Refilling AC

[norwegianvette]

Hi.

Have a 1993 convertible, LT1 with original AC. I want to have this refilled with fresh gass and wonder if anyone can give me some knowledge on this issue. Do i need to replace any parts, name on gass in the system now and the new one used today. I will give the car to a propper firm to do the job but need to know the basics in case they try to fool me with changin parts to add on the bill only :ugh

Steve

 

[Schrade]

Ask questions, which end with the words "Show me". Liars and crooks don't like to show you; they like to talk.

Words go away when the sound stops. Paper don't quit.

 

[crash]

Hi.

Have a 1993 convertible, LT1 with original AC. I want to have this refilled with fresh gass and wonder if anyone can give me some knowledge on this issue. Do i need to replace any parts, name on gass in the system now and the new one used today. I will give the car to a propper firm to do the job but need to know the basics in case they try to fool me with changin parts to add on the bill only :ugh

Steve

well it sounds like you have an r-12 system. first the system needs to be checked for leaks and do whatever repairs are needed. id suggest converting it to r-134a. simple to do. the system needs to be evacuated and the r-12 recovered and stored by the tech that is doing the work. next they will have to remove the schrader valves. then they will have to install new sevice ports. you get these when you buy the r-134a conversion kit and they screw right on the old r-12 service ports. once installed the system will have to evacuated and recharged with r-134a.
put the same amount of r-134a as it took in r-12.
are you can refill it with r-12. its exspensive over here. about $70.00 a lb. if you stay with r-12 make sure it is pure r-12 and not that crap that has propane and other junk in it.
good luck rich

 

[Klaus E.]

I would check the AC label. This system might be a 134 type. Just a suggestion.

Klaus

 

[MusclecarJohn]

I agree Klaus, I'm pretty positive that the Vette went to r134 in 93
but Junk or Hib will def. know for certain

 

[Curious George]

well it sounds like you have an r-12 system. first the system needs to be checked for leaks and do whatever repairs are needed. id suggest converting it to r-134a. simple to do. the system needs to be evacuated and the r-12 recovered and stored by the tech that is doing the work. next they will have to remove the schrader valves. then they will have to install new sevice ports. you get these when you buy the r-134a conversion kit and they screw right on the old r-12 service ports. once installed the system will have to evacuated and recharged with r-134a.
put the same amount of r-134a as it took in r-12.
are you can refill it with r-12. its exspensive over here. about $70.00 a lb. if you stay with r-12 make sure it is pure r-12 and not that crap that has propane and other junk in it.
good luck rich

There is a lot more to converting to R-134 than just changing the service ports, evacuating the system and refilling it. If this is all you do you will certainly have problems in no time at all.

The following procedure will insure that the job is done correctly when converting to R-134:

1. I assume that your current system is working and does not leak and is R-12.
2. Recover the R-12 refrigerant.
3. Remove schrader valves and orifice tube. Make sure system has no pressure.
4. Disconnect and remove the a/c lines and flush them out with mineral spirits. If you cannot remove the lines, then leave them in place and flush. Use compressed air to flush the mineral spirits through the lines. Make sure lines are removed / disconnected from the compressor before flushing.
5. Flush evaporator and condenser too. It will take awhile to flush the lines, evaporator and compressor, but it is worth it. Take your time and do it right.
6. After flushing leave everything open for a few hours to let the mineral spirits residue evaporate.
7. When replacing the a/c lines, use new o-rings everywhere. Do not reuse any old o-rings. Put a little ester oil on each o-ring as you install them.
8. Find out how much oil your system uses and place 1/3 of the total oil in the evaporator, 1/3 in the condenser and 1/3 in the accumulator. I would recommend ester oil. PAG will work, but I have had good luck with ester and a lot of a/c guys recommend it.
9. Replace the Accumulator (with a new one)
10. Take off the compressor and try to drain out as much oil as possible. Some mineral oil will remain in the compressor, but it will not harm the conversion process. It will eventually find its way to the lowest point in the system, which will be at the bottom of the condenser. Reinstall compressor. Do not put any oil into the compressor, it will have enough oil residue until the new oil gets circulating. If it makes you feel better, put in 1 ounce of oil in the compressor and turn the compressor over by hand about 10 times to distrbute the oil inside. Reduce the amount of oil else where to reflect the 1 ounce you added to the compressor.
11. Replace the orifice tube with a slightly smaller orifice tube. I believe the OE Corvette orifice tube is .072" (white), use a Ford (blue) orifice tube that is .067" (carquest / napa part # - 207316). The decreased orifice tube will increase the pressure drop across the tube into the evaporator and help the system work better with R-134.
12. Adjust your low pressure cut-out switch 1/2 turn counter-clockwise. This is a preliminary adjustment and you may have to adjust it more once the system is fully charged. If it is not adjustable, you can purchase a new one that is calibrated for R-134. (These are usually non-adjustable)
13. Install new R-134 service ports. Carquest has some nice steel ones instead of the cheap aluminum ones in those conversion kits. I have had problems with the aluminum ones fitting my gauge connections. The tooling on those cheap aluminum service ports is not that great.
14. Make sure all hoses / fittings are tight. Vaccum the system for 30 minutes. After vacuuming, make sure the system holds a vacuum and there are no leaks.
15. Turn on the a/c and place the blower on "high".
16. Add R-134 to 80% of the amount of R-12 used. For example, if your system required 2.25 lbs. of R-12, then you would add 1.8 lbs. of R-134. The compressor will short cycle until the system has built up pressure.
17. After the correct amount of refrigerant is in the system, turn the blower on "low". The compressor should cut-out at about 19~20 psi. You may have to rev up the motor in order for the clutch to cycle.
18. Your vent temps should be @ 40~42* while cruising if everything goes right.

I have converted three vehicles with the above procedure and they are all working great and I saved a ton of money.

CG

 

[G Winter]

well it sounds like you have an r-12 system. first the system needs to be checked for leaks and do whatever repairs are needed. id suggest converting it to r-134a. simple to do. the system needs to be evacuated and the r-12 recovered and stored by the tech that is doing the work. next they will have to remove the schrader valves. then they will have to install new sevice ports. you get these when you buy the r-134a conversion kit and they screw right on the old r-12 service ports. once installed the system will have to evacuated and recharged with r-134a.
put the same amount of r-134a as it took in r-12.
are you can refill it with r-12. its exspensive over here. about $70.00 a lb. if you stay with r-12 make sure it is pure r-12 and not that crap that has propane and other junk in it.
good luck rich

Pretty much correct except, only 80% 134A by weight. Amount is critical for proper operation.

Glenn

 

[Dad2BJO]

I just had my 93 recharged. It was an r-12 system and I had it converted to 134. They put dye in the system to see where the leaks are if any. I will take it back in a week or two and have it rechecked.

 

[crash]

There is a lot more to converting to R-134 than just changing the service ports, evacuating the system and refilling it. If this is all you do you will certainly have problems in no time at all.

The following procedure will insure that the job is done correctly when converting to R-134:

1. I assume that your current system is working and does not leak and is R-12.
2. Recover the R-12 refrigerant.
3. Remove schrader valves and orifice tube. Make sure system has no pressure.
4. Disconnect and remove the a/c lines and flush them out with mineral spirits. If you cannot remove the lines, then leave them in place and flush. Use compressed air to flush the mineral spirits through the lines. Make sure lines are removed / disconnected from the compressor before flushing.
5. Flush evaporator and condenser too. It will take awhile to flush the lines, evaporator and compressor, but it is worth it. Take your time and do it right.
6. After flushing leave everything open for a few hours to let the mineral spirits residue evaporate.
7. When replacing the a/c lines, use new o-rings everywhere. Do not reuse any old o-rings. Put a little ester oil on each o-ring as you install them.
8. Find out how much oil your system uses and place 1/3 of the total oil in the evaporator, 1/3 in the condenser and 1/3 in the accumulator. I would recommend ester oil. PAG will work, but I have had good luck with ester and a lot of a/c guys recommend it.
9. Replace the Accumulator (with a new one)
10. Take off the compressor and try to drain out as much oil as possible. Some mineral oil will remain in the compressor, but it will not harm the conversion process. It will eventually find its way to the lowest point in the system, which will be at the bottom of the condenser. Reinstall compressor. Do not put any oil into the compressor, it will have enough oil residue until the new oil gets circulating. If it makes you feel better, put in 1 ounce of oil in the compressor and turn the compressor over by hand about 10 times to distrbute the oil inside. Reduce the amount of oil else where to reflect the 1 ounce you added to the compressor.
11. Replace the orifice tube with a slightly smaller orifice tube. I believe the OE Corvette orifice tube is .072" (white), use a Ford (blue) orifice tube that is .067" (carquest / napa part # - 207316). The decreased orifice tube will increase the pressure drop across the tube into the evaporator and help the system work better with R-134.
12. Adjust your low pressure cut-out switch 1/2 turn counter-clockwise. This is a preliminary adjustment and you may have to adjust it more once the system is fully charged. If it is not adjustable, you can purchase a new one that is calibrated for R-134. (These are usually non-adjustable)
13. Install new R-134 service ports. Carquest has some nice steel ones instead of the cheap aluminum ones in those conversion kits. I have had problems with the aluminum ones fitting my gauge connections. The tooling on those cheap aluminum service ports is not that great.
14. Make sure all hoses / fittings are tight. Vaccum the system for 30 minutes. After vacuuming, make sure the system holds a vacuum and there are no leaks.
15. Turn on the a/c and place the blower on "high".
16. Add R-134 to 80% of the amount of R-12 used. For example, if your system required 2.25 lbs. of R-12, then you would add 1.8 lbs. of R-134. The compressor will short cycle until the system has built up pressure.
17. After the correct amount of refrigerant is in the system, turn the blower on "low". The compressor should cut-out at about 19~20 psi. You may have to rev up the motor in order for the clutch to cycle.
18. Your vent temps should be @ 40~42* while cruising if everything goes right.

I have converted three vehicles with the above procedure and they are all working great and I saved a ton of money.

CG

my bad forgot about the drier and oriface tube. they used to say to flush the system also. i forget which pag oil to use but im sure somebody will jump in and suggest it

 

[rlg]

my bad forgot about the drier and oriface tube. they used to say to flush the system also. i forget which pag oil to use but im sure somebody will jump in and suggest it

use ester oil , it is compatible with all freons.

 

[Klaus E.]

I would have one suggestion on flushing. Since compressed air is not always the cleanest product, I wopuld recommend using nitrogen. It's extremely dry and clean out a copressed gas bottle, which you can ourchase or rent. It would do a much better job of removing moisture than compressed air, which usually contains at least some amount of moisture. Further, you can also use nitrogen instead of air in you tires; they'll run a little cooler and probably las a little longer. All four of my vehicles have tires filled with nitrogen. If you have a Costco in your area, they will fill your tires for free.

Klaus

 

[geekinavette]

Ever looked at the MSDS for R134A? You couldn't pay me to touch that stuff. Why industry still uses it is beyond me.

That "crap that has propane in it" (hydrocarbon based refrigerant) is by far superior in efficiency to R134A (flourocarbon based refrigerant). That's not to say that it gets that much colder, it means that your compressor has to do MUCH less work. You do not have to go through the painful flushing that is required with the R134A conversion as both R12 and R134 oils are compatible (definitely do the new O-rings though). Now if the system is contaminated, then yes definitely go through the flushing, but it is not necessary due to incompatible oils. You also do not need to pull a vaccum on the system as the small amount of moisture in air will not effect operation. I have used this stuff in 4 different cars (Envirosafe), including the '84 Vette, and have had very good results with it. It is neither toxic (unlike R134, a proven carcinogen) nor harmful to the environment (also unlike R134).

Here's to staying :cool !!

 

[G Winter]

I have some of the what I think is the propane based refrigerant . Has an oak leaf on it , think made in Canada.
I haven't use it because of a little concern about it being flammable . After much consideration (having spent quite a few yrs in the LP business) I have decided that the only real problem would be getting burnt. A leak at the right place and time could cause a short duration fire, even a torch like effect.
The quantity wouldn't be enough to likely cause any kind of explosion.
I do agree with geek that the 134A is bad stuff. The switch to it was more because of the Dupont lobby, (they had the patent on the stuff,) than it was environmental .

Glenn

 

[gmjunkie]

I agree Klaus, I'm pretty positive that the Vette went to r134 in 93
but Junk or Hib will def. know for certain

1994 was the first year for Corvette to use 134a,1995 was the first on the rest of GM vehicles!!

 

[geekinavette]

Using hydrocarbon based refrigerants is no more "dangerous" from a flammability perspective than filling the car up with gasoline.

Besides...any AC system has flammable oil in it.

 

[gmjunkie]

There is a lot more to converting to R-134 than just changing the service ports, evacuating the system and refilling it. If this is all you do you will certainly have problems in no time at all.

The following procedure will insure that the job is done correctly when converting to R-134:

1. I assume that your current system is working and does not leak and is R-12.
2. Recover the R-12 refrigerant.
3. Remove schrader valves and orifice tube. Make sure system has no pressure.
4. Disconnect and remove the a/c lines and flush them out with mineral spirits. If you cannot remove the lines, then leave them in place and flush. Use compressed air to flush the mineral spirits through the lines. Make sure lines are removed / disconnected from the compressor before flushing.
5. Flush evaporator and condenser too. It will take awhile to flush the lines, evaporator and compressor, but it is worth it. Take your time and do it right.
6. After flushing leave everything open for a few hours to let the mineral spirits residue evaporate.
7. When replacing the a/c lines, use new o-rings everywhere. Do not reuse any old o-rings. Put a little ester oil on each o-ring as you install them.
8. Find out how much oil your system uses and place 1/3 of the total oil in the evaporator, 1/3 in the condenser and 1/3 in the accumulator. I would recommend ester oil. PAG will work, but I have had good luck with ester and a lot of a/c guys recommend it.
9. Replace the Accumulator (with a new one)
10. Take off the compressor and try to drain out as much oil as possible. Some mineral oil will remain in the compressor, but it will not harm the conversion process. It will eventually find its way to the lowest point in the system, which will be at the bottom of the condenser. Reinstall compressor. Do not put any oil into the compressor, it will have enough oil residue until the new oil gets circulating. If it makes you feel better, put in 1 ounce of oil in the compressor and turn the compressor over by hand about 10 times to distrbute the oil inside. Reduce the amount of oil else where to reflect the 1 ounce you added to the compressor.
11. Replace the orifice tube with a slightly smaller orifice tube. I believe the OE Corvette orifice tube is .072" (white), use a Ford (blue) orifice tube that is .067" (carquest / napa part # - 207316). The decreased orifice tube will increase the pressure drop across the tube into the evaporator and help the system work better with R-134.
12. Adjust your low pressure cut-out switch 1/2 turn counter-clockwise. This is a preliminary adjustment and you may have to adjust it more once the system is fully charged. If it is not adjustable, you can purchase a new one that is calibrated for R-134. (These are usually non-adjustable)
13. Install new R-134 service ports. Carquest has some nice steel ones instead of the cheap aluminum ones in those conversion kits. I have had problems with the aluminum ones fitting my gauge connections. The tooling on those cheap aluminum service ports is not that great.
14. Make sure all hoses / fittings are tight. Vaccum the system for 30 minutes. After vacuuming, make sure the system holds a vacuum and there are no leaks.
15. Turn on the a/c and place the blower on "high".
16. Add R-134 to 80% of the amount of R-12 used. For example, if your system required 2.25 lbs. of R-12, then you would add 1.8 lbs. of R-134. The compressor will short cycle until the system has built up pressure.
17. After the correct amount of refrigerant is in the system, turn the blower on "low". The compressor should cut-out at about 19~20 psi. You may have to rev up the motor in order for the clutch to cycle.
18. Your vent temps should be @ 40~42* while cruising if everything goes right.

I have converted three vehicles with the above procedure and they are all working great and I saved a ton of money.

CG

I agree with most of this but with only 80% charge of 134a,one of these days under the right climate conditions your going to have a major Freeze Up!!:ugh:ugh:ugh It "Will" be very detrimental to your system if left unchecked!! Big Boy's down at the pool hall say 10% less 134a than R12!! (+/- 1 oz.) Once a freeze up occurs you may not even know it till the desiccant in the accumulator starts circulating in the system and stopping the oil flow to the compressor and it LOCKS Up!!

As far as having to rev the engine to make it cycle,thats not necessary.
Just un-plug the blower motor,If properly charged it will start cycling within a minute or so!

As far as the oil gos I personally use Ester Oil and recommend it!
But 1/3 of it is going in the compressor,1/3 in the accumulator,1/3 in the condenser.No need in putting it in the evaporator,It'll be there within about 2 seconds of compressor start up!!

PS Don't forget to purge your gauges before you start charging,some gauge sets can hold up to 8 oz of refrigerant and you will be under charged it if you don't!