67 Dart AC out again.

-
Mopar92

Mopar92

Well-Known Member
Joined
Dec 23, 2015
Messages
1,460
Reaction score
279
Location
Lewisburg tn
If there is one area I never fully learned on the old Mopars, it's the AC side of things. I have a survivor 67' Dart GT with a 273 in it. The AC worked for a little bit when I first got the car 10 years ago. I'm motivated to fix it this spring. The guy who sold it to me had some old school refrigerant left and juiced it up for me. I'm really interested to know where I should look and what I should retro to get it going again. Are the old compressors and evaporators compatible with the newer refrigerants? I'm not really into the GM sanden look of a new compressor but I suppose if that's the logical route, I will accept it. Is this something a do it yourself guy can get back up and going or is this an AC shop only deal? Not sure where to start. Thanks for the suggestions in advance.
 
Hi,

Auto A/C is something you can learn to do yourself. I have been doing my own for well over 30 years. You'll need some equipment, a vacuum pump and a gauge set. You can rent, borrow or buy these things. The factory shop manual fully covers working on the A/C system and you really should have a copy of it.

You will have to decide if you are going to keep the old R-12 refrigerant or change over to newer R-134A. Your old system components will work with either. but, you will get the best performance with R-12. R-12 is still available although you need a 609 permit to buy it.

Changing to R-134A is a bit more involved as the oil in the system will have to be changed to a R-134A compatible type and all the O ring seals will need to be changed to a compatible type. The receiver/drier will also need to be changed to an R-134A compatible type.

Your system is almost 50 years old and if all original I would strongly suggest you install new hoses and O ring seals even if you stay with R-12. I would also change the receiver/drier if it is original.The old Chrysler RV type compressors are very rugged and will last forever with a little care. There is no need to change over to a Sanden type unless you really want to.

The front shaft seals in an RV type compressor will normally leak a very small amount of refrigerant and this was and is considered normal. When these cars were new it was considered normal servicing to have to add some refrigerant after 5 or 6 years.

The original type factory system in my 71 Charger is still working just fine. So, these old systems do work and you can maintain them yourself. I'll be happy to answer any questions you might have.
 
Biggest cause of problems I believe is compressor shaft seal, deteriorating old hoses, and O rings and seals if used at the fittings. Probably two biggest problems is compressor seals and hoses.

You can find R12 if you look around. See if you can find some old guy like me that was in HVAC years ago and has a can of R12. It can be expensive, though

If you are going to do any amount of rebuild to the system, I'd strongly consider converting to R134. At the least you'll need to flush the system and change compressor oil I don't recall what else

As above, you can download factory manuals for free at "MyMopar." It was "down" a few minutes ago. Might be the storm back east.
 
67Dart273 said:
You can find R12 if you look around. See if you can find some old guy like me that was in HVAC years ago and has a can of R12. It can be expensive, though
Click to expand...

I wasn't a HVAC guy but I am old lol! I have a couple cans of R-12 that I probably will not use, but no idea of what they're going for.
 
Mopar92 said:
Saw them at a swap meet for about $30 a can recently.
Click to expand...


That seems to be about the going price for R-12 these days. R-134A is going for about $10 a can.

One thing to keep in mind is that R-1234yf is supposed to be coming for the 2017 model year cars. This supposedly more environmentally friendly refrigerant is reported to be around $60 a pound and supposedly not going to be available to do-it-yourselfers. R-134A can be used to replace R-1234yf. It would be a no brainer to simply use R-134A if a R-1234yf system needs to be completely recharged. I suspect for this reason while R-134A will not go away I would expect its price is going to go to the R-1234yf level to avoid people using R-134A to replace R-1234yf.

With this being a possibility, I would think twice about converting a R-12 system to R-134A now. In the long term R-12 may prove to be less expensive.

Be careful with swap meet or Ebay R-12. Make sure it is real R-12, not R-12A. There is no such thing a R-12A. What is being sold as R-12A is really a mix of R-134A and other refrigerants to carry oil around the system. These "blends" have their own set of problems and should never be added to systems containing real R-12.
 
Pete in NH said:
That seems to be about the going price for R-12 these days. R-134A is going for about $10 a can.

One thing to keep in mind is that R-1234yf is supposed to be coming for the 2017 model year cars. This supposedly more environmentally friendly refrigerant is reported to be around $60 a pound and supposedly not going to be available to do-it-yourselfers. R-134A can be used to replace R-1234yf. It would be a no brainer to simply use R-134A if a R-1234yf system needs to be completely recharged. I suspect for this reason while R-134A will not go away I would expect its price is going to go to the R-1234yf level to avoid people using R-134A to replace R-1234yf.

With this being a possibility, I would think twice about converting a R-12 system to R-134A now. In the long term R-12 may prove to be less expensive.

Be careful with swap meet or Ebay R-12. Make sure it is real R-12, not R-12A. There is no such thing a R-12A. What is being sold as R-12A is really a mix of R-134A and other refrigerants to carry oil around the system. These "blends" have their own set of problems and should never be added to systems containing real R-12.
Click to expand...

One other thing to throw out there is R-152A. It's supposed to have a very similar pressure/temperature curve to R-12 and is compatible with the newer PAG oil used for 134A. It's super cheap (can duster DIFLUORETHANE) and I have read lots of good things about it. Haven't tried it yet myself so I can't comment on that. Something to research/consider.
 
R-152A has a pressure/temperature curve somewhere between R-12 and R-134A. So, it transfers heat a little better than R-134A but not quite as good as R-12. It is supposedly environmentally friendly but is not used in automotive A/C systems because it is flammable and poses a fire hazard. There was some work done with R-152A when R-12 was going to be phased out but, these were double loop systems. The R-152A was kept under the hood on the engine side of the firewall and used to cool a secondary loop of water or brine solution that was linked into the passenger compartment. Needless to say this was a much more expensive system and R-134A won the R-12 replacement battle.
 
Also be careful of "shysters" People are selling all kinds of crap (with propane?) and calling it an R12 replacement, and labeling it "something dash 12".
 
I guess I need to find the leak first. Is there a diagram that shows all of the o rings?
 
If it's a factory system, the only good places, in no particular order are

1...Factory service manual, which you can download free at MyMopar

2...Factory parts catalog, which is hard to read, same as above and ebay

3...Pictures on the net, IE here, there, wherever you find them, of members engine bays.

Main things I'm referring to should be obvious.......hose end fittings, the hoses themselves, IE leaking right through the hose material and or the crimp, and compressor fittings and compressor shaft seal. If the system has a sight glass, that can leak, and whatever switches, IE low pressure cutoff can leak.

The condenser can leak from things like rock / debri damage, of course at the hose fittings/ or from simple corrosion or vibration damage.

The evap can leak at the hose fittings, and from corrosion. or vibration damage

I would find / buy / borrow / other a leak detector. you can occasionally find the old "halide" torches cheap at garage sales, CL, and probably ebay. These are actually quite effective. They are an LP (propane) torch with a copper piece in the burner, and a draft hose. You want to carefully adjust them down to a very small flame, and use them in subdued lighting. When you pass R12 type refrigerants through a flame, the copper and flame causes a color change from bluish to greenish.

https://www.google.com/search?num=2....0....0...1c.1.64.serp..0.12.1084.yc33x8jqq2A


Of course these do not work with the new "friendly" refrigerants.
 
Those flame/torch leak detectors only work for R-12 and that is assuming there is any R-12 left in your system. There may be some charge left but just below the level needed to keep the low pressure cut-off switch from operating. Try removing one of the service fitting caps and depressing the center of the valve if you hear a slight hiss the system still has some R-12 in it. If not it is basically completely empty.

When refrigerant leaks out it will carry some oil out also most of the time. This oil will then attract dirt that will stick to it. Look for an oily accumulation around fittings and you may have found a leak.

Remember, as mentioned above, RV compressor shaft seals will leak a very small amount of refrigerant and over a long time the system will be discharged.
 
Pete in NH said:
Those flame/torch leak detectors only work for R-12 and that is assuming there is any R-12 left in your system.
Click to expand...

Thanks I intended to make that clear. Actually they work for ANY of the old traditional "chloro" based refrigerants, R12, 22, 502, 500, R11, etc etc etc. I realise we are dealing with R12/ or "other" here.
 
You must log in or register to reply here.
-

Back
Top