cptpain

iTrader: (1)

the last 2 years that i've owned my GSL-SE it was fine. everything worked including a/c(wish it was colder but no money for recharge)... a year after owning it the a/c was calling it quits an decided not to blow cold. then just about a few months ago after a rebuild the a/c compressor does not engage at all whatsoever. the compressor is connected to the green connector

Summer is coming and here in texas temps are already 80-90's here.

how do i fix this non engagement problem, and how do i make sure my a/c system is in good order. i'd really hate to remove a/c, as i work all day outside and lose about 20-30lbs just in the summer months each year(and its difficult to regain it, especially when i weigh 140, i started this work when i weighed 175)

Rx-7Doctor

iTrader: (13)

The number one cause of the compressor not coming on is being low on Freon. There is a low pressure safety switch located in one of your A/C lines that monitors the pressure. When the freon level becomes too low it will not allow the compressor to engage. This is to prevent the compressor from burning up.

Because you are in Texas and the humidity and heat sometimes are overbearing. I know because I spent 3 years there. You would be better off biting the bullet and having a shop reservice the system with R12. It will be expensive because of the cost of R12. When I mean service. I mean that they check the complete system for leaks either with dye or a Halon sniffer. Then they evacuate the whole system, put it back on a vacuum to make sure there are no leaks again and recharge.
The option is to retro to R134a. There are kits that are designed to allow the blending of the R134a oil without pulling any existing oil out of the system. I don't recommend it though. You would also want to change out the receiver drier if you were changing to R134a. Which means you would have to open up the system.
The good thing is that our evaporator cores are pretty good size and that helps with the usage of R134a because of the somewhat higher pressures. The downside to R134a is that it won't cool as well as R12 and because of the smaller molecules of the freon, They tend to leak more after time.
The plus side is if you do retro. Then if it does need topping off you can do it yourself.

dantheman

iTrader: (4)

I converted over my CRX to r134, and it definatly doesn't get as cold as r-12, but it does get cold. With the going price of freon at $20 for a 14oz can, it gets VERY expensive to get it done. Also costs around 30-50 just to get someone to put the freon into the car.

I think that I am going to convert mine over in the near future. I am low on freon as it is, and I need to change out the oriface valve as it is. Really easy to do. You can rent the vac pump from Autozone along with the gauges for about $80 and you get that all back when you return it. r134 is also dirt cheep.

If you want, bring your car down to College Station and I can convert it for you. I am nice and cheep as well. Buy me a beer.

djjjr42

Dan, I used to work in the a/c industry but its been a while. Aren't you supposed to use a proper recovery system to remove and contain the R12? I think the EPA was fining like $10k for venting CFCs last time I checked. That is, if they catch you....

dantheman

iTrader: (4)

This is true. This is actually VERY true.

I assume that the car has no freon left in it. That is how my CRX was. I am going to have a local shop pull all the r12 in my system out. They are going to give me a few bucks for it as they know that it is pure stuff.

Now if the car came to me without anything it, I am not going to ask where the r-12 went to.


I want to think though, that you can mix r12 and r134. I have never done this, but I have heard of others who have. I am going to research this and come back and update this thread.

capt murph

There are other options for refrigerant -many R-12 substitutes -that still retain/work with the mineral oil, which is what R-12 uses. Google on R-12 substitute to see.

The POE synthetic oil needed for R-134a does not lubricate or transport in the same manner as does the mineral oil. Hence, compressor lubrication suffers. It will not last as long. POE oil and mineral oil in mix causes a white milky appearance and causes other problems/losses. Getting all the mineral oil out to convert can be difficult at best.

Secondly, R-134a has much less 'cooling energy' , or enthalpy. SO you lose cooling capacity.

I work on large cooling equipment. When we convert from R-22 to r-134a, the capacity changes -drops -by 36%. People think it is greener, but it runs much longer and uses more electricity. They miss that point.

I am not an advocate of converting for this and other reasons. The systems are designed for R-12, or something very close to it. R-134a is not close. HOT SHOT is one name brand for a replacement that comes to mind.

If you have any R-12 in your system, such that air did not enter the system, you could just TOP OFF with hot shot, as R-22 and R-12 blend together very well. If air enters the system, then you need to remove that air via a vacuum process.

That is what I would do... when I run out of R-12.

capt murph

Attached is a sheet on HOT SHOT

capt murph

second attempt w ZIP file...sht and hell. Now it says 1 MB is max... first it said 2 MB was max for pdf...now 1 MB is max for zip file. Sorry guys, I tried.

dantheman

iTrader: (4)

So, if we are going to convert a system to 134, is the compressor in the 7 compatable with it? I can't find any info on that part anyplace. If so, then just replace the drier, replace the oil, pull a vac, hold the vac for a while to boil out any water in the lines and fill.

dantheman

iTrader: (4)

http://www.icorinternational.com/ind...&products_id=4

This stuff looks pretty good!

Rx-7Doctor

iTrader: (13)

The sanden compressor units are strong units and if they are in fairly good shape seal wise internally will be ok with R134a. The drier is a must on using R134a swaps because the desicant (drier) inside the receiver drier is different. I should of clarified my statement on retro on the blending of the system. The correct statement is that all the R12 has to be gone then the kit has the additive to allow the existing R12 oil to blend in with the newly added requirements of the R134a oil.

Dan, evacuating the system is what they do to remove all of the contaminants in the system. No water is in the system, that is what will destroy a system. That's why you do not leave a A/C unsealed at anytime. The vacuum pump is designed to remove the air in the system and make mure that it holds to avoid the presence of possible leaks.

I am not an advocate of substitutes. This is from my experience in the Automotive repair business. I had seen too many failures of the systems with the blends such as Freeze 12.
The drop in efficeny in automotive applications from R12 to R134a would be approx 10-15% and this is variable depending on the size of the evaporator core. And as I had stated the ones in our cars are a decent size. R22 as far as I know has alot higher pressures than R12 does.

In alot of our cars at the evaporator box inside the car is a adjustable sensor that allows us to change the amount of freon that is going thru the expansion valve. This allows you to raise or lower the temp in the vents. So If yours is equipped with this you should be able to get the vehicle cool enough even with R134a.

trochoid

iTrader: (6)

doc, question on the reciever/drier while we're on the subject. On my 2nd gen, which leaks out all of the R-12 in less than 6 months, I've bought a new reciever/drier and o-ring kit for with the intentions of converting it over to a substitute so I can recharge it myself, after a good evac. Suggestions, recommendations, yea/nay?

Rx-7Doctor

iTrader: (13)

The Fc's actually have better compressors on them and all of the R134a conversions I have seen work very well. I believe the key to a good retro is the evacuation process. When people do the conversion themselves and just put the R134a kit on without doing anything else that's when they get failures. It is beneficial to get all of the old freon,oil and whatever microscopic contaminants out of the system before converting. I have had the R134a Done in the past on my previous DD which was a 93 Eclipse. Even in the harsh summers where I worked and it was regularly over 100 deg it blew very cold air.

Reminder, did you get my pm?

trochoid

iTrader: (6)

Thanks doc, that's promising news for this simmer, lol. I got your PM. When I get out to the shop I'll look around, I think I have what you need. Do you need a dashpot too? PM me your addy and I'll get the parts out by Fri as a freebie.

dantheman

iTrader: (4)

Hmmm, I actually have an FC compressor sitting up in my attic! I wonder how hard it would be to swap over.

With that knowledge, I am definatly just going to convert mine over. I was planning on flushing the system with mineral spirits and replacing the dryer anyway, so that will help.

Stevan

iTrader: (17)

This is one of of my hobbies, LOTS of reading, not a lot of hands on, but...
Evacuating(pulling a vacuum) is done to remove air, and moisture thats in the air, that gets in when you open the system. Then the refrigerant is charged into the vacuum so only refrigerant and oil are present in the system.
Contamination other than gases/air/moisture will not be removed with evacuation, flushing is needed to do that (with a solvent), and you can't flush through the expansion valve on the evaporator coil under the dash. So, you have to remove the evap coil, and the exp valve from it to flush it. Also you don't flush the reciever/drier, or the compressor. Install the reciever/drier just before you evac. the system, and only flush the compressor with the correct oil for the refrigerant your'e going to use. So really you can only flush the evap coil, and the condenser coil (in front of the radiator), and the hoses.

From what Iv'e read, the condenser coil is the weak link when converting to 134a, and even on our cars with r-12. It's what needs to get rid of all the heat. Parallel flow condensers are recomended when converting.

The Hot Shot, that Dan mentioned is 50% r-22, 39%r-124, 9.5%r142b, 1.5%r-600a. The other components mixed with r-22 lower the pressure to the vicinity of r-12.
It's supposed to 8%, IIRC, more efiecient than r-12, but there are cons to using alternatives/blends.

Lots of info here,
http://www.autoacforum.com/categorie...=20&zb=1763488

Oh, and to answer the thread starters question, as Doc stated you are probably low on refrigerant, you can test it by jumping the 2 wires together on the low/hi pressure cut out switch on the reciever/drier.
The easiest fix is to find someone to top it of.

trochoid

iTrader: (6)

The FCs have 2 different compressors, 1 is a Sanden, can't think of the other brand atm. The line sets that connect to the compressors are different and not interchangeable.

Another consideration is the mounting position between the 2 gens is different with the ac on top of the ps on the FBs, reversed for the FCs and the mounting brackets correspondingly different.

dantheman

iTrader: (4)

There is alot of information in this thread so far. Let me see if I can make a list of steps that one should take when they convert to 134.

1. Find out why your current system is not working. If you don't feal like you are able to troubleshoot this, take it to an A/C shop for testing.
2. If it is just low on r-12, stick with r-12.
3. If there are problems, replace the parts and buy a new reciver/drier. Do not uncap and play with the drier at this time. :P
4. Replace any seals that you want to while you have the system open. Also, if you feal really ambitious, you can flush out the system. Disconnect the compressor, drier and expansion valve. Follow the directions here: http://bernardembden.com/xjs/134/index.htm Mineral spirits work well as the solvent. Make sure you dry it out well with compressed air.
5. If you have a new compressor, fill it with PAG oil, if not, drain out the old oil and replace with the same amount of new stuff. DON"T use the r-134 with oil already in it. That stuff isn't any good.
6. Bolt up the system. You can now open up the dryer, but hook it up last so the least amount of ambient air touches it.
7. Use the vac pump that you rented to pull a vacume on the system. I pull a vacume on the system and then verify it holds that pressure for a good bit. If the gauges havn't moved in 30 min I say it is good enough. I then turn the pump back on and let it run for several hours. This is supposed to boil out the water that might be in the system.
8. Put in your new 134. How much to put in is a good question. They say it should be 80% of the amount of r-12 that is in there.

Ok, SO where is this valve that can be turned under the dash, and where can we find a parallel condenser coil?

Rx-7Doctor

iTrader: (13)

Steven , Thanks for straightening up the terminology usage. You are correct in the flushing of the system. Normally what most places uses is a A/C flush that is used to clean out all the contaminants. Alot of them will undo the various hoses at each joining ends to do this. You can also use brake clean to achieve the same thing because it dries evaporate free leaving no residues.

Rx-7Doctor

iTrader: (13)

Everything looks good.
Don't worry about the A/C condenser. Ours are of very good size and are more than efficent for the R134a retro.

On the flushing if your ambitious part. I'd would say that you would want to make it a prioriry. The #1 cause of failed A/C compressors is foreign contaminants in the system. Inside of a A/C compressor there is Zero tolerance for any foreign material. It has been stated by A/C manufactures that something as small as a human hair can cause failure of the compressor.
How true that is, I don't know. I do know that over the years while I was in the Automotive service industry that I had to sit thru recerification of A/C systems even as a Service Manager.

As far as the rheostat adjustment to regulate the flow of freon out of the expansion valve if yours is equipped. It would be located on top of the evaporator core box in the passengerside of the vehicle.
This is only to be adjusted after a full charge has been performed and with a thermometer in the vents.

cptpain

iTrader: (1)

ok i already know i dont have any freon at all in my system, so that means that my compressor wont engage correct?

so now what i want to do is before anything else and charging the system is to make sure the system itself is in good order.... how can i go about this? the links provided were not much of a good help and i really want to save the cash of going to an a/c shop until i am for sure that i cant do it on my own....


anybody else?....

Rx-7Doctor

iTrader: (13)

Every thing has been covered. What other info do you need?
If there is no freon then there is a leak. It could be the compressor it's self is leaking. It could be a hose or the condenser or anyother part in the system.

If you are going to try and diagnose it yourself then you will need to get some a/c dye that you can inject into the system. Then enough freon to not damage the compressor when you bypass the electrical system and give power to the compressor. Depending on the type of dye that you use it may require a UV light to see or they may have a visual dye that you can see with the naked eye.
Once you find the leak, then you can repair it and service the system.

cptpain

iTrader: (1)

yea sorry, i found what i needed...

so i just get the dye an put it in along with freon and see where its coming from right?
my dad who recharged it when he gave it to me converted to r134, and when we were trying to recharge it again after the rebuild we took it to a guy who put r12 in it, i dont remember if he completely evacuated it so there might be a combination of both


BTW, i have a parts car which has a/c parts(which worked wonderfully before it was wrecked) so if anything was leaking i can salvage those parts

either way if i cant do it myself im going to...OMG!!! take it to a shop.....

trochoid

iTrader: (6)

If you need to break open the system, I've found both the reciever/dryer and complete o-ring kits on eBay. I've had both laying arounf for over 2 years for the FC, just never got around to installing them. I think I spent less than 60 bucks for both of them together.

dantheman

iTrader: (4)

Dryer is $25 from autozone and the rings are also very cheap.