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Discussion Starter #1
Hey guys,

my Voyager´s AC compressor is shot, new one is on its way.

Is there anything to knwo about a complete refilling? Is R 413a acceptable for the old R12 system? Which oil is needed?

Thanks again!
Kevin
 

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I changed my '86C and '88GC over to 134 with no problems.

On the 86' I just added 134, on the '88 I had to replace the comp so I changed to the correct oil also. Using the correct oil is the only real issue I know of but I didn't change it on the '86.

No problems with either one and those changes were in '05.
 

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One note, if you have rear AC the R134 will not work very well on 92' and older vans.

My neighbor has a 92' with 360k miles and has overhauled the AC a few times, the first time tried the r134 route best temp out the vent was about 55-60 degrees, no matter what he tried. Finally cleaned out the system and put r12 in(at a high cost) and it works great. The condenser is very small prior to 93' and with the added rear AC it just can not disapate enough heat.

If you have just front AC you should be fine, we switched both of my grandmas 86's over to R134 and they worked great.
 

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Anytime that you open the system, you must replace the drier canister (dessicant). Converting is not always straightforward. If the compressor is shot, there may be debris in the lines and expansion valve. Did it seize, or have bearing noise? If it seized, you really need to flush the entire system and re-oil it with ester oil - about 4-6 oz total. Ester oil is for conversions, PAG oil is for systems that were always R134a. Using PAG in an R12 system that is not flushed *completely* clean can cause clogs. Regardless, when it's all back together, you must draw a vacuum with a vacuum pump, down to 29 inches or better for at least an hour - longer is better. Once it holds vacuum, then you can refill with R134a, to about 85% of the R12 capacity. You will want gauges on both sides as well as a vent thermometer to assess how it's working when it's near full.
 

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1st generation mini-vans do not convert real well to R134a because of efficiency loss. If you are in a temperate climate, you may be OK, but where I live, such conversions are usually less than satisfactory. Part of the problem is due to the small condenser used on Gen 1 minivans (it is not in front of the radiator, but off to the side). You can make a little improvement by using a better fan to move the heat away from the condenser. In 1989 Chrysler did have a better condenser fan for the min-vans and I made that change to my 86. I just had to cut off the plug/connector on the newer fan and solder on the piece from the older fan to get it to plug into the wiring harness.
 

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It all depends.

My '88 cools as well as my wife's Cad on 134 and it is definitely hot and humid here in Arkansas! Not like FL though. My center outlet temp is 40*F at 90-100*F. Always run it on MAX or Recirculate for much better efficiency.

The one thing I did carefully was measure the correct amount of the correct oil in both the comp and drier.

Except for slightly higher pressures for 134 I can't tell any difference in it and R12.

I don't think '88s had rear air but don't quote me on that!
 

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Discussion Starter #7
Bob Lincoln said:
Anytime that you open the system, you must replace the drier canister (dessicant). Converting is not always straightforward. If the compressor is shot, there may be debris in the lines and expansion valve. Did it seize, or have bearing noise? If it seized, you really need to flush the entire system and re-oil it with ester oil - about 4-6 oz total. Ester oil is for conversions, PAG oil is for systems that were always R134a. Using PAG in an R12 system that is not flushed *completely* clean can cause clogs. Regardless, when it's all back together, you must draw a vacuum with a vacuum pump, down to 29 inches or better for at least an hour - longer is better. Once it holds vacuum, then you can refill with R134a, to about 85% of the R12 capacity. You will want gauges on both sides as well as a vent thermometer to assess how it's working when it's near full.
Well, that´s interesting to read! So a complete change to R134a is possible without replacing or changing any gaskets?

My compressor isn´t seized, but the bearing is very noise, so i removed the AC belt. Also the system is completely empty. I just ordered an overhaul kit for the compressor, including a bearing, clutch and the gaskets.
 

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you really should get the system flushed. Metal debris from the bad compressor could mess all the new stuff up. Oreilly's sells an R12 conversion kit with everything you need including 3 cans of freon.
 

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If you can turn the comp by hand a flush is not necessary and I mean the comp not just the pulley. If it is seized a flush is mandatory.

Gaskets don't care. Oil does, although there is an oil that works for either/both. I forget the name of it, it has been a while since I did this work. It has been a long time now since I've had any AC problems except for an occasional top off of 134 - knock on wood!

Please carefully follow the oil amounts recommended in the O/H kit. It is much different for a system that hasn't been flushed and one that has. All compressors need to be drained of oil before refilling, even new ones, so the correct amount can be used. It is far easier and accurate to do while out of the van.

Same story for driers although I don't think they have oil added when new. Ditto for the drirections for the drier.

I strongly reemphasize what Bob said about complete evacuation. If you don't do this it will quickly fail. AC systems cannot tolerate moisture (air). If you don't do this you may as well not even do the work. It also shows if you have a leak.

Any hoses must be cleared of air and filled with freon before allowing freon through them into the system. Not necesary if just checking pressures.

My worst experience with 134 ihas been overfilling when going by gage pressures. I finally just used the thermometer in the central AC outlet as my guide - when the outlet temp gets down to the proper temp relative to the outside temp I quit filling with freon. This has worked well for me for all these years. You will find these temps in your van maint manual.

This is not a complicated job but there is definitely a learning curve, the little things get you!

One of those is don't connect the can to the low side unless it is completely cold and even then it is not a good idea because the pressures can be too much for the freon can. Low side is always a safe pressure with the comp running. The only exception is when the system is empty/almost empty or while it is evacuated, then you can send freon directly into it with the comp not running.

Also, you will need to jump the connector to the low pressure cutoff switch on the low side line. This is to keep the compressor running until it has enough freon pressure to run on its own. Do that after freon will no longer flow from the can with the comp off.

Adjusting the clutch clearance is critical, and a real pain. I stopped doing that and just buy a rebuilt comp which is not much more costly than the clutch alone. Rebuilding a comp is not worth the effort in my opinion. After all that work something else can fail and a rebuilt comp has a warranty - kits don't. Not trying to rain on your parade but that has been my experience. Even better is a new comp but they don't seem to last much longer than the rebuilts.
 

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Discussion Starter #10
Well thanks for the input!

Only thing we have here are those filling valves for the R134a, cause they use a different one than on the old R12 A/C´s. But that should not be the problem.
 
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