenser: UAC CN3731PFC $60.79
O-ring kit: GPD 1321292 $3.83
Service valve gaskets: Four Seasons 24117 $3.80 (pack of 10)

So I removed the radiator, fan, pulley, belts, etc., disconnected the service valves from the compressor, got the old compressor off (found a huge amount of old mouse poop in a cavity between the compressor and the bracket), and removed the old condenser and receiver/drier. (Note: the old system was indeed holding pressure. Don't ask me how I know.)

I placed the new condenser in and while the mounting brackets fit, I noticed the condenser was much smaller than the original. This worried me, because it's my understanding that a good condensor is a must to convert an R12 system to R134a. So I went back to the Rockauto website and discovered that the only other condenser they list for a Grand Wagoneer was significantly larger. I didn't buy it originally because it was a lot more expensive, but now I decided I needed it, so I ordered it. It was going to take long enough to ship that I was going to have to wait until the next weekend to finish the job. Crap.

Heres the cost of the new condenser:

APDI/PRO 7013731 $99.79

So I expanded the scope of the project. I decided to fix the absolutely terrible hose-clamped splice that a previous owner had put in the hose returning from the evaporator to the compressor. I bit the bullet and bought a hydraulic bubble crimper from Amazon that had fast shipping, and I bought a set of male and female flared connections to install at the break in the hose so i would only have to do one field crimp. At that point I got new compressor suction and discharge hoses fabbed by Royal Brass and Hose here in Knoxville, Tennessee. For the compressor discharge hose leading to the condenser, I had the shop cut off and reuse the factory end at the condenser because it was pretty tight in there and it would be hard to get a hose with a standard end to fit. For the compressor inlet hose, I had it fabbed with the compressor connection crimped on and the other end bare so I could crimp on my other threaded flared connection.

Here is the cost of some more parts:

Hydraulic bubble crimper from Amazon: iGeelee Hydraulic A/C Hose Crimper $138.98

Crimp-on fittings from Rockauto:

#10 female flare: Four Seasons 10410 $4.79

#10 male flare: Four Seasons 10110 $7.93

Hoses: ended up costing about $70 for two hoses after multiple trips. I could have done all my own crimping except for transferring the original hose end onto the new hose, which required brazing.

I also replaced the high and low side R134a charge ports with new ones I bought at Advance Auto Parts (both Factory Air brand) and bought new service valve caps from Rockauto (a Four Seasons part). Part numbers and cost:

59976 Low side 1/4" fitting $5.79
59968 High side 3/16" fitting $6.79

59622 service valve caps $3.75 (pack of 5)

An annoying detail that I spent way too long to address: the original condenser had mounting points for the receiver/drier. The new receiver/drier was set up for this but neither of the condensers had a place for it to attach, so I fabbed a bracket for the receiver/drier.

Oh, and the new condenser was not any bigger than the first one I bought, and was actually a little thinner, but I let my wife choose which one I should use and she liked the more expensive one so I used it. I was pretty over it at this point.She knows nothing about cars, btw.

I drained about 14 oz out of the compressor and filled it back up with 4.5 oz of PAG 100 oil before I installed it.

I used teflon tape on the new charge ports because they had no gasket or O-ring; they just sealed through the threads. For the O-ring connections and the service valve adapter to compressor connections, I used some stuff called Nylog that an HVAC expert friend of mine told me about years ago. It has the consistency of snot.

After I tightened everything down, I spent an hour pulling a vacuum and let it hold for about a half hour, and it held pretty well. I put in two cans of R134a and it blew ice cold. That was Saturday at 10 pm. I haven't actually driven the car since then but I've started the engine a few times and checked the A/C and it has not leaked out, although when I checked it today, it did not seem as cold.

I'm worried that I didnt put enough refrigerant in. I may have rushed through the two cans and not given them enough time to fully empty.

When I was at the end of the second can, I was watching the gauge on the low pressure side. When the can was hooked up and the clutch was disengaged, the pressure rose to about 42 psi, but after the clutch engaged, the pressure dropped to about 25 psi or a little less. The outside temperature was about 85 degrees. What should the pressure be? Do I need to add more refrigerant?
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  #29  
Old 08-12-2020, 08:29 PM
mantonas mantonas is offline
230 Tornado
 
Join Date: Apr 16, 2017
Location: Knoxville, TN
Posts: 19
Oh, I guess it's pretty obvious but I forgot to mention that I transferred the clutch from the old compressor to the new one.

Also, if I had it do do over again, knowing that I was going to end up replacing hoses, I probably would have converted to a Sanden-style compressor. I still might eventually, but at least this way I can get some experience with a York and decide for myself if I hate it.
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  #30  
Old 08-13-2020, 04:36 AM
wiley-moeracing wiley-moeracing is offline
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Join Date: Feb 15, 2010
Location: arizona
Posts: 1,237
your low on r134, what are the pressures when running with system on high/max a/c(high and low)?
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  #31  
Old 08-13-2020, 09:42 AM
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babywag babywag is offline
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what size were the cans?

google has zillions of r134a pressure/temperature charts
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  #32  
Old 08-13-2020, 06:44 PM
Dave Jeeper Dave Jeeper is offline
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Join Date: Sep 08, 2019
Location: Denver, CO
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look up "r134a pressure chart" with google and look at images in the google browser and you will see charts that lists low side and high side pressures for this refrigerant at different outside temperatures.


83 to 93 degrees F the low pressure should be 45 to 55 psi.

The high side pressure should be 225 to 250 at 85 degrees and 250 to 275 at 90 degrees.


When attaching gauges or hooking up a can of freon, it is best to bleed the hose to purge any air, which has moisture in it that can freeze up your expansion valve or expansion orifice if it enters the system. The freon should be added to the low pressure side, never the high pressure side. Have a bucket of warm water nearby. Never turn the freon can upside down, that lets liquid freon into the compressor which can destroy the compressor. When the freon can gets too cold or as the system pressure gets to about 25 psi, freon will not flow very quickly into the system. Place the can in the warm water and the freon will start to flow. Don't use hot water or the can may become over pressurized and explode. I usually use about 90 degree water and I watch the glass port on the gauges to make sure that I am not getting too much liquid entering the system. If too much liquid, then I take the can out of the warm water until the flow in the sight glass slows down, then the can goes back in the water.



I pay more attention to the low pressure when adding the freon, my Harbor Freight gauge set doesn't seem to get the high pressure up to what is listed on the chart. If adding freon to a system that was not empty, then I will add freon until the low pressure gets into the range of the chart for that outside temp. If the high pressure does not reach the lower level of the chart's listed high range, then I will not add any more freon after the low pressure has reached the upper pressure for the chart's low range.


An example of this is: At 85 degrees outside the low pressure should be 45 to 55 psi and the high should be 225 to 250 psi. I add freon until I have at least 45 psi on the low side. If the high side is less than 225, then I keep adding freon. If the low is 50 and high is 225, then I might add a little more or stop adding. If the low reaches 55 and the high is reading 215 on my gauges, then I will stop adding freon because I have reached the upper limit for the low pressure range.



Something to be aware of are the pressure switches on the A/C system. If the low pressure falls below approximately 28 psi, then the low presssure switch will stop the compressor from running. So, if you have 30 psi on the low side with the compressor off, then the compressor comes on and starts pumping the freon to the high pressure side, the low pressure will drop. When it hits about 28 or so, the compressor will shut off. That is why you need more than 30 psi on the low side so that the compressor can keep running.


If the high side pressure exceeds the high switch limit (350 psi?) then the compressor will shut off and the high pressure will drop until the switch allows the compressor to come on again. This happens when there is too much freon in the system or there is an obstruction in the system (bad or frozen expansion valve or orifice typically).


The hotter it is, the higher the pressures will be. I usually try to add freon when it is 90 to 95 degrees out. Then if it goes up to 100, the increase in system pressure should still be below the high pressure switch limit.


One last thing to note, the faster the engine turns, the more pressure the compressor will put out. The chart is designed for idle speeds I believe (I might be wrong on this one). If your A/C is cutting in and out on a hot day on the highway, then the pressures may be too high, even if they don't look that high at idle, due to the higher engine speeds and corresponding higher pressures on the highway. Maybe that is why my high pressure readings are a little low, I am measuring pressure at idle and not at higher engine rpm.


I know this is alot, I hope that it helps.


David
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  #33  
Old 08-13-2020, 06:46 PM
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babywag babywag is offline
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Also check it ~1500rpm vs. idle more accurate pressure readings.
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