Have an 87Gt which as we all know was born with R12 refrigerant. I am restoring this car, has been in storage for 15-20 years.
There is no r12 refrigerant in the system at this time. Leaked out I’m sure over time and lack of use.
I can check for leaks and recharge with R12 which is expensive to obtain .
Or
I can convert to R134. I have a new accumulator/receiver dryer, and tube to install. I have no knowledge whether compressor is good or bad.
The questions I see are: 1. Refrigerant oil in compressor, but is R12 oil. Do I have to clean old oil out of compressor before adding PAG oil? 2. Is it worth the effort, or replace the compressor and use the PAG oil ( cost for compressor $200 about same for R12 refrigerant. I am basically asking for a recommendation as to which direction to choose. Any advise gladly accepted.
System is empty, hasn't worked for an indeterminate amount of time, and compressor is likely bad. Replace the compressor with new and convert to R-134A. I would only stay with R-12 at this point if the car is a museum piece or was recently working with R-12 and a minor leak was repaired.
Thank you for our recommendation. I was really unsure whether to go through the process for inputting R12 again and finding a bad compressor after all that expense. I feel replacing the compressor, oil, R134 is more of a sure bet.
I have been looking but can’t find the refrigerant capacity for the system, any idea what the old R12 capacity is? (I can reduce to the 85% for the R134)
Also, the compressor type? This is an 87GT with the 2.8 V6.
The parts houses seem to think theirs (H6 I believes the one)
Thank you
[This message has been edited by Sledgehammer (edited 05-30-2020).]
Original R-12 capacity is 2.5lbs, so yes the R-134A capacity is 80-90% of that, which works out to about 3 12oz cans. Other than the new high and low side adapter fittings, the only other change is adjusting the cycling switch on the accumulator to 21psi instead of the R-12's 25psi.
Oil capacity for R-12 is 8oz of 525 viscosity mineral oil. For an R-134A conversion, it's 8oz of whatever the compressor manufacturer recommends, usually PAG46, but some people swear by Ester oil for conversions.
Original compressor for an 87 GT is either a DA6 or an HR6, the changeover took place around the 1987 model year. Ask for a new compressor, it will have an improved internal design while being externally identical to the DA6/HR6 design (they're indistinguishable externally). The Four Seasons 58255 is a good one.
Original R-12 capacity is 2.5lbs, so yes the R-134A capacity is 80-90% of that, which works out to about 3 12oz cans. Other than the new high and low side adapter fittings, the only other change is adjusting the cycling switch on the accumulator to 21psi instead of the R-12's 25psi.
Oil capacity for R-12 is 8oz of 525 viscosity mineral oil. For an R-134A conversion, it's 8oz of whatever the compressor manufacturer recommends, usually PAG46, but some people swear by Ester oil for conversions.
Original compressor for an 87 GT is either a DA6 or an HR6, the changeover took place around the 1987 model year. Ask for a new compressor, it will have an improved internal design while being externally identical to the DA6/HR6 design (they're indistinguishable externally). The Four Seasons 58255 is a good one.
Good info but PAG oil is recommended for use in only new R-134a installations .Ester oil is what is recommended for R-134a conversions as it will mix with the 525 oil residue . PAG oil does not do this.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
Good info but PAG oil is recommended for use in only new R-134a installations .Ester oil is what is recommended for R-134a conversions as it will mix with the 525 oil residue . PAG oil does not do this.
I see 3 types of Orfice tubes shown. Which one is recommended Standard, variable, extreme? Also I understand that one should adjust the low side pressure switch. Is that an arbitrary 1/8-1/4 counter clockwise turn on the adjustment screw or ?
When I purchase the accumulator I also bought an orfice tube. It looks like a “standard”
Everyone agree on “Ester oil” for the retrofit, (8 oz ) In my case the only residue would be in the hoses.
[This message has been edited by Sledgehammer (edited 05-30-2020).]
The more expensive $30 variable ones are made to improve cooling when the car is stopped, like in traffic or just idling. It's meant to more closely mimic the operation of the thermal expansion valve used by most non-GM systems. Standard VS Variable though, nobody seems to agree if it's worth it or not. One thing to consider is it introduces moving parts to what previously was dead simple, introducing a potential failure point.
If you can get good performance from the standard one, I wouldn't bother upgrading. If the standard orifice tube doesn't perform well at idle or in traffic, it may be worth trying to see if conditions improve.
The procedure to adjust the cycling switch is to unplug it, turn the screw clockwise or counterclockwise half a turn, plug the connector back in, and observe the reading on the low side gauge. If it's now above 25, turn the screw the other direction. If it doesn't get down to 21, keep turning until it does. Lower than 21, you went too far. Or just buy the switch pre-calibrated for R-134A @ 21psi.
One last question : There are shrader valves on the service ports, there are shrader valves on the conversion adaptors. Are the existing shrader vale’s on the service ports removed when installing the conversion adaptors?
Yes, you only want one schrader valve per port. Good conversion fittings will have their own valves, like the ones in the parts list. Remove the valve from the Fiero's high side line, and one of the two ports on the accumulator where you will install the conversion fitting. Leave the other valve on the port for the cycling switch. The Fiero's high side schrader valve is larger than the more typical tire-type valve in the other ports, that is what the special valve core tool is for.
Sledgehammer's question seemes similar to mine, so I'm going to post here. When I bought my 1988 4cyl Fiero the previous owner, who'd had it for about 18 months, said that the A/C didn't work. He gave no specifics beyond that. Here's what I've learned: 1) When turned on, the system does not cool the interior of the car. So, it wasn't like the previous owner didn't know where the A/C on/off switch was or anything. I was kind of hoping for that, but I guess I was a little optimistic. 2) The compressor appears to kick in and its clutch appears to function. When I turn on/off the A/C I can hear the clutch kick in. Also, my rev's change indicating that the clutch is putting a load on the system. 3) The system appears to pressurize at least a little. It was probably wrong, but I let a little air/gas out through the schrader valve at the top of the accumulator and I got an encouraging hiss.
Here's what I don't know: 1) Is this system set up for R12? How can I be sure? The accumulator has, what I've been led to believe are R12 type fittings (Shrader valves) and there's a sticker with "R-12" on it: 2) If the system is set up for R-12, what else do I need to know in order to make a decision regarding topping off with R12 or going to R134a? After 32 years is it possible that the system will still work with just a charge of R-12? I know for a fact that the car spent many years in Arizona, so it is very likely it's A/C got a regular workout.
The information that I provide was given to me by a tech in a local Automotive A/C shop who I learned from. I always go with what the pros tell me. Its always worked on the systems that I converted over to R-134a , so disagree if you like. The knowledge and value has been proven on this end.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
Originally posted by RWDPLZ: There he is! What took so long?
What he said is true. If the system has "R12" oil in it, use Ester oil. If it's been completely rebuilt and flushed, use PAG.
With that said... it's been my experience that compressor manufacturers/remanufacturers will not warranty a compressor unless you have proof-of-purchase for a new accumulator/dryer, and possibly orifice tube, too. At that point, almost all of the old oil is gone, anyway. Not much more trouble to just flush the entire system and refill it with PAG.
1) Is this system set up for R12? How can I be sure? The accumulator has, what I've been led to believe are R12 type fittings (Shrader valves) and there's a sticker with "R-12" on it: 2) If the system is set up for R-12, what else do I need to know in order to make a decision regarding topping off with R12 or going to R134a? After 32 years is it possible that the system will still work with just a charge of R-12? I know for a fact that the car spent many years in Arizona, so it is very likely it's A/C got a regular workout.
Thanks again!
1. Yes, that system is still set up for R-12, the ports don't have the conversion fittings and no sign of a conversion sticker. 2. You need to determine if the system has any charge. You can press a screwdriver tip on one of the schrader valves briefly and see if anything comes out, if there is pressure, you'll need a gauge set to determine the state of charge.
Typically, an R12 system converted to R134 will not perform as well as it did originally. There are things you can do to help, like use a variable orifice valve instead of the factory fixed orifice valve, but those don't change the fact that the condenser designed for R12 is not as good with R134 as it is with R12, and conversely, does not perform as well with R134 as a condenser designed for R134 would. I have not heard of a drop-in R134 style condenser for the Fiero.
Also, R134 is more sensitive to charge weight than R12. An R12 system can be charged fairly correctly by watching the high side/low side pressures, while an R134 system is difficult to charge correctly by watching pressures. To really charge an R134 system correctly, you need to vacuum the system down and then blow in the correct weight of refrigerant... this is much more difficult to DIY.
Also, the reason an R12 system needs to be vacuumed extensively is that R12 reacts with moisture to form corrosive compounds. The R12 replacement refrigerants do not, making it easier to vacuum the system out as the requirements are less stringent.
All that being said, don't bother converting to R134... it's more trouble than it's worth and you'll get a system that doesn't work as well as original.
You *WILL* need a new compressor and dryer and the right oil for your refrigerant choice.
I can't recommend a variable orifice valve enough... it really broadens the window of RPM and vehicle speed at which you get max A/C effectiveness.
[This message has been edited by Will (edited 07-20-2020).]
You *WILL* need a new compressor and dryer and the right oil for your refrigerant choice.
I can't recommend a variable orifice valve enough... it really broadens the window of RPM and vehicle speed at which you get max A/C effectiveness.
Thanks for the detailed response, I'm thinking you're referring to the "Artic Air for R12 Systems" product in the above link? Looks reasonable.
I get that I will need a new dryer, but why will I need a new compressor? Is it just very very likely given the age of the vehicle, how long it has been since the AC worked, etc?
The refrigerant oil for the compressor would be ester oil since it's R-12 (like?), right?
For sure I'll be getting a variable orifice valve.
[This message has been edited by gjgpff (edited 07-21-2020).]
1. Yes, that system is still set up for R-12, the ports don't have the conversion fittings and no sign of a conversion sticker. 2. You need to determine if the system has any charge. You can press a screwdriver tip on one of the schrader valves briefly and see if anything comes out, if there is pressure, you'll need a gauge set to determine the state of charge.
So, the schrader valve already gives a hiss when pressed, therefore I'll be using a gauge to determine how much charge is in there and/or removing any R-12 that is present, right?
I'm kind of convinced by Will's reasoning to go the R-12 route instead of R-134a, but there's still alot of figuring out to do.
R-12 replacements are typically propane or other flammable gas based, and a bad idea. People typically go this route because they want a cheap, easy fix. They are not NHTSA approved and can be very dangerous.
R-12 oil is 525 viscosity mineral oil, not ester oil. Total Fiero capacity is 8 oz
If pressing the schrader valve gave a weak hiss, it's likely empty, if it was a strong loud hiss it might be partially charged, a gauge set is the only way to tell.
It is possible to get an R-12 system functional again, but the gas is prohibitively expensive. Fiero capacity is 2.5lbs, and you need EPA section 609 certification to purchase it (you can take and pass the test online, really easy). Few shops will service an R-12 system anymore unless you live in a highly populated desert region (and no shop will touch an alternative refrigerant system). The reason is shops are required to have separate systems for different refrigerant types. A dedicated A/C shop may be able to afford this, but most smaller shops won't put up with the expense.
You need a new accumulator (dryer) to replace the desiccant that is likely saturated with moisture at this point. A new compressor is a good idea as the originals are all 30+ years old at this point, and tend to be the primary source of leaks, at the shaft seal or body o-rings.
An R-134A conversion that is done PROPERLY will cool 90%+ as well as an R-12 charged system. Charging by weight not pressure is key. 3 12oz cans is close enough.
Ester oil was introduced and sold by the automotive aftermarket (adapted from residential/commercial refrigeration systems) specifically for use in conversions when it was widely believed that mixing mineral and PAG oils resulted in a corrosive substance. However, it is not supported by any of the OEM's or reputable aftermarket compressor manufacturers. According to AC Delco 'Guidelines for Retrofitting Vehicles to R-134a' Page 16:
quote
5. PAG or V5 Oil Compatibility Contrary to information published to date outside of ACDelco, mineral oil and PAG or V5 oil are chemically compatible. The mineral oil left in the system after reclaiming the R-12 can remain in the system with no harmful effects. However, the mineral oil will not mix with the R-134a, and so will not circulate and perform its lubricating function. Testing has shown that most of the mineral oil will eventually collect in the accumulator. The system will operate properly as long as refrigerant charge amounts are strictly adhered to.
6. Retrofit Charge Level The retrofit R-134a charge level is more critical than with R-12 systems. Overcharging may push the mineral oil out of the A/D and cause it to circulate as a liquid. This is more likely to result in compressor damage. Undercharging may lead to loss of performance
This is why you want to remove as much of the old mineral oil as possible. Replacing the accumulator and compressor will eliminate most of it, and flushing the lines and evaporator will replace the majority of the rest. Many people have used ester and it worked, but it will void any warranty for a compressor. Ester is also only available in 100 viscosity, where PAG is available in many ranging from 46 to 150, the correct viscosity dictated by compressor design.
R-12 replacements are typically propane or other flammable gas based, and a bad idea. People typically go this route because they want a cheap, easy fix. They are not NHTSA approved and can be very dangerous.
R-12 oil is 525 viscosity mineral oil, not ester oil. Total Fiero capacity is 8 oz
If pressing the schrader valve gave a weak hiss, it's likely empty, if it was a strong loud hiss it might be partially charged, a gauge set is the only way to tell.
It is possible to get an R-12 system functional again, but the gas is prohibitively expensive. Fiero capacity is 2.5lbs, and you need EPA section 609 certification to purchase it (you can take and pass the test online, really easy). Few shops will service an R-12 system anymore unless you live in a highly populated desert region (and no shop will touch an alternative refrigerant system). The reason is shops are required to have separate systems for different refrigerant types. A dedicated A/C shop may be able to afford this, but most smaller shops won't put up with the expense.
You need a new accumulator (dryer) to replace the desiccant that is likely saturated with moisture at this point. A new compressor is a good idea as the originals are all 30+ years old at this point, and tend to be the primary source of leaks, at the shaft seal or body o-rings.
An R-134A conversion that is done PROPERLY will cool 90%+ as well as an R-12 charged system. Charging by weight not pressure is key. 3 12oz cans is close enough.
Ester oil was introduced and sold by the automotive aftermarket (adapted from residential/commercial refrigeration systems) specifically for use in conversions when it was widely believed that mixing mineral and PAG oils resulted in a corrosive substance. However, it is not supported by any of the OEM's or reputable aftermarket compressor manufacturers. According to AC Delco 'Guidelines for Retrofitting Vehicles to R-134a' Page 16:
This is why you want to remove as much of the old mineral oil as possible. Replacing the accumulator and compressor will eliminate most of it, and flushing the lines and evaporator will replace the majority of the rest. Many people have used ester and it worked, but it will void any warranty for a compressor. Ester is also only available in 100 viscosity, where PAG is available in many ranging from 46 to 150, the correct viscosity dictated by compressor design.
So, this comment and comparing prices for R-12 vs R-134a has kind of convinced me to retrofit. I've also done some looking around to see what's involved in a compressor retrofit and it looks do-able, assuming I can find a way to acquire/borrow some of the specialized tools.
So, my plan right now is the following: 1) Pump out any remaining R-12 in the system. 2) Get a "no A/C" belt, and remove the compressor, and the hoses to it, plugging them and storing them somewhere clean and dry. Also, plug the system so it stays as clean as it is prior to flushing it. 3) Refurbish the compressor as time permits. I'll try to follow this youtube video: "Delphi Harrison V5 A/C Compressor - Full Teardown and Reseal" 4) When the compressor is ready.. or the refurbish failed and I get a new compressor, install, flush everything, vacuum test, replace other gaskets, etc. 5) Charge with R134a. 6) Chill
Does anyone have tips/advice regarding getting the loan of specialized pullers, tools, etc?
[This message has been edited by gjgpff (edited 07-22-2020).]
