A/C Question regarding different years

[Branktm]

I have a 76 K15 Sierra Grande that came with factory air. I have a fresh SBC 383 stroker in it but I added a serpentine belt system from a 92. meaning it runs counter clockwise. Had to change fans, alter the alternator etc. The belt system still has the 92 compressor on it, im sure its junk. I need to complete my A/C heat and then this build is Finally done after 3 years. Am I thinking too much about this, can i just by the compressor for the 92, get a new condenser, and then everything will plug and play? What am I missing? Thanks in advance.

 

[fast 99]

Picture of belt system? As far as I know, the only component that runs reverse direction is water pump, tensioner and or idler pully. Easy to tell, will not have grooved pully.

 

[Bextreme04]

I have a 76 K15 Sierra Grande that came with factory air. I have a fresh SBC 383 stroker in it but I added a serpentine belt system from a 92. meaning it runs counter clockwise. Had to change fans, alter the alternator etc. The belt system still has the 92 compressor on it, im sure its junk. I need to complete my A/C heat and then this build is Finally done after 3 years. Am I thinking too much about this, can i just by the compressor for the 92, get a new condenser, and then everything will plug and play? What am I missing? Thanks in advance.

The only thing that runs counter-clockwise should be the water pump pulley, due to how it is looped over the water pump pulley. Everything else should still be spinning in the same clockwise direction it always has.

Personally, I would just run the compressor you have. Your biggest issue is going to be finding hoses to go from the 92 compressor to the condensor and the filter/dryer. I would flush everything well with AC flush, replace all O-rings with modern R134 compliant ones, put in a blue orifice tube, replace the filter/dryer, replace the compressor safety switch with one designed for R134 pressures, and then vacuum the system for AT LEAST an hour to make sure you get all of the moisture out. Then charge it and you should be good to go. My 1980 K25 with all original compressor, condensor, evaporator, with the R134 switch and blue orifice blows 38 degree air out the vents on 95 degree ambient air days.

 

[Radiohead]

The only thing that runs counter-clockwise should be the water pump pulley, due to how it is looped over the water pump pulley. Everything else should still be spinning in the same clockwise direction it always has.

Personally, I would just run the compressor you have. Your biggest issue is going to be finding hoses to go from the 92 compressor to the condensor and the filter/dryer. I would flush everything well with AC flush, replace all O-rings with modern R134 compliant ones, put in a blue orifice tube, replace the filter/dryer, replace the compressor safety switch with one designed for R134 pressures, and then vacuum the system for AT LEAST an hour to make sure you get all of the moisture out. Then charge it and you should be good to go. My 1980 K25 with all original compressor, condensor, evaporator, with the R134 switch and blue orifice blows 38 degree air out the vents on 95 degree ambient air days.

You washed the entire system out prior, right? Or did you use new old stock or similar?
I ask because I would like to run the original stuff in the '79 and have heard that if you clean it real well and use r-134 specific things like the pressure switch. True or not in your experience?

 

[fast 99]

You washed the entire system out prior, right? Or did you use new old stock or similar?
I ask because I would like to run the original stuff in the '79 and have heard that if you clean it real well and use r-134 specific things like the pressure switch. True or not in your experience?

R12 systems can be converted to 134. There is probably a kit made. Yes it will need to be flushed and appropriate orifice tube and oil installed. 134a is a smaller molecule and does require o ring replacement. If possible and available buy replacement hoses using barrier material. Original hoses are likely past their due date anyway.

 

[Branktm]

Picture of belt system? As far as I know, the only component that runs reverse direction is water pump, tensioner and or idler pully. Easy to tell, will not have grooved pully.

I had to change fans because the stock one ran clockwise and didnt push air, but now a counterclockwise fan is operating correctly. I am actually put a clutch on the fan this weekend cause its still running hotter than id like in this summer heat

Anyways here are some pictures
Picture 1 and 2 are current pictures with fan shroud removed
Picture 3 is belt system on the 92 SBC i took the system off of
Picture 4 is early in the build for better visibility

 

[Branktm]

You washed the entire system out prior, right? Or did you use new old stock or similar?
I ask because I would like to run the original stuff in the '79 and have heard that if you clean it real well and use r-134 specific things like the pressure switch. True or not in your experience?

Got truck with engine completely missing, so haven't touched anything on the heat and A/C side until right now after truck is drivable. Got a new heater core in today because when all the lines were hooked up, it shot coolant through and leaked and stained my just installed carpet. oopsie on my part for not testing first

 

[Bextreme04]

You washed the entire system out prior, right? Or did you use new old stock or similar?
I ask because I would like to run the original stuff in the '79 and have heard that if you clean it real well and use r-134 specific things like the pressure switch. True or not in your experience?

Yep, AC flush with solvent and compressed air. Did the evaporator and condenser individually. New manifold and lines(they are a single assembly for the A6) from the compressor to the condenser and from filter/dryer to compressor. New orifice tube(blue) and all new o-rings everywhere. New R134 pressure switch from oreilly(it was ~$20). Flushed the compressor also and then used PAG 150 in the compressor reservoir(this was my mistake, I should have torn it down and cleaned/rebuilt it then). I vacuumed it for about 2 hours and then made sure it held vacuum overnight to check for leaks. Then charged it with about 36oz of R134. It worked great for about a year and then blew the compressor shaft seal(common problem on the A6 with the old ceramic shaft seal). It didn't blow until I was on a hunting trip in September, so I never got around to fixing it until the temps warmed up again a few weeks ago. I got a compressor rebuild kit from ebay with the new design double lip shaft seal and tore the whole thing down and rebuilt it. It took about 4 hours, mostly going back and forth trying to get the clutch off the front. Then re-vacuumed and charged the system and it's back to tip-top cooling.

 

[Radiohead]

That sounds like what I need to do man. Thanks for lining it all out for me.

Now, gotta find the independent wealth to make it happen.
edit - probably should try to pull a vacuum now and see what needs replacing so I don't do this twice too.

BTW, is it just me or does any one else wish they had gotten to the put-off **** before the vid screwed the pooch? You know, that new roof you keep putting off, or having had your square squared away before the parts problems, the employee problems and the inflation kicked you in the nads..... just saying

 

[GMC trucker]

Yep, AC flush with solvent and compressed air. Did the evaporator and condenser individually. New manifold and lines(they are a single assembly for the A6) from the compressor to the condenser and from filter/dryer to compressor. New orifice tube(blue) and all new o-rings everywhere. New R134 pressure switch from oreilly(it was ~$20). Flushed the compressor also and then used PAG 150 in the compressor reservoir(this was my mistake, I should have torn it down and cleaned/rebuilt it then). I vacuumed it for about 2 hours and then made sure it held vacuum overnight to check for leaks. Then charged it with about 36oz of R134. It worked great for about a year and then blew the compressor shaft seal(common problem on the A6 with the old ceramic shaft seal). It didn't blow until I was on a hunting trip in September, so I never got around to fixing it until the temps warmed up again a few weeks ago. I got a compressor rebuild kit from ebay with the new design double lip shaft seal and tore the whole thing down and rebuilt it. It took about 4 hours, mostly going back and forth trying to get the clutch off the front. Then re-vacuumed and charged the system and it's back to tip-top cooling.

Did you use the original type tube and fin condenser or a parallel type condenser?
I changed mine over to the parallel condenser type last year, because I couldn’t find an original type tube and fin. I also put 36 oz of 134 refrigerant. It was nice and cold but I noticed my high pressure side was pushing 300-320psi with low side in the 70-85 psi range. A couple days later, I’m guessing when the outside temperature was higher, it popped the compressor high pressure relief valve.
I emptied the system and started over with a 1 hour vacuum then started refilling 134A while watching pressures. At 170-180psi high side and 35-40psi low side, I had 27 oz of 134A in the system. My dash vent outlet was at 37 degrees.
I went with 36 oz of refrigerant based on information on this forum last year.
I don’t think it took into account the parallel flow condenser vs the tube and fin type. The parallel flow condenser (16”x28”x1”) is smaller in dimensions than the original round tube and fin type. Also the round tube I.D. volume is higher than the small rectangular type tubes in the parallel flow type condenser.
Either way, with this month’s temperature running 101-103 in my area, the A/C was still blowing cold “until I got caught in traffic idling for 20-30 minutes at a time”. My engine temperature also came up significantly, from 180 to 235. And as expected my AC temperature went up.
I’m in the process of installing an auxiliary 14” Derale electric fan in front of the condenser. I’ll post results when I get it back together, hopefully by this weekend.

 

[Bextreme04]

Did you use the original type tube and fin condenser or a parallel type condenser?
I changed mine over to the parallel condenser type last year, because I couldn’t find an original type tube and fin. I also put 36 oz of 134 refrigerant. It was nice and cold but I noticed my high pressure side was pushing 300-320psi with low side in the 70-85 psi range. A couple days later, I’m guessing when the outside temperature was higher, it popped the compressor high pressure relief valve.
I emptied the system and started over with a 1 hour vacuum then started refilling 134A while watching pressures. At 170-180psi high side and 35-40psi low side, I had 27 oz of 134A in the system. My dash vent outlet was at 37 degrees.
I went with 36 oz of refrigerant based on information on this forum last year.
I don’t think it took into account the parallel flow condenser vs the tube and fin type. The parallel flow condenser (16”x28”x1”) is smaller in dimensions than the original round tube and fin type. Also the round tube I.D. volume is higher than the small rectangular type tubes in the parallel flow type condenser.
Either way, with this month’s temperature running 101-103 in my area, the A/C was still blowing cold “until I got caught in traffic idling for 20-30 minutes at a time”. My engine temperature also came up significantly, from 180 to 235. And as expected my AC temperature went up.
I’m in the process of installing an auxiliary 14” Derale electric fan in front of the condenser. I’ll post results when I get it back together, hopefully by this weekend.

I still have the original 1980 tube and fin condenser on it. I just straightened up the fins and sent it.

I filled to the expected pressures for the ambient temps, not to a specific weight. I just kept putting in refrigerant until I saw ~40psi low side and ~175 high side. Then checked vent temps and saw ~42 degrees. After a few minutes of driving around it dropped to ~38 degrees and has been solid ever since.

I have dual GM electric fans from a 2009 K2500 pickup and a radiator from a 97 K2500 suburban 454. The low speed comes on when the AC is on and high speed kicks on when the coolant temp gets over 210. With the AC on, the high speed never kicks on even when sitting at idle in 100 degree plus temps. AC blows ice cold all the time, even when stopped for extended times. High speed kicks on when AC is not on and I'm sitting at idle for 5 minutes or more. It will only kick on for about 15 seconds before the coolant temps drop back down enough for them to kick off again and then it takes a few minutes for it to trip again.

I put all that in to prep for a 454/4L80 swap that will use a stock 0411 PCM. The PCM will then control the low/high based on vehicle speed, AC pressure, and engine temps. All of those parameters are accessible and adjustable in the PCM, so it makes it a very versatile system.