66 Monaco Wagon A/C Resurrection (I Hope)

[TxDon]

I found my 66 Monaco wagon about a month and a half ago, it is a mostly original car with high miles but has been well cared for. I have been posting to another preservation thread here which includes many photos if you are interested: 66 Monaco Wagon Preservation

The most immediate challenge on the car is that the factory A/C system does not work and since I live in the DFW Texas area that is cutting into my driving and enjoying the car. I have decided to attempt my own repairs to get it working so I also decided to start a separate thread here. I have done a lot of searches here and have read a lot of other threads and posts which have been helpful as I see a whole bunch of you have had the same challenges.

Briefly, here is where I am right now. The car has the factory dual air system with the separate evaporator /fan unit hanging from the rear roof and it was converted successfully to R134A about 6 years ago. All original parts are there, all switches and controls work as they should, the compressor engages and turns without weird noises, but it just does not cool. There is some refrigerant in the system, not sure how much. My plan is to leak check, do minimal repairs, and recharge to see if it will work as is.

I have bought some tools and supplies such as a gauge set, vacuum pump, conversion ports, refrigerant, etc. and am still researching to come up with a good step by step set of instructions before I start. I will be posting the questions I have here as well as doing a play by play of how it works.

My first question is about the stock RV-2 compressor and refrigerant oil. The FSM describes being able to check the oil level through the "crankcase oil filler opening" but does not show where it is. Can someone post a photo or describe where it is? Also, is it possible to drain the oil out of the compressor while it is mounted in the car? IF so how is that done? Thanks!

 

[livininharrow]

do yourself a favour don and have a qualified a/c guy check it. you can buy all of the tools you think you may need and still be at a loss. nobody can teach you how to do refrigeration or a/c work over this or any other forum. you can hurt yourself or somebody else. not trying to tell you what to do but trust me on this one.

 

[Davea Lux]

Livininharrow is correct, there are a lot of things that can go wrong here. RV2 compressors lose refrigerant oil over time and the only accurate way to fix a low oil issue is to discharge the system, recover the R-134a and oil and then put a proper charge of both back into the system. If the system is low on refrigerant, most likely there is a leak someplace that needs to be repaired before recharging the system or you will be back into the same place in a month or two. Just adding oil to the system can result in the pistons in the RV2 compressor slugging oil if too much is added, this can result a catastrophic failure of the compressor. Adding too much R-134a can result in a high pressure situation that can blow out a hose , a line, an evaporator or a condenser and potentially injure yourself or some one else. Adding too little refrigerant will cause the refrigerant oil to stop circulating and burn out the RV2 compressor. A system that has been discharged due to leakage also needs to have the filter dryer replaced prior to be recharged. Any moisture in the system is highly destructive and will cause the control valves in the system to freeze up and stop working, moisture also quickly degrades refrigerant oil and turns it into sludge.

To answer your original question, the compressor oil can be checked. First the refrigerant charge has to be removed. On the passenger side of the compressor, there is a plug on the side of the crank case. This plug is removed and a steel rod is inserted into the hole until it hits the bottom of the crank case. The FSM gives guidelines on how to measure the volume of oil relative to its depth on the metal rod. THIS PROCEDURE CAN NOT BE USED ON A SYSTEM THAT HAS BEEN RUN LOW ON REFRIGERANT AS MOST OF THE OIL HAS CIRCULATED OUT OF THE CRANKCASE AND INTO THE REST OF THE SYSTEM! The reading achieved will not, therefore, be accurate.
There is no way to drain oil from the compressor via a drain plug, oil removal is accomplished using vacuum which boils the oil as part of the discharge process.


Dave

 

[TxDon]

Well that's not very encouraging. Thank you both for your concern but I can assure you that any work I do will include the proper service procedures and safety equipment. I research something like this extensively and not just through forums.

I did find the information on checking the compressor oil using a fabricated dipstick. Interestingly it was not in my 66 Monaco Shop Manual but was in my 67 Plymouth manual.