RV2 gas capacity

[carlv12]

Hello,

My 1974 Plymouth Fury Sport Suburban has a RV2 compressor. The sticker on it shows 5 lbs of R12 gas, that means that I should fill in 80% of the new R134a gas, because in Europe R12 is totally forbidden.
5 lbs seems to be a lot, but my mechanic says that iy is a very large Station Wagon with a lot of space that muts be cooled.

Are 5 lbs the correct charge capacity?

Thank you and best regards from sunny Valencia

Carlos

 

[TxDon]

Unlike R-12, R-134 should be charged based on high - low pressure readings rather than weight, buy or borrow a good gauge set and research the R-134 pressures.

 

[413]

See that little Phillips head screw? That tag could have been changed. Look in the factory service manual for the charge amount.

As stated above the best way is going by what the gauges read when operating, but the system must function correctly for that to be right.

 

[carlv12]

See that little Phillips head screw? That tag could have been changed. Look in the factory service manual for the charge amount.

As stated above the best way is going by what the gauges read when operating, but the system must function correctly for that to be right.

Hello,

Unfortunately I do not have the service manual, therefore I ask you here in this Forum...

I hope that there will be Mopar experts that can confirm that 5 lbs of R12 were correct when the car was new. See a betrer pic of the sticker.
Thank you again and best regards from Valencia (Spain)

Carlos

 

[Davea Lux]

Per the service manual, 4lbs 6oz is the correct charge of R-12 with the dual unit A/C. One would expect the R-134a charge to be about 80%-90% of that. Some notes: 1.) RV-2 compressors have a very high failure rate running R-134a because the lubricating oils do not circulate well with R-134a. This gas is a lot less dense than R-12 so it does not move the oil as well. This is especially true on dual unit systems because the oil tends to get trapped inside the rear unit. 2.) All of the R-12 and R-12 oil must be removed from the system prior to recharging with R-134a. The gasses and the oils are not compatible. R-12 oils (mineral) left in the system turns into a yellow goo that does not circulate if exposed to R-134a. Filter dryer must be replaced and the entire system should be flushed to remove all of the R-12 oil. A competent shop should be able to do this for you. All of the black o-rings should be replaced with the high density green ones to reduce leakage. The barbed type hose connectors on the suction hoses also sometimes leak because the barbs pierce the inner barrier of the hose. The R-134a molecule is smaller and will leak in places where R-12 does not. 3.) The tag should not be relied on for the charge amount as the compressor is a universal unit that had many possible applications as noted above. 4.) If the system is currently discharged, this would be a good time to do the Sanden conversion since the vane type compressor will live with R-134a. There are several posts on this site about this conversion.

www.mymopar.com has the service manuals available for free download in the Tools/Reference section. The Fury, Polara and Chrysler cars all use the same A/C system if your specific model is not listed.

Dave

 

[carlv12]

Hello Dave,

My car has only a single AC system, NOT a dual one. Are then 5 lbs of R12 and therefore 80% of R134a wrong and that would explain that after 5 minutes on aroad trip just after charging the system with 80% R134a = around 1800 g the compressor stopped working and I could see huge leaks of the R134a gas.

The service manuals show between 3 lbs 2 oz (1417 g) and 3lbs 6 oz (1530 g) for the single AC system, that would be again taking 80% of R134a between 1134 g and 1225 g.

Do these leaks make sense if we have charged my single AC system with the wrong charge capacity of the dual AC system thinking that the 5 lbs sticker shwos the correct capacity?

But my sticker shows 5 lbs and it says SINGLE UNIT, so are 5 lbs correct or not? It's totally crazy and makes no sense - I do not understand why my sticker says 5 lbs....


Thank you and best regards from Valencia

Carlos

 

[Davea Lux]

Someone has installed a rep0lacement compressor with the wrong tag. Use the numbers in the FSM and adjust to start. You can adjust to get to the right pressure numbers.

Dave

 

[CBODY67]

When the conversions to R-134a were first being done, the 80% charge level for R-134a is a starting point, NOT the ending point. R-134a is more sensitive to an over-charge than R-12, too. So, the recommendations were to put a freon recycling machine for R-12 on the car to flush the system and remove any oil, too. Once that has been done, then put the R-134a machine on the car, evacuate the system (after replacing the receiver dryer and such), then charge the system to the 80% level. Then . . . start the car and run it until everything's fully up to operating temperature. With the engine at about 1500rpm in "P", check the a/c vent output temps (front windows down and fan on highest speed, possibly with a big fan in front of the car, blowing air into the grille), then very slowly add more R-134a gas until the vent temps hit their lowest level, then STOP adding gas and note how much more past the 80% level that charge is. In many cases, as I understand it, the ending amount was close to the 90% charge level of R-12.

With R-12, the target coolness from the a/c vents was approx 40 degrees F, but with R-134a, it might be a few degrees F higher.

As a general rule, most C-body single systems usually took about 3.5lbs of R-12 gas. As almost everybody else's single systems did back then.

Just some thoughts,
CBODY67

 

[carlv12]

Hello,

Then the sticker with 5 lbs of R12 charge capacity is wrong for my car, but is there any Mopar car from 1974 that had 5 lbs with a single AC unit?

Thank you and best regards from sunny Valencia

Carlos

 

[3175375]

Hello,

Then the sticker with 5 lbs of R12 charge capacity is wrong for my car, but is there any Mopar car from 1974 that had 5 lbs with a single AC unit?

Thank you and best regards from sunny Valencia

Carlos

Could have been in a bus, RV ?

 

[volksworld]

where did the gas leak out? did it blow out the plug on top of the reciever/ dryer?....where ever it leaked out needs to be fixed

 

[Davea Lux]

Hello,

Then the sticker with 5 lbs of R12 charge capacity is wrong for my car, but is there any Mopar car from 1974 that had 5 lbs with a single AC unit?

Thank you and best regards from sunny Valencia

Carlos

Probably a motor home with the large evaporator mounted on the roof.

Dave

 

[TxDon]

Hello,

Then the sticker with 5 lbs of R12 charge capacity is wrong for my car, but is there any Mopar car from 1974 that had 5 lbs with a single AC unit?

Just to put it in perspective my 66 wagon has dual unit A/C and this was the stock plate on the compressor, capacity 3 lbs. 14 oz.

 

[carlv12]

Hello again,

my mechanic fitted finally another RV2 compressor and we installed a new crankschaft seal from classic industries. Then he put 80% R134 of 3 lbs 6 oz to try fisrt, but the pressures were a lot too low!!!!! That means that for this car 3lbs 6 oz of R12 = 80% R134a are not enough.

The most imoprtant part come now: I could contact the actual owner of another car like mine, mine has the number plate M 3003 AG and his one M 3002 AG, that means that both identical cars (Plymouth Fury Sport Suburban from 1974) were bought in 1974 by the same owner and now comes the interesting part: his car has excatly the same AC charge sticker with 5 lbs!!!!!!!!
I cannot imagine that two cars that are even in the USA rare and here in Spain they are the only ones, have both the same wrong sticker. Both cars where sold the first time in Spain, with odometer in km/h and rear orange turn signal lights. My question now is: has anyone of you this sticker on his car or has seen it an another car? Please post a picture and tell me from which car it is.

What do you think?

Thank you and best regards from Valencia

Carlos

 

[3175375]

Hello again,

my mechanic fitted finally another RV2 compressor and we installed a new crankschaft seal from classic industries. Then he put 80% R134 of 3 lbs 6 oz to try fisrt, but the pressures were a lot too low!!!!! That means that for this car 3lbs 6 oz of R12 = 80% R134a are not enough.

The most imoprtant part come now: I could contact the actual owner of another car like mine, mine has the number plate M 3003 AG and his one M 3002 AG, that means that both identical cars (Plymouth Fury Sport Suburban from 1974) were bought in 1974 by the same owner and now comes the interesting part: his car has excatly the same AC charge sticker with 5 lbs!!!!!!!!
I cannot imagine that two cars that are even in the USA rare and here in Spain they are the only ones, have both the same wrong sticker. Both cars where sold the first time in Spain, with odometer in km/h and rear orange turn signal lights. My question now is: has anyone of you this sticker on his car or has seen it an another car? Please post a picture and tell me from which car it is.

What do you think?

Thank you and best regards from Valencia

Carlos

View attachment 558344

Possibly the answer.

HOWEVER, R-134a should be charged using the high and low side pressures and outside air temperature, not an amount.

If your mechanic doesn’t know this, you may want to do it yourself or find another mechanic!

 

[CBODY67]

The "80%" level is only the STARTING POINT, not where things ultimately end up. Start at 80% and slowly add gas until the cooling air out of the dash vents gets to its lowest level, then stop. The end result, IIRC, is closer to 90% than 80%, but you have to start low and build rather than otherwise. The old R-12 aim for air coldness out of the dash vents is 40 degrees F, but with R-134a, it can be a bit higher.

CBODY67