absolutely the best in depth easy to follow and understand old school late 60s early 70s chevy a body ac video ever, must watch twice to absorb it all.😊
I don't think I can do another summer in my 68 cutlass without AC. Great info! Edit: This is a fantastic, well put together informative video. Subscribed!
i am a 40 yr GM tech, have to say, you are A1 spot on with this info. You would be top a/c instructor at any of the GM training centers . . . {if they still existed today} . . . Thanks, from an old ASE Master Tech . . .lol! ;)
That's quite a complement thank you! Would love to learn a few things from what you saw over 40yrs. I imagine you must have survived some of these systems?
Solid content, excellent job explaining GM’s early AC. The only item that I give any complaints would be the sight glass…I believe it’s useless with 134 but was very useful with R12. I restore GM cars/trucks…if customer insists on using original AC equipment…I insist on using R12 at whatever cost.
Awesome video and explanation. I Started pulling all the wiring from my 70 suitcase last week. It’s missing a lot of the under hood equipment and the bottom of the evaporator case is rotted out. Can appreciate the fact you’ve chosen to keep yours. If you need any under dash components let me know.
Thanks Roddy. I'll keep that in mind. I'll be going through the cables and vacuum control valve in the next few months to get those moving more smoothly
Magnificent your contribution is ! 73 nova 350 4dr all original w ac 76,667 miles out of police impound 2 MO ths ago 3 1 22. AZ car now in socal. Had to pull heater box case to locate body numbers at firewall under blower motor to show CHP to complete DMV transfer. It's 90 % off. I have access to the numbers and transfer is complete. Watching your video really helped me make some decisions. As I'm low budget and lack alot of classic car experience. Mainly I was wondering how much and how in depth to restore the ac system since it's already nearly off. I'm just stating my journey. I was wondering how much to restore and or paint the firewall as well since the suitcase will Be off. you answered what parts should be kept and which ones should be replaced and which one should be adjusted. Interestingly most other videos replace the evaporator. I might try keeping mine since I'm all original if there's no issues with it. I'm wondering now if once the evaporator is out can it be refurbished? So much appreciated for you info .......
Thank you Rod! Was a pleasure putting this together and sharing what I've learned. I'm sure I don't have everything right but definitely with to be dangerous 👍
@@thebandit4393 I have a question, too. I have a 73 Nova in which the condenser was replaced last week with a horizontal type after a leak test showed the old condenser leaked. Now when the AC runs a long time the POA valve freezes up. If I turn off the compressor and leave the fan on it unfreezes and AC blows cold again. Seems like moisture in the system if so why? Maybe the expansion valve, receiver/dryer unit, just didn't flush out all of the moisture before charging or anything else? A little history: It was converted to 134a in the past. When the condenser was replaced, he did not replace the dryer/receiver unit. I asked him why and he stated that it was replaced in the past and the system was not open. I guessed he capped the lines from condenser??? The AC runs better then ever but in the past I wasn't observant enough to see if the POA valve was freezing. Thanks
@@RowdyCStuff What do you mean when you say the POA freezes? It's normal for frost/ice to form on the outside, downstream side of the POA valve and the lines going to the compressor. This happens because there is a pressure drop through the POA and the downstream refrigerant temperature gets even colder than the evaporator temperature. If your evaporator is freezing up it's possible the POA valve is not regulating properly. It could be adjusted to a lower pressure than needed, it could be stuck slightly open (due to debris for example), or it could have an internal leak. I would check the evaporator pressure at the POA valve while the system is running with the blower on low speed. This will allow the compressor to pull the evaporator down to the POA set point and you can see what pressure its regulating to.
Your running continuous compressor "on" . Would help txv regulation if u wrapped txv in cork or tacky tape . Reduce txv from engine bay heat . Shorter txv equalisation tube and sensing bulb lines . Is there an idle "up" facility or target idle with a/c on =generally 100-200 higher rpm . Good job and glad to see another GM factory air surviving . World wide GM air is 90% similar
I like that idea and it's easy enough to do. The long sensing lines are unfortunately due to the lack of available replacements with the proper length.
Ceramic coat headers keeps the heat down also [cannot see in vid] . Engine bay fibre glass evap boxes suffer from poor insulation typical GM . I used sticky f/glass insulation with a foil face to cover the box .
I do have ceramic coated headers but a heat barrier like DEI Firewall and Tunnel Shield would be a great addition. The trick is there just isn't much space between the AC suitcase and the engine for that on my car.
If it's prior to VIR, it should be basically the same setup. I highly recommend the model-specific factory service manual - it has a lot of great info on how the system operates and troubleshooting steps. Good luck!
I'm piecing together an AC system. My 68 firebird was a factory AC car. Seems weird that the compressor and heat are on at the same time if you want the heat to come out of the dash vents. I might just put in a switch to make sure the AC compressor won't turn on when I don't want it
I think that's a great idea. I have been thinking about divorcing the AC switch from the rest of these controls like they did in the 80s. I'd also like to divorce the recirculation function.
Great video-could you talk about the vacuum control heater valve you used? My understanding (very little)is the OEM setup (in a early C3 corvette) has the heat controlled by the box flaps only. Thanks again.
I used a bypass style heater valve, Four Seasons 74781 / Everco 5930. This valve normally allows coolant flow to the heater core, but under vacuum it returns the coolant flow back to the waterpump without passing it through the heater core.
I noticed that you have a heater control valve plumbed into your heater hoses... It looks like a late GMT400 valve, is that correct? Also, what vacuum source are you using to actuate the valve?
The heater bypass valve is a Four Seasons 74781 / Everco 5930. It's controlled by the same vacuum control valve on the interior AC controls as the original heater shut off valve so the heater core is bypassed in the vent or max AC positions. I can't recall what application the valve was originally intended for
@@thebandit4393 Thank you for the info! I'm finally getting around to repairing the A/C in my '72 Ventura II and that would be a great "while I'm there" upgrade. Your Nova looks great, thanks for sharing it with us! 🙂👍
Where did you get the j shaped fitting coming off poa valve to make new line to compressor? And what size is it? I have a 70 Monte Carlo and trying to get new lines made for my ac compressor on my ls6
The POA valve has a #12 o ring outlet. I used an Original Auto Air aka Classic Auto Air PN G13-407 Shepard's hook which takes it down to #10 barrier hose. Another option I tried that did not fit well was Nostalgic Auto Air PN G135. See post #1565 and #1579 of this thread for info and photos ls1tech.com/forums/conversions-swaps/1329686-70-nova-ly6-th400-6-0vvt.html
Hello, excellent tutorial. Could you give me the dimension (length and width) of the hole for the central air vents. It would be to fix a 1 din car radio in it instead. Greetings
@@limitlessautomedia9794 Yes their system is completely under dash. I think if you want factory AC and twin turbos you will have to get very very creative with packaging. It's hard enough to package a twin turbo setup as it is. I'm not going to say it's impossible though. You just might have to route exhaust on the outside of the frame or something similarly out of the box
I have a 74 nova hatchback with the original ac as well. I just recently swap in a 5.3 ls but the box wouldn't clear. It hits the valve cover and headers. How did you clear yours? Thanks Minh
I made a small notches in the box to clear the passenger cylinder head and used fiberglass to create a pocket in that area. It is really going to depend on where your engine is mounted exactly and what headers you're using. In my case I'm using Doug's Headers SK100 mounts in the 1/2" setback position along with their headers. There are photos of notching the box in my build thread on Ls1tech.com. Search for LY6/TH400 Nova thread by TheBandit.
@@minhdang8165 Happy to help. One other point - your '74 is a valve in receiver aka "VIR" system. It has a POA valve integrated into it that is non adjustable. If you are converting to R134a I think your best option is a VIR eliminator.
Yes. I bought the drier from Vintage Air but it's just a universal type. They usually have a port on them for installing a binary or trinary switch. I recommend installing a trinary switch for electric fan control.
Excellent video! I'm about to restore mine in my 72 Nova. As you well know, I did the LS swap like you. I need to pick up a compressor, and in the video you mentioned the Denzo 10S17, correct? From a junkyard maybe or new? How were you able to match up the hoses? Did you make them yourself, or can these be bought plug-n-play? Thanks for any help you can provide!
I can give you a more detailed run down. If you are in Instagram please message me there. I'm @chevyhotrodder. I notched my subframe to fit the Denso compressor down low. It's the OE compressor on most pickups with Gen III and IV LS engines. I used adapters from Docs Blocs (no longer in business but there are other companies that should have them) to get to standard o ring SAE fittings. I used a Vintage Air condenser but honestly it's just a universal parallel flow type and I ended up not using their mounts or hardlines because I didn't like their fitment. The hoses I crimped myself with a borrowed Mastercool crimper. You can buy barrier hose and crimp fittings a bunch of places. The only special fitting is the "Shepard's hook" on the POA valve which goes from the giant #12 outlet to a #10 hose. I will dig for the PN. You also need a new TX valve and to recalibrate your POA I have a couple other videos on flushing the system and recalibrating. I recommend a trinary switch for fan control. I can video chat or call if it helps. Just ping me over Instagram.
@@thebandit4393 Wow, thank you sooooo much! Very nice detail! Yes I watched your other videos on flushing as well as the POA valve adjustment. Very informative! I'll be ready to start working on this in a few weeks so when I get some parts pulled together I'll ping you on Instagram. I think I have to replace the dryer, condenser and get the compressor of course. Once I have those in hand I'll contact you. I think the most difficulty I'll have will be making up the hoses. Thank you so much!!!
@@stevesgarage7644 No problem. Yes you'll need all those things. You'll also need some PAG oil. I used the truck application amount - hard to say what's needed exactly. Make sure you also flush the POA (I did it off the car into a bucket). I had a friend charge it and he estimated the needed amount watching the sight glass and pressures. I hope you have an adjustable POA - some are fixed. The only problem I have with my system is the vacuum control valve is finicky. Sometimes I get recirc when I expect it and sometimes not. I suspect the control valve needs to be replaced but I don't know if any are available aftermarket, so I may try rebuilding when I take it out next. I saw your video on fixing the control levers. It also helps to relube all the cables and the pivots for the duct flaps. The system works really well if everything is in repair. Good luck and feel free to reach out with and questions.
@@thebandit4393 Thank you! I'm a newbie when it comes to A/C systems but I'm not afraid to dive in. Already checking out a set of gauges and vacuum pump. The system has been open a while so the POA might be junk. Not sure yet.
@@stevesgarage7644 I'm a newbie too. This is the only system I've worked on but I did research it thoroughly and I have a mechanical engineering degree. We learned about refrigeration cycles in school but nothing beats real world experience. For what it's worth my POA was disconnected for 20years and seems to be working just fine. There are some details I didn't mention in the video. For example you'll find a small tube running from the bottom of the evaporator to the POA valve. That's an oil bleed designed to let a small amount of the liquid refrigerant to carry oil to the POA when the system is operating with little circulation (POA closed). There is a small o ring there that also should be replaced but it's not a standard size. I think I was able to order one from classic auto air in Florida.
I suggest you visit Steve's Nova Site. In the forum for Best of Electrical there is a thread with links to all the available wiring diagrams for each year
I'm curious my original expansion valve only has one copper coil coming out the top and the new one has two. One with the sensor on top and another with a nut coming out the back to attach somewhere. I noticed in the video that yours has two as well but I could not see where the copper line coming out the back connects to. Any help would be appreciated. to. Any help would be appreciated.=
One is connected to the evaporator outlet sensing bulb. The other is an equilizing line to measure the evaporator pressure which connects to a port on the POA. Between the evaporator pressure and the outlet temperature, the TXV knows the superheat and can allow more or less refrigerant through to achieve the desired superheat. Some TXVs have internal equilizing so they measure the evaporator pressure at the outlet of the TXV rather than remote.
That is a safety hi/lol switch which prevents the clutch from engaging if the pressures get too high or if there is a leak and the pressure is too low. I wired it inline with the compressor clutch. It will not cycle the clutch during normal operation. The only time it had any effect was before charging the system when the clutch would not run until some refrigerant was charged into the system.
@@ricardoparra6927 Yes this is referred to as a binary switch. It allows current to flow when the pressure is an an acceptable range. In this case the wire that supplies 12v for the compressor clutch routes from the interior controls to this binary switch, then from this switch to the clutch. Another type of switch is a trinary switch which can be used to control an electric fan.
@@thebandit4393 I truly appreciate the information. I am attempting to do what you've done on a 70 C10 with factory air. I have most components except this switch and how it's wired. Does the other wire go to the switch behind the selector box in the cab, known as the compressor switch operated by a diverter cable?
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Why can't they make it like a maverik beer cooler? AC in cars is not good enough unless you drive for along time!
Unfortunately the size of a car means there is a lot of surface area for heat to come through, not to mention all the windows and doors that are difficult to seal completely. You can however make a big improvement with insulation, especially on the firewall, tunnel, and floor where the engine heat tends to bake the interior. These olds cars aren't engineered to be sealed up or insulated like new cars - plenty can be done 👍
I spliced the hi/lo binary switch into the compressor clutch wire so it prevents clutch engagement if the high side pressure is too high or low. I installed mine into the drier but anywhere on the high pressure side of the system will work.
@TheBandit thanks. So, does this switch work as an interrupter and does the input come from the a/c control switch in the cab and does the output go directly to the clutch?
@@ricardoparra6927 Yes it is an interruptor. The wiring for the AC clutch runs from the firewall pass through behind the passenger cylinder head to the ambient freeze switch on the passenger side of the evaporator box then to the compressor clutch. I wired my binary switch between the ambient freeze switch and the compressor clutch.
@@ricardoparra6927 The ambient switch is used to prevent AC operation in freezing conditions. The only time it would normally come into play is if you are using the defroster while it's snowy cold outside. I would suggest installing a trinary switch if you want it to also control electric fans in the future. Better to install now rather to have to recharge the system later if you decide to swap one in.
@@davidtindall6427 The high bolsters are great for autocross. Even with just retractable 3pt belts, I don't have issues sliding side to side (harnesses would really help during hard braking). I did have to modify the Pro Car brackets to lower the seats by about 1" which helped driver position tremendously for me at 6'0" tall. The overall dimensions of the seat are better suited for someone shorter since the lumbar support is a little low for me, the top of the seat is a few inches below my shoulders, and I have to raise the headrest all the way up to position it behind my head. The width of the seat is good for me. I have a 36" waist If you're much larger you might consider the "wide" version of the seat.
absolutely the best in depth easy to follow and understand old school late 60s early 70s chevy a body ac video ever, must watch twice to absorb it all.😊
Thank you for the kind words!
I have a 1972 Pontiac GTO with factory AC. It blows very cold and still has R12 refrigerant.
I don't think I can do another summer in my 68 cutlass without AC. Great info! Edit: This is a fantastic, well put together informative video. Subscribed!
Thank you!
i am a 40 yr GM tech, have to say, you are A1 spot on with this info. You would be top a/c instructor at any of the GM training centers . . . {if they still existed today} . . . Thanks, from an old ASE Master Tech . . .lol! ;)
That's quite a complement thank you! Would love to learn a few things from what you saw over 40yrs. I imagine you must have survived some of these systems?
This is Golden
Solid content, excellent job explaining GM’s early AC. The only item that I give any complaints would be the sight glass…I believe it’s useless with 134 but was very useful with R12. I restore GM cars/trucks…if customer insists on using original AC equipment…I insist on using R12 at whatever cost.
R134a works at its best when system is 98% or greater full
Awesome video and explanation. I Started pulling all the wiring from my 70 suitcase last week. It’s missing a lot of the under hood equipment and the bottom of the evaporator case is rotted out. Can appreciate the fact you’ve chosen to keep yours. If you need any under dash components let me know.
Thanks Roddy. I'll keep that in mind. I'll be going through the cables and vacuum control valve in the next few months to get those moving more smoothly
Great Video ...Thanks
Magnificent your contribution is !
73 nova 350 4dr all original w ac
76,667 miles out of police impound 2 MO ths ago 3 1 22. AZ car now in socal. Had to pull heater box case to locate body numbers at firewall under blower motor to show CHP to complete DMV transfer. It's 90 % off. I have access to the numbers and transfer is complete. Watching your video really helped me make some decisions. As I'm low budget and lack alot of classic car experience. Mainly I was wondering how much and how in depth to restore the ac system since it's already nearly off. I'm just stating my journey. I was wondering how much to restore and or paint the firewall as well since the suitcase will Be off. you answered what parts should be kept and which ones should be replaced and which one should be adjusted. Interestingly most other videos replace the evaporator. I might try keeping mine since I'm all original if there's no issues with it. I'm wondering now if once the evaporator is out can it be refurbished? So much appreciated for you info .......
I see no reason to replace the evaporator if it still holds pressure. I would just flush it (as shown in one of my other videos).
GREAT GREAT GREAT video!!! I've watched it several times and learn something new each time.
Thank you Rod! Was a pleasure putting this together and sharing what I've learned. I'm sure I don't have everything right but definitely with to be dangerous 👍
@@thebandit4393 I have a question, too. I have a 73 Nova in which the condenser was replaced last week with a horizontal type after a leak test showed the old condenser leaked. Now when the AC runs a long time the POA valve freezes up. If I turn off the compressor and leave the fan on it unfreezes and AC blows cold again. Seems like moisture in the system if so why? Maybe the expansion valve, receiver/dryer unit, just didn't flush out all of the moisture before charging or anything else? A little history: It was converted to 134a in the past. When the condenser was replaced, he did not replace the dryer/receiver unit. I asked him why and he stated that it was replaced in the past and the system was not open. I guessed he capped the lines from condenser??? The AC runs better then ever but in the past I wasn't observant enough to see if the POA valve was freezing. Thanks
@@RowdyCStuff What do you mean when you say the POA freezes? It's normal for frost/ice to form on the outside, downstream side of the POA valve and the lines going to the compressor. This happens because there is a pressure drop through the POA and the downstream refrigerant temperature gets even colder than the evaporator temperature.
If your evaporator is freezing up it's possible the POA valve is not regulating properly. It could be adjusted to a lower pressure than needed, it could be stuck slightly open (due to debris for example), or it could have an internal leak. I would check the evaporator pressure at the POA valve while the system is running with the blower on low speed. This will allow the compressor to pull the evaporator down to the POA set point and you can see what pressure its regulating to.
Your running continuous compressor "on" . Would help txv regulation if u wrapped txv in cork or tacky tape . Reduce txv from engine bay heat . Shorter txv equalisation tube and sensing bulb lines .
Is there an idle "up" facility or target idle with a/c on =generally 100-200 higher rpm .
Good job and glad to see another GM factory air surviving . World wide GM air is 90% similar
I like that idea and it's easy enough to do. The long sensing lines are unfortunately due to the lack of available replacements with the proper length.
Ceramic coat headers keeps the heat down also [cannot see in vid] .
Engine bay fibre glass evap boxes suffer from poor insulation typical GM . I used sticky f/glass insulation with a foil face to cover the box .
I do have ceramic coated headers but a heat barrier like DEI Firewall and Tunnel Shield would be a great addition. The trick is there just isn't much space between the AC suitcase and the engine for that on my car.
excellent tutorial.
Thank you! Hope it was helful
That was very helpful! I am upgrading a 1972 Buick Gran Sport and this has similarities.
If it's prior to VIR, it should be basically the same setup. I highly recommend the model-specific factory service manual - it has a lot of great info on how the system operates and troubleshooting steps. Good luck!
Great video bud, thanks for all the helpful info!
You're welcome!
I'm piecing together an AC system. My 68 firebird was a factory AC car. Seems weird that the compressor and heat are on at the same time if you want the heat to come out of the dash vents. I might just put in a switch to make sure the AC compressor won't turn on when I don't want it
I think that's a great idea. I have been thinking about divorcing the AC switch from the rest of these controls like they did in the 80s. I'd also like to divorce the recirculation function.
Very well presented young man. You make me think maybe you have a background as a mechanical engineer???? I am going watch your POA video next.
Thank you! Yes I am a mechanical engineer, but I don't specialize in thermodynamics or HVAC - just learned some of the fundamentals.
Great video-could you talk about the vacuum control heater valve you used?
My understanding (very little)is the OEM setup (in a early C3 corvette) has the heat controlled by the box flaps only.
Thanks again.
I used a bypass style heater valve, Four Seasons 74781 / Everco 5930. This valve normally allows coolant flow to the heater core, but under vacuum it returns the coolant flow back to the waterpump without passing it through the heater core.
I noticed that you have a heater control valve plumbed into your heater hoses... It looks like a late GMT400 valve, is that correct? Also, what vacuum source are you using to actuate the valve?
The heater bypass valve is a Four Seasons 74781 / Everco 5930. It's controlled by the same vacuum control valve on the interior AC controls as the original heater shut off valve so the heater core is bypassed in the vent or max AC positions. I can't recall what application the valve was originally intended for
@@thebandit4393 Thank you for the info! I'm finally getting around to repairing the A/C in my '72 Ventura II and that would be a great "while I'm there" upgrade.
Your Nova looks great, thanks for sharing it with us! 🙂👍
@@michaeldavis3430 Thank you! Feel free to ask any questions you have. You can also find me on Instagram at @chevyhotrodder
Where did you get the j shaped fitting coming off poa valve to make new line to compressor? And what size is it? I have a 70 Monte Carlo and trying to get new lines made for my ac compressor on my ls6
The POA valve has a #12 o ring outlet. I used an Original Auto Air aka Classic Auto Air PN G13-407 Shepard's hook which takes it down to #10 barrier hose. Another option I tried that did not fit well was Nostalgic Auto Air PN G135. See post #1565 and #1579 of this thread for info and photos ls1tech.com/forums/conversions-swaps/1329686-70-nova-ly6-th400-6-0vvt.html
Hello, excellent tutorial.
Could you give me the dimension (length and width) of the hole for the central air vents. It would be to fix a 1 din car radio in it instead.
Greetings
This is great info for a LS swap ac system but what about a twin turbo set up.
Twin turbo and factory AC would be a lot to package. I can't help you there sorry
@@thebandit4393 I believe vintage air has there kit under the dash. It would save space but not money.
@@limitlessautomedia9794 Yes their system is completely under dash. I think if you want factory AC and twin turbos you will have to get very very creative with packaging. It's hard enough to package a twin turbo setup as it is. I'm not going to say it's impossible though. You just might have to route exhaust on the outside of the frame or something similarly out of the box
I have a 74 nova hatchback with the original ac as well. I just recently swap in a 5.3 ls but the box wouldn't clear. It hits the valve cover and headers. How did you clear yours? Thanks Minh
I made a small notches in the box to clear the passenger cylinder head and used fiberglass to create a pocket in that area. It is really going to depend on where your engine is mounted exactly and what headers you're using. In my case I'm using Doug's Headers SK100 mounts in the 1/2" setback position along with their headers. There are photos of notching the box in my build thread on Ls1tech.com. Search for LY6/TH400 Nova thread by TheBandit.
Thank you so much. Will definitely read thread.
@@minhdang8165 Happy to help. One other point - your '74 is a valve in receiver aka "VIR" system. It has a POA valve integrated into it that is non adjustable. If you are converting to R134a I think your best option is a VIR eliminator.
I'm gonna order a vir eliminator
Did your drier already have an port for the binary switch?
Yes. I bought the drier from Vintage Air but it's just a universal type. They usually have a port on them for installing a binary or trinary switch. I recommend installing a trinary switch for electric fan control.
Excellent video! I'm about to restore mine in my 72 Nova. As you well know, I did the LS swap like you. I need to pick up a compressor, and in the video you mentioned the Denzo 10S17, correct? From a junkyard maybe or new? How were you able to match up the hoses? Did you make them yourself, or can these be bought plug-n-play? Thanks for any help you can provide!
I can give you a more detailed run down. If you are in Instagram please message me there. I'm @chevyhotrodder. I notched my subframe to fit the Denso compressor down low. It's the OE compressor on most pickups with Gen III and IV LS engines. I used adapters from Docs Blocs (no longer in business but there are other companies that should have them) to get to standard o ring SAE fittings. I used a Vintage Air condenser but honestly it's just a universal parallel flow type and I ended up not using their mounts or hardlines because I didn't like their fitment. The hoses I crimped myself with a borrowed Mastercool crimper. You can buy barrier hose and crimp fittings a bunch of places. The only special fitting is the "Shepard's hook" on the POA valve which goes from the giant #12 outlet to a #10 hose. I will dig for the PN. You also need a new TX valve and to recalibrate your POA I have a couple other videos on flushing the system and recalibrating. I recommend a trinary switch for fan control. I can video chat or call if it helps. Just ping me over Instagram.
@@thebandit4393 Wow, thank you sooooo much! Very nice detail! Yes I watched your other videos on flushing as well as the POA valve adjustment. Very informative! I'll be ready to start working on this in a few weeks so when I get some parts pulled together I'll ping you on Instagram. I think I have to replace the dryer, condenser and get the compressor of course. Once I have those in hand I'll contact you. I think the most difficulty I'll have will be making up the hoses. Thank you so much!!!
@@stevesgarage7644 No problem. Yes you'll need all those things. You'll also need some PAG oil. I used the truck application amount - hard to say what's needed exactly. Make sure you also flush the POA (I did it off the car into a bucket). I had a friend charge it and he estimated the needed amount watching the sight glass and pressures. I hope you have an adjustable POA - some are fixed. The only problem I have with my system is the vacuum control valve is finicky. Sometimes I get recirc when I expect it and sometimes not. I suspect the control valve needs to be replaced but I don't know if any are available aftermarket, so I may try rebuilding when I take it out next. I saw your video on fixing the control levers. It also helps to relube all the cables and the pivots for the duct flaps. The system works really well if everything is in repair. Good luck and feel free to reach out with and questions.
@@thebandit4393 Thank you! I'm a newbie when it comes to A/C systems but I'm not afraid to dive in. Already checking out a set of gauges and vacuum pump. The system has been open a while so the POA might be junk. Not sure yet.
@@stevesgarage7644 I'm a newbie too. This is the only system I've worked on but I did research it thoroughly and I have a mechanical engineering degree. We learned about refrigeration cycles in school but nothing beats real world experience. For what it's worth my POA was disconnected for 20years and seems to be working just fine. There are some details I didn't mention in the video. For example you'll find a small tube running from the bottom of the evaporator to the POA valve. That's an oil bleed designed to let a small amount of the liquid refrigerant to carry oil to the POA when the system is operating with little circulation (POA closed). There is a small o ring there that also should be replaced but it's not a standard size. I think I was able to order one from classic auto air in Florida.
Good morning im working on my ac on my 72 nova, do you have like a diagram for the wiring
I suggest you visit Steve's Nova Site. In the forum for Best of Electrical there is a thread with links to all the available wiring diagrams for each year
I'm curious my original expansion valve only has one copper coil coming out the top and the new one has two. One with the sensor on top and another with a nut coming out the back to attach somewhere. I noticed in the video that yours has two as well but I could not see where the copper line coming out the back connects to. Any help would be appreciated.
to. Any help would be appreciated.=
One is connected to the evaporator outlet sensing bulb. The other is an equilizing line to measure the evaporator pressure which connects to a port on the POA. Between the evaporator pressure and the outlet temperature, the TXV knows the superheat and can allow more or less refrigerant through to achieve the desired superheat. Some TXVs have internal equilizing so they measure the evaporator pressure at the outlet of the TXV rather than remote.
Great vid! Thank you. How did you wire your cycling switch on the dryer?
That is a safety hi/lol switch which prevents the clutch from engaging if the pressures get too high or if there is a leak and the pressure is too low. I wired it inline with the compressor clutch. It will not cycle the clutch during normal operation. The only time it had any effect was before charging the system when the clutch would not run until some refrigerant was charged into the system.
@@thebandit4393 Thank you kindly.
@@thebandit4393 Is it the same as a binary switch? One wire goes to the compressor clutch and the other to ground or somewhere else?
@@ricardoparra6927 Yes this is referred to as a binary switch. It allows current to flow when the pressure is an an acceptable range. In this case the wire that supplies 12v for the compressor clutch routes from the interior controls to this binary switch, then from this switch to the clutch. Another type of switch is a trinary switch which can be used to control an electric fan.
@@thebandit4393 I truly appreciate the information. I am attempting to do what you've done on a 70 C10 with factory air. I have most components except this switch and how it's wired. Does the other wire go to the switch behind the selector box in the cab, known as the compressor switch operated by a diverter cable?
Why can't they make it like a maverik beer cooler? AC in cars is not good enough unless you drive for along time!
Unfortunately the size of a car means there is a lot of surface area for heat to come through, not to mention all the windows and doors that are difficult to seal completely. You can however make a big improvement with insulation, especially on the firewall, tunnel, and floor where the engine heat tends to bake the interior. These olds cars aren't engineered to be sealed up or insulated like new cars - plenty can be done 👍
How is your hi-low switch wired?
I spliced the hi/lo binary switch into the compressor clutch wire so it prevents clutch engagement if the high side pressure is too high or low. I installed mine into the drier but anywhere on the high pressure side of the system will work.
@TheBandit thanks. So, does this switch work as an interrupter and does the input come from the a/c control switch in the cab and does the output go directly to the clutch?
@@ricardoparra6927 Yes it is an interruptor. The wiring for the AC clutch runs from the firewall pass through behind the passenger cylinder head to the ambient freeze switch on the passenger side of the evaporator box then to the compressor clutch. I wired my binary switch between the ambient freeze switch and the compressor clutch.
@@thebandit4393 I appreciate you. My setup is slightly different (70 C10) without the ambient sensor but it may not be necessary. Thank you.
@@ricardoparra6927 The ambient switch is used to prevent AC operation in freezing conditions. The only time it would normally come into play is if you are using the defroster while it's snowy cold outside. I would suggest installing a trinary switch if you want it to also control electric fans in the future. Better to install now rather to have to recharge the system later if you decide to swap one in.
What front buckets are those?
Pro Car Rally Houndstooth
@@thebandit4393 they hold you in place pretty well at autox?
@@davidtindall6427 The high bolsters are great for autocross. Even with just retractable 3pt belts, I don't have issues sliding side to side (harnesses would really help during hard braking). I did have to modify the Pro Car brackets to lower the seats by about 1" which helped driver position tremendously for me at 6'0" tall. The overall dimensions of the seat are better suited for someone shorter since the lumbar support is a little low for me, the top of the seat is a few inches below my shoulders, and I have to raise the headrest all the way up to position it behind my head. The width of the seat is good for me. I have a 36" waist If you're much larger you might consider the "wide" version of the seat.