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AC R134a Level

stushug

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Pittsburgh, PA
I have AC in my 68 Charger with a 440. When the car was restored in 2009, I had the "firewall forward" kit from Classic Auto Air installed. The morons that run the place now are impossible to deal with and offer what is possibly the worst customer service of any company I've ever dealt with. The AC is blowing warm air and the compressor is cycling frequently. That tells me that it's short on refrigerant. I called Classic twice and not one of the useless incompetents on their staff can tell me how much freon to add to my system. Right now I have about 12lbs on my low side manifold gauge. Anyone on here know what it should read when full? I know that overfilling can damage the compressor, so I want to avoid that.
I'm running a Sanden SD5H14 Model #S6664 compressor and it is a R134a system. Thanks, guys!
 
Start adding until it gets cold. There must be a leak somewhere. If it is cycling, it probably isn't too low. Start with 1 can, if its still warm, add another.
I would guess that it is hard to know the exact amount on a conversion.
 
I have AC in my 68 Charger with a 440. When the car was restored in 2009, I had the "firewall forward" kit from Classic Auto Air installed. The morons that run the place now are impossible to deal with and offer what is possibly the worst customer service of any company I've ever dealt with. The AC is blowing warm air and the compressor is cycling frequently. That tells me that it's short on refrigerant. I called Classic twice and not one of the useless incompetents on their staff can tell me how much freon to add to my system. Right now I have about 12lbs on my low side manifold gauge. Anyone on here know what it should read when full? I know that overfilling can damage the compressor, so I want to avoid that.
I'm running a Sanden SD5H14 Model #S6664 compressor and it is a R134a system. Thanks, guys!
Because no one can tell you that. All they can say is what the complete system took when it was new. That's why there are gauges for testing and filling as needed. You should have high and low pressure gauges and follow the guidelines in the manual.
 
Does the system have a sight glass in the receiver/dryer ?
If so you can use it to see the freon bubbles start to clear.Rule of thumb is allow a small amount of bubles in the sight glass for 134A
I would guess that it is hard to know the exact amount on a conversion.
R134A usually runs at about 250 to 300 psi on the high side.
You conversion has a cycling compressor clutch that cycles with low side readings.
Low side readings are read by temperatures as well as pressure. This also has to deal with the controls on the dash.
Set at the coldest max air you should see compressor clutch on around 50-70 degrees and off around 15 degrees.This is to keep the evaporator from freezing .
Also you have to consider barometric pressure and ambient temp while working in your area.This will also change the low/high readings.
I know clear as mud. Sight Glass clearing is the easiest way to judge on a conversion with a cycling compressor.
With the much smaller Sanden compressor, 2lbs should be enough max 2 1/2 lbs.The factory stock condenser is quite larger than most aftermarket condensers.
I just installed Vintage Air in my 63 using the old school hung under dash unit.
It took 1lbs to blow 19 degree air with a total of 1 1/2lbs complete.
 
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Because no one can tell you that. All they can say is what the complete system took when it was new. That's why there are gauges for testing and filling as needed. You should have high and low pressure gauges and follow the guidelines in the manual.
It's their kit, they should know what goes in it to make it work. That still doesn't excuse them for never calling back, never answering email, etc. When I first started dealing with them in 2001, I always dealt with a guy named Curtis. Always had the answers, always returned phone calls and always took care of my needs. Since he retired, I've had nothing but extremely piss poor service, horrible communication and a total lack of customer service. And that's with me spending a lot of money with them.
 
Does the system have a sight glass in the receiver/dryer ?
If so you can use it to see the freon bubbles start to clear.Rule of thumb is allow a small amount of bubles in the sight glass for 134A

R134A usually runs at about 250 to 300 psi on the high side.
You conversion has a cycling compressor clutch that cycles with low side readings.
Low side readings are read by temperatures as well as pressure. This also has to deal with the controls on the dash.
Set at the coldest max air you should see compressor clutch on around 50-70 degrees and off around 15 degrees.This is to keep the evaporator from freezing .
Also you have to consider barometric pressure and ambient temp while working in your area.This will also change the low/high readings.
I know clear as mud. Sight Glass clearing is the easiest way to judge on a conversion with a cycling compressor.
There isn't a sight glass, but I know what you're talking about because I just went through this on my '70 Cadillac. That's a whole different beast, because you have to have everything working perfectly since it has automatic climate control. You mentioned 250-300psi on the high side. My Cad runs about there, with about 34 on the low side. Can I assume the Charger would be close to those numbers?
 
It's their kit, they should know what goes in it to make it work. That still doesn't excuse them for never calling back, never answering email, etc. When I first started dealing with them in 2001, I always dealt with a guy named Curtis. Always had the answers, always returned phone calls and always took care of my needs. Since he retired, I've had nothing but extremely piss poor service, horrible communication and a total lack of customer service. And that's with me spending a lot of money with them.
For what it is worth I have never had an issue with them. Again all they can tell you is what refrigerant and how much a new install with their evaporator kit will take. Here is the instructions for the newest kit. A person versed on servicing A/C systems does not need to ask this question. People get hurt not knowing the pressures and what they should be. Half the people ask where is the low side and how do I fill it. For the most part most people should not attempt to work on these systems. Hook that can up on a malfunctioning system and see what might happen. Then its the guys fault that guessed on what it should take. What does your high pressure gauge say? https://www.classicautoair.com/wp-content/uploads/2021/01/1-2066-INSTALL-INSTRUCTIONS-06-29-21.pdf?
 
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Yes but does your 70 Cad have the stock compressor? If so it won't cycle on and off. I believe those had POA valves to control evaporator temps. The low side reading of 34 should be the temp coming out of the vents.
Close enough I'd say.
 
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There isn't a sight glass, but I know what you're talking about because I just went through this on my '70 Cadillac. That's a whole different beast, because you have to have everything working perfectly since it has automatic climate control. You mentioned 250-300psi on the high side. My Cad runs about there, with about 34 on the low side. Can I assume the Charger would be close to those numbers?
An A/C system function is the same from a Yugo to a Semi.
 
Yes but does your 70 Cad have the stock compressor? If so it won't cycle on and off. I believe those had POA valves to control evaporator temps. The low side reading of 34 should be the temp coming out of the vents.
Close enough I'd say.
Yes, it has the stock compressor, rebuilt by Classic. You're correct, it has a POA calibrated to 134a and the compressor does not cycle in that system.
 
For what it is worth I have never had an issue with them. Again all they can tell you is what refrigerant and how much a new install with their evaporator kit will take. Here is the instructions for the newest kit. A person versed on servicing A/C systems does not need to answer this question. People get hurt not knowing the pressures and what they should be. Halp the people ask where is the low side and how do I fill it. For the most part most people should not attempt to work on these systems. Hook that can up on a malfunctioning system and see what might happen. Then its the guys fault that guessed on what it should take. What does your high pressure gauge say? https://www.classicautoair.com/wp-content/uploads/2021/01/1-2066-INSTALL-INSTRUCTIONS-06-29-21.pdf?
Like I mentioned earlier, I've dealt with them since about 2001, and always directly with Curtis until he retired. He even warned me that when he was leaving that things would be going downhill. Perhaps that is part of the reason he left. While he was there, I had virtually 100% satisfaction. Since he left, I've had VERY little joy. They never return phone calls, rarely answer emails, horrible communication if at all, etc. All while I was spending a ton of money with them. I cringe to think how they treat customers with smaller projects. Sorry for the mini rant, but that's been my experience. Thanks for your insight into solving my current problem, though, I appreciate it.
 
Make sure the cooling fans are working properly (if you have an electric) Setting a box fan in front of the radiator can help. Add a little freon until the compressor quits cycling often and monitor the center duct temperature. Add a little more and let it stabilize as you watch the duct thermometer. I set the controls on full cold and low to medium fan speed. If all the components in the system are working properly, I can usually get low 40° to high 30° out of a 134 system.

Duct thermometer? I like a digital one. I find them more accurate than the old dial type You can use a non contact thermometer but remember, it measures surface temps and not air temp.
 
On a stock ac system that was retrofitted, the correct charge for 134a is 80% of the r12 amount. Since yours is a conversion we don’t know that amount. The correct way to charge is on the low side with vehicle running. I shoot for 33-35 on the low side with the rpm at 1000-1200 since that is cruising rpm. Low side pressure is relative to evaporator temp so you don’t want any lower that that because of freezing. High side will be 150-220ish depending on ambient temp and humidity but is not that important as long as it’s in that range.
 
As a temporary fix go to your local parts store and get a can of R134 with the built in gauge. Follow the instructions on the can and it will start cooling again. This a only a band aid ... you probably have a leak and need to find/repair that.
 
I have AC in my 68 Charger with a 440. When the car was restored in 2009, I had the "firewall forward" kit from Classic Auto Air installed. The morons that run the place now are impossible to deal with and offer what is possibly the worst customer service of any company I've ever dealt with. The AC is blowing warm air and the compressor is cycling frequently. That tells me that it's short on refrigerant. I called Classic twice and not one of the useless incompetents on their staff can tell me how much freon to add to my system. Right now I have about 12lbs on my low side manifold gauge. Anyone on here know what it should read when full? I know that overfilling can damage the compressor, so I want to avoid that.
I'm running a Sanden SD5H14 Model #S6664 compressor and it is a R134a system. Thanks, guys!
OK, if it is low there is no set amount to put in.
You need high readings also to see if there is a blockage.
If not blocked. Then do the following.

Add some dye to the system when you add freon. Also buy a leak detector Elitech WJL-6000S Freon Leak Detector Halogen Refrigerant Tester AC Leak Sniffer R22 R410A R134A R1234YF https://a.co/d/9N7tajV
You need a Guage set with high and low pressures.
The pressures are relative to ambient temperature and humidity.
My experience with r134a is low pressure between 22 and 30 psi especially with a rotary compressor.
The high range is the ambient times 2 to 2.2
The center vent should be below 50 degrees with a window open and the car at 1300 rpm.
R134a does not charge via site glass.
 
I will pick up the detector you mentioned. I think my other car has a leak, so that will help diagnose it. I do have a set of manifold gauges, but I have a problem with high readings. The fitting for the high side is right next to the distributor, and there is no way to attach it without removing the distributor. I'm not sure what the restoration shop did back in 2009 when they put the car together and charged the system initially. I'm going to have to research getting a new hose with the fitting clocked about 90 degrees from where it is now.



20230518_172247.jpg20230522_165354.jpg
 
OK, if it is low there is no set amount to put in.
You need high readings also to see if there is a blockage.
If not blocked. Then do the following.

Add some dye to the system when you add freon. Also buy a leak detector Elitech WJL-6000S Freon Leak Detector Halogen Refrigerant Tester AC Leak Sniffer R22 R410A R134A R1234YF https://a.co/d/9N7tajV
You need a Guage set with high and low pressures.
The pressures are relative to ambient temperature and humidity.
My experience with r134a is low pressure between 22 and 30 psi especially with a rotary compressor.
The high range is the ambient times 2 to 2.2
The center vent should be below 50 degrees with a window open and the car at 1300 rpm.
R134a does not charge via site glass.
I saw different dyes while looking at the sniffer. I assume I need a dye injector also. Can you recommend a dye and an injector?
 
I saw different dyes while looking at the sniffer. I assume I need a dye injector also. Can you recommend a dye and an injector?
Dye is universal InterDynamics Certified A/C Pro Car Air Conditioner Leak Detector Dye, Leak Detection UV Dye Detects Leaks in R-12 and R-134A Air Condition Systems, 1 Oz https://a.co/d/6640V2i
Injector SURIEEN AC Oil and Dye Injector Kit with Snap Quick Coupler, for R410A R134A R22 R12 Refrigerant System, 2 OZ Hand Turn Screw-in Type HVAC Dye Oil Injector with 1/4" SAE Connector https://a.co/d/f4H2pTP

Or go to your parts store and get
Johnsen's 6313 R134a Refrigerant w/UV Dye for MVAC use in a 12oz Self-Sealing Container (3 Pack) (3) https://a.co/d/7K8uxEV
You only need 1 and it will never go away

Right angle adapter R12 to R134 A High/Low AC Fitting Port Retrofit Conversion Adapter, Quick Coupler Valve A/C 90° Fitting, High and Low Side R-12 to R-134A Retrofit with 2PC Caps https://a.co/d/1cgCYlr
Or if a your connector is too big maybe
Lichamp A/C R134A Adapters with Puncture 134A Can Tap, AC 134 Quick Coupler Hose Connector Fitting Kit with Tank Adapter and Valve Core Remover, QA02 https://a.co/d/4UAf8DO
Or see if you can rotate the hose when the system is discharged
 
Thanks for the info! I don't think any of the adapters will work, both the low and high side hoses already have the quick connect fittings. My gauges have the correct connectors, the problem is the high side valve is so close to the distributor, there's no room to put the connector onto the hose fitting. It may be difficult to see in the pics I uploaded, but there's no way to put the high side connector on while the distributor is in place.


high side.jpg
 
about 50

There's a chart based on heat in your location at the time you take the reading. Should be relatively easy to find on line.

...but it's somewhere around 50 on the low side.
 
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