<VV> 66 A/C Question

[Frank DuVal]

Notes:

1. Engine compartment must be sealed up on 66, 67 models. Tape rust 
holes! That worked for me...

2. Remove backup lamp assembly and run hoses through the hole, tape 
openings closed.

3. Sight glass should run clear when the charge is enough (or too 
much!), while compressor is running.

4. White bubbles usually means not enough R-12 yet. How many pounds have 
you put in? Note, some cans are only 12 ounces. System holds about 4.5 
pounds.

5. Tighten the belt. 200 psi is nothing in high temperatures. If it is 
squealing at 200 psi, something is wrong, start with loose belt. There 
is a reason there are so many braces on the old A-6 compressor. Clutch 
should easily handle 350 psi, but hope you never see that. If it slips 
at 200 psi, it is bad.

6. I do not have a set of gauges in front of me, but the low pressure 
side should run about 35 degrees F. , whatever pressure equals that on 
the gauge face. Anything lower than 35 and the evaporator can freeze up. 
Or so.... AT least the center dash outlet should not be below 35 degrees 
F. Shoot for high 30s to 40.

7. Temperature is actually controlled by thermostat cycling the 
compressor, but the charge has to be near correct for that to operate 
properly.

8. The rubber seals on top and bottom of condenser are very important. 
So is taking the condenser off the firewall and cleaning all the 
leaves/junk out from behind it. Also blow through the condenser to clean 
the fins. And comb the fins where they usually get flattened.

9. If you run the compressor with the engine lid open, pressure will get 
too high and rupture a hose or worse. Note, this can cause blindness if 
refrigerant gets in your eyes.

10. Old seat of pants rule, if sight glass runs clear with compressor 
on, then bubbles form about 2-5 seconds after compressor cycles off, 
charge is fine.

11. If center outlet temperature is high, low pressure is high, and 
sight glass does not get bubbles after compressor shuts off, system is 
overcharged. Hopefully you never get that far.


Others may have different rules or observations...

Frank DuVal



On 8/17/2016 9:14 PM, Garry via VirtualVairs wrote:
> Hi all,
>
>
> Questions for all the A/C gurus out there. My 66 110hp/pg Monza with 
> factory A/C won't cool. The system was disconnected, but still sealed, 
> with pressure, for  few years, and I am slowly putting it back 
> together. Tonight was final recharge night. Pulled a successful vacuum 
> last night, which held, and added a charge, and got not cooling, but 
> it was too late to continue the diagnostics. I wanted to finish 
> charging tonight. The ambient temp is approx. 78 degrees, and my 
> static pressure was 80psi. I don't have a 66 service manual, so I 
> tried the numbers in the 65 manual. At approx. 2000 rpm, with the deck 
> lid closed, I get 20 on the low and 130 on the high. Bumping just a 
> few seconds of charge raised the numbers to 24/145. Output temp is at 
> 80 degrees, so nothing yet. If I increase the pressure to about 40/200 
> the clutch begins to squeal. I see what looks like white liquid, 
> fairly solid in the sight glass (could be bubbles?), but not sure 
> exactly what pressure I should see at this outside temp. I did find 
> the two seals on the condenser are missing, so I'll replace those 
> tomorrow, and the deck lid seal is good, but I'm sure there are 
> probably some small leaks around the engine seal - oh and the 
> summer/winter plate is missing. Other than the obvious things 
> mentioned - any ideas? I've been out of the R-12 world for way too 
> many years.
>
>
> Garry Parsley
>