AC Compressor Not Working in my 67 Charger

[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

[Pete in NH]

Hi Mark,

I just returned from a vacation trip and saw your post.

Most A/C shops today don't know anything about these old RV-2 compressors.  8 to 10 oz. of oil is the correct amount for an empty system fill if there is no oil trapped in other system components. You mentioned "low pressure" out of the compressor, what were the pressures they were seeing? Also, What refrigerant are you using R-12 or R-134? Need a little more information on what was meant by the compressor "not working correctly"

[John_Kunkel]

I'd want to know specifically why it wasn't "working correctly".

[gibber]

I actually found a what I think to be a knowledgeable AC shop here in Phoenix. We discussed what had been done to date, so here is where I am now.

Purchased an OEM condenser, and will install it but leave the ends capped...
Bought a new receiver/dryer and expansion valve, will install those before I take it over to this shop.

System has 134 fittings and the compressor oil is for 134 systems. My 66 Charger has the same set up with 134 and I get 52 degree air out of the vents, so I know the RV-2 will work....

More to follow once I take it over for another look from someone who understands these old AC systems...

[Pete in NH]

Mark,

When you install the new receiver/dryer  and expansion valve make sure no open lines are left uncapped. Since you will be installing the condenser but not connecting it, cap both the condenser inlet/outlet fitting to keep out dirt and also cap the open condenser lines so the receiver/dryer does not absorb moisture.

Since you are changing the condenser, you might want to consider a parallel flow type which will give you better performance with R-134.

[gibber]

Thanks for the info Pete! Appreciate the help!



Mark

[J.Bond]

Mark;

That first compressor was probably fine until you fired it up for the first time. Then when it was fired up it , sucked that debris out of your EVAPORATOR. I assume at first you tried to use the factory evaporator and condenser coils, and nothing wrong with that however, both coils must be flushed entirely, meaning, absolutely clean. The original R12 system used mineral oil, which is not compatible with R 134 and has to be removed. Seeing that the evaporator is in it's location, and is now a little more difficult to clean, your only choice would be a A/C flush kit preferably aerosol. If your system held a vacuum for 30 min, chances are both coils are fine. If you want or need to keep the original look to the car ,use the original condenser coil, it will work with R 134, but the performance will be down by around 8 to 12 percent, usually noticeable at idle, anything above idle will work fine.

So, if you did mot flush your system, any mineral oil left in the system from day one, that is now contaminated with moisture, oil is hygroscopic, and debris, dirt and insects. will end up going thru your system. Anything that was in the condenser would plug up the thermostatic expansion valve strainer resulting in a running in a vacuum mode, compressor running in vacuum mode is simply that, the compressor is running, you are adding refrigerant, and the suction side is not reacting. Staying on the vacuum scale of the suction gage. Another story if that is the problem.

This is not a too much oil thing, probably nothing more than, a too much crap, left in the system, thing. Do not use compressed air to blow out the system,  use nitrogen if available, if you cannot find an aerosol flush kit.

[gibber]

Thanks for taking the time to reply James. I had Classic Auto Air completely rebuild the AC heater box, so you still think somehow crap got into it? I'm going to take the car down to these AC experts I found after I replace the condenser with the correct factory unit. I'll plug all the lines and let them correctly flush the system. I have a new receiver dryer and expansion valve as well. Thanks again for the info, greatly appreciated!

Mark