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Help a newbee

v194 on Mon March 24, 2008 11:17 AM User is offlineView users profile

Year: 1970
Make: Plymouth
Model: Cuda
Engine Size: 340
Refrigerant Type: r12
Country of Origin: United States

My mechanic told me that my compressor was leaking profusely from a seal and suggested that I get a new unit. He confessed that he has had little success in replacing the seals and having them hold up over time so he suggested a new/rebuilt compressor.

I got me new unit and he suggested that I need to fill it with the proper lubricant. Its now only filed with trace amounts of assembly lubricant as the instructions state that came with the unit. He gave 1/2qt to use as fill. He stated that i would need to consult the factory manual to see the correct amount and where to add it. Anyone know what they might be? He also suggested I get a new Accumulator/Drier, and Expansion Valve. He said to add about 1 oz of the oil to the Drier when I installed that as well.

This is an all R12 system and since it is on a vintage car I have to use factory correct parts (in appearance and look) so I cant update to a sandsen style system or change the condenser to a non factory looking unit.

I want to install as many of the parts as possible and allow my mechanic to "finish" the project. That is fine with him.

Anything I am overlooking or missing and I welcome any advice you may offer.


JJM on Mon March 24, 2008 1:21 PM User is offline

What compressor do you have? I assume it's the AirTemp RV2 as pictured below:

Remanufactured Compressor Without Clutch

With a rebuilt compressor somebody sucessfully (hopefully) replaces the seals, so why not you? And many chain store rebuilds will probably be worse than what you have now. But if you would rather replace the compressor, I would strongly suggest compressor from the sponsor of this site.

By all means, replace the receiver/dryer, and it wouldn't be a bad idea to replace the TXV as well, though not necessary unless defective. But you should also thoroughly flush the remainder of the system, replace all rings, and hoses... after 38 years they're just waiting to burst. If you're sticking with R-12, I assume this will be 525 (or 500) mineral oil. POE would be OK as well (though not original spec). PAG of any grade is a no-no.

I will have to get back to you as to what the oil and R-12 specs are for your vehicle... don't have that info right now.


When considering your next auto A/C purchase, please consider the site that supports you:

mk378 on Mon March 24, 2008 2:25 PM User is offline

If it's the one JJM posted, that type of compressor has a crank and pistons like a v-twin engine. Most of the oil stays in the crankcase in the bottom, which you can access thru the oil plug in the side. The refrigerant must be removed to zero pressure before unscrewing the oil plug.

v194 on Mon March 24, 2008 6:47 PM User is offlineView users profile

Yes it is the RV2 style

I already have a new unit so no problem there however the new unit only has assembly lube in it and nothing else hence my asking about the mineral oil level. The old unit is without pressure on it now. I should point out it was functional last year after being dormant since the 80's. My mechanic pulled a vacuum test to see if it would hold and it did fine. So with that test he filled it with R12 and it started to cool fine. We had a electrical problem not suppliying and power to the high side (?) I think that is what he said. The switch coming to the evap canister. The switch was fine but no current was running to part of it so it would not cycle up. When that was corrected months later (I don't drive it much) it was no longer cooling. So he filled with a tiny amount of r12 and compressed air and ran the scope and it started to signal as he neared it to the compressor. Again he felt that replacing the seal was not best so he suggested a new unit.

I plan to order the evap and other parts from this sites sponsor. I just want to make sure I have all I need.
Thanks for the suggestions and keep them coming.

JJM on Tue March 25, 2008 12:22 AM User is offline

Oil: 8 ounces max (6 ounces min). Corresponding dipstick level on bench 2 3/8" for 8 ounces and 2" for 6 ounces, as MK notes. Amazing how you could check oil level on the antiques with a simple dipstick, and on "modern" vehicles it's all guesswork unless the system is dry.

Refrigerant: 3 1/4 pounds of R-12.

340 motor... I seem to only remember a 225, 273, 318, 361, 383 and the nice 440 of that era... 340?

I'm not entirely sure this compressor is supposed to cycle. Most of the AirTemp RV2's had an EPR or ETR valve built into the compressor on the suction side, which controlled evaporator pressure much like a STV or POA. If your unit IS indeed supposed to cycle, please be sure to remove the EPR or ETR on the suction side, as many RV2's will have them. The EPR goes all the way back to 1961, mostly on full size Chryslers. These systems use a 3rd gauge for diagnosis.


When considering your next auto A/C purchase, please consider the site that supports you:

v194 on Tue March 25, 2008 8:23 PM User is offlineView users profile

The 361 was last used in a passenger car in 1966 but remained for trucks until 1972. I believe it was the smallest. The 340 came in passenger cars (Dart and Barracuda in 1968) it remained until 1973 and was essentially replaced by the 360 cubic inch.

Ill have to take a close look at the EPR ETR.
Thank again -

v194 on Thu March 27, 2008 8:30 PM User is offlineView users profile

Another question
I want to order the expansion valve and the drier from
How do I know which is correct for my application? They list two ex valves?
Im running r12

Chick on Thu March 27, 2008 8:49 PM User is offlineView users profile

It's a little hard to explain, but I'll give it a shot... Older Chryslers sometimes have an "indentation" in the line where the sensing "rod" goes into it. Look at where your sensing bulb attaches to the line, does it appear to go into the line? If so you have the one with the straight end. If it attaches to the line and is clamped and covered with the insulation, the one with the corkscrew bulb is what you need. Wish I had a pic when the last one was in the shop...

The one that goes in the line looks kinda like an IV needle going into a vein.... hope this helps..

Email: Chick


Freedoms just another word for nothing left to lose

Edited: Thu March 27, 2008 at 8:50 PM by Chick

v194 on Thu April 03, 2008 8:30 PM User is offlineView users profile

Well I ordered one from the sponsor of this site and it arrived today.
I ordered based on the sites photo description this part number 31-10970 But what arrived was what looks just like 31-10928 with R134a clearly spelled out on the unit.
I assume they take returns?
How to do this?

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