67 Charger Factory AC Problems

[gibber]

Just finished up a 3 1/2 year restoration project on my 67 Charger about 6 months ago. Since then I've tried twice to get the factory AC charged. The system is all new: AC heater box (Classic Auto Air), new hoses, evap/dryer, expansion valve, condenser. The first shop that worked on it said the compressor was not working correctly, so I pulled it off and sent it back to Airparts in TX. They told me there was junk inside the compressor and it could not be rebuilt. Interesting since I bought the compressor, evap/dryer and expansion valve from them as a package and it just sat in a box in my garage cabinet for a year and a half before I installed it......

Anyways they sent me another rebuilt unit and 8 oz of compressor oil, so I filled it up with 8 oz, and reinstalled the compressor. Took it to a shop today and same thing, vacuum held for 30 plus minutes, no leaks, and when they tried to charge the system, compressor wasn't working correctly again. Shop says to pull the compressor, drain the oil, flush the system to get rid of any old oil, replace the expansion valve and try charging it again. Their theory is there is way too much oil in the system and that is what is causing the low pressure out of the RV2. When I told the tech today I had filled the compressor sump with 8 oz he winced....so I'm wondering if anyone here has any AC expertise they would like to share....

This is the last item still needing attention (for now anyways...you know how that goes)...

Thanks in advance,

Mark

 

[red72]

Do you have an epr in your new compressor?

 

[gibber]

No, the guy at Airparts told me the EPR valve was not required for this OE application...

 

[red72]

I would agree that the system should be flushed, the txv should be replaced as well as the filter/ drier. Change the oil in the compressor and fill it with 8 to 10oz. of the proper oil. The system should be leak tested with pressure (dry nitrogen) to determine that the system is leak free. Holding a vacuum does not indicate the absence of a leak. Once the system has been leak tested, pull a good vacuum and weigh in the charge of refrigerant. (Are you using 134a?) Run the system for 5 to 10 minutes on max ac with the windows down in a warm area to load the system. This will give the txv enough time to start feeding properly. If the suction pressure is higher than normal and the discharge pressure is too low, the compressor is not pumping properly. A normal evap pressure should run around 40 psig and the discharge should run about double the ambient temp. plus ten percent of that total. That will get you in the ballpark. I recently got the ac on my Satellite working and the first reman compressor I got would not pump properly. Seems that these remans are about a 50/50 proposition. The replacement I got pumped great and the system works well. If I had it to do over again, I would have gotten a reman from Vintage Air out of Tampa. Also, if you have removed the epr, you may need to install a thermostat to cycle the compressor to prevent the evap. from freezing up. This has not been a problem for me, but I don't drive great distances with the ac on. Good luck!

 

[vin_vl29u]

To much oil, pressure will be high with poor cooling. 2 bad compressors in a row, possible. If the 2nd compressor is good (not damaged like the 1st), I'd really look into the expansion valve. Maybe one of the expansion tubes got damaged.

 

[gibber]

Thanks very much for the info....shall get a new expansion valve and dryer, and follow the steps you recommended...

Thanks again,

Mark