I know many of the people here want to get their engine cool and have many questions removing the a/c. But, im in texas and my car has black interior where you can cook yourself, and im tired of sweating all the time during the summer. The a/c has always worked marginally at best when its hot, but i seriously want it to freeze me. I worked hard to save enough money to buy a : new R-134a compressor (not rebuilt), new receiver/drier, orifice tube, new A/C hoses from the dealer, bigger TWO row condensor that i found on a firebird (used and flushed), had a mechanic install all parts and add appropriate PAG oil and added the correct amount of R-134a. It cools somewhat, but it doesnt really get cold. When the temp is under 40 degrees it blows ice cubes, but at normal hot days, its almost better to just open the windows. Anyone have any ideas? The system has been completely flushed, the only thing i did not change was the evaporator coil. Someone told me that if i changed out the Evap coil with a larger one that i would be able to compensate for the R134a's lower efficientcy. I have contacted several A/C companies around town and they make it sound like im talking about martian landings. When the car gets over 160-170 the cooling immediately starts to drop to the point at 200 where its just blowing air. Hopefully when i install the dual fan 2500CFM setup that will help, anyone got any suggestions?
Thanks for your help

what i got:
modine aluminum radiator
160* thermostat (hayden relay control for fan)
2 row condensor coil
new hoses
new orifice tube/ receiver-drier
new R-4 updated compressor
new water pump

 

No real advice. Many on this board have gone to 134 and have apparently been very satisfied with the conversion. My experience, however, wasn't so satisfactory. Regardless of how much tweeking was done on the system, on a 90+ degree day, I was still warmish--so much so that when my compressor recently went south, I reconverted to 12. Now? Icicles.

JamesC

 

I did the conversion a couple of years ago right after I got my 'Bird. I'm in Dallas, and mine works great. However, when I first did it, I had the same situation as you.

My suggestion, and what I did on mine, was add another PAG oil and another can (or two) of R-134. I was using the gauges, and it was showing it wasn't "full". Been plenty cool and worked great ever since.

The one difference in what we did was I did not flush mine (it was totally empty to begin with), and I re-used my old compressor and hoses.

Hope this helps. I did the conversion because I wanted to be able to do it myself, but I haven't had to add any freon since the original complete conversion.

Having a black car in Dallas, TX, I feel your pain.....

 

Thanks guys, i appreciate the help. If i do get this thing cold, ill post some updates to try and help anyone else that is cooking out in the heat...

 

I've heard from many sources that r12 and 134a aren't THAT much different in their cooling properties... and if you have a new compressor/drier/orrifice tube... (shrater valve?) then you should be just fine...

my car is the same way, it feels maybe 10 degrees cooler in the car when it's 90+ outside... so I'm actually having everything replaced today, and putting in 134a

 

Before you put any more money into ac parts, get a dual fan setup, and make sure they are BOTH running when the ac is on. That will make a major difference. Also make sure your radiator and condenser coil are clean. Straighten any bent fins and hose out any dirt/crud/obstructions. Also make sure you've got some weatherstripping/foam of some sort around the sides between the radiator and condenser. The idea is to make sure that the fans suck air through the rad AND the condenser, not around it.

Don't waste time changeing your evaporator coil (unless it is leaking), as that is not the bottleneck in this system. It may need a cleaning, but that is probably all it needs. Concentrate your efforts on getting as much heat transfer at the condenser, and your car will get cooler.

 

Thanks for the info
I have a dual fan from ramchargers, and im trying to figure out how to wire it up and mount it. I have a leak somewhere in the system, it has almost completely leaked everything out. I think it may be at the condensor, since the condensor is used. That and theres oil there by the connection, so im thinking its squirting out there. I got a vacuum pump box that you can apparently hook up to an air compressor and my manifold gauges, which i intend to use when i have found the leak to pull a vacuum on the system. There is no space between the radiator and condensor now, i got a much larger condensor off a firebird/transam. I'll post when i have more info.

 

I just bought a new compressor, accumulator/dryer, and a new oriffice tube.

The damned compressor has one connection on the back that requires a thicker seal to make good contact.. so I had to buy a smaller seal and do some rigging of differently-sized seals to get it to hold pressure reliably...

can't friggin' believe the new compressor (intended for MY car,) didn't come with the damned seals... especially since their not the same seals as the stock compressor...

I also replaced the pressure switch on the back of the compressor, hoping that this would cause my fan to come on at idle, so that my ac would blow cold at stop lights... no luck... so I'm still stuck with my manual fan switch...

I guess I'll just cut the pressure switch wires, and wire them into the fan relay....

 

oh yeah, this thing blows friggin cold... it's like 95F outside and it felt like 50F in my car... more than enough for me... sheesh!

it may be way colder, I just know it's enough to make me uncomfortable after a while, and that takes a lot for me.

 

in addition to the bigger fans which should help it out at idle, you may want to try whats called a smart orifice tube, they aren't cheap, around $25.00 or so, but they seem to work quite well when converting from r12 to 134. we use them on some of the conversions we do & most of the time the system seems to cool as good on the road with 134 as what it did with r12.

 

I saw the variable oriffice tube... what's the benefit?

 

benefit is about a 15 degree drop in temps (in my experience)

 

hrm, why is that exactly?

I would have bought that instead, if I had known the improvement was so vast.

 

I put some leak detection dye into the a/c system last night and ran it to check for leaks. I bought a LED flashlight pen and UV goggles and havent found the leak yet. The A/C runs very cold at night, it ices on the drier. I had a setback this week, my Modine alumnium radiator blew a couple pinholes in the aluminum right by one of the plastic tanks. I went to the junkyard and found another two row alumnium radiator with plastic tanks and popped it in. I can run the a/c in 90+ degree weather without overheating the engine so far, around 210-220 degrees the a/c just completly stops putting out any cool air. I'm thinking i have high head pressures, im going to whip out the manifold gauges and figure out how to put that dual fan in. That variable expansion valve sounds like a good idea, i had forgotten about it, someone told me years ago about it....

 

After reading these post I feel really lucky that I converted for $40.00 to 134a, put in two bottles of coolant and had no leaks or anything. My car is very, very cold and the temp. here in Illinois today in 90 degrees. With the leather seats and after teaching school in a hot classroom all day and getting into a cold car will be a nice relief. Whatever you guys have to do to get your car cold, just do it. It's worth it.

 

Don't really know if this applies, but it's very easy to overcharge
r134a. Usually your 36oz r12 system will only need say 32-33oz
to have the same effect. If you put the full 36oz of r134a in your
system, your head pressures will go up just enough to keep from
cooling your car effectively.

 

just put in enough to where you're at the appropriate pressures... I only needed 24oz somehow. plus 6oz oil

 

You can't really go by a formula and just put in x ounces. Every system is different. Part of it depends on how you retrofit. From what I've seen, if you flush a system clean, it will take more refrigerant than if you just dump on top of the old stuff.

The best way is . When I charge a retrofit, I watch 3 things. Pressures, vent temperatures, and evaporator superheat. The only problem with doing it that way is it takes experience to know what you're looking for.

 

Yup, just a general guideline.....the system should be flushed any
time you open it if your are having compressor problems, especially
with a 'black death' compressor like the R4 family. If the system is
properly flushed, you should be able to get within a couple ounces
of your specified capacity.

 

black death?

 

Black death is about the worst way a compressor can die. it can happen when certain compressors go kablooey. I'm quite aware of the r4's reputation for poor reliability, but I had never heard of it having problems with black death.

good article here

 

wow that's a good article,read it guys..Gee that probably explains why my compressor makes so much noise...ouch!!!

 

r4's are just noisy compressors. A perfectly healthy, well cooling r4 can sound like crap even though there's nothing wrong with it.

 

is the r4 what we have in our cars, or is it a brand or what?

 

R4 essentially means radial 4-cylinder, and yes they are quite
suseptible to Black Death. What Black Death consists of is the oil,
refrigerant and fine particles of metal, usually from the swash plate
and other related components, mixed together makes a nasty sludge
that clings to the inside of anything with small passages, such as
condensers, evaporator cores and orifice tubes. Flush solvents
are only marginally effective, and each component must be flushed
both directions (or replaced-preferred).

When our compressors seize, or just when they are extremely old
and well used, you will most likely find the dreaded Black Death.
Another thing to think about, is that accumulators are supposed to
be changed every 4 years.....most people don't, I'm guilty of it
my own darn self. And yes, the R4, even brand-new is a noisy
*****, eclipsed only by the Chrysler RV-2.

 

I checked the pressures with the manifold gauges, i got a reading of 30 PSI low side/ 200PSI high side on max cooling at night around 80deg ambient temp. The compressor makes a racket. I filled with about another half a can and a couple ounces of PAG oil, and checked 40PSI-low/250PSI-high, and a big improvement on vent temps, the reciever definitely sweats now during the day. This is all on the standard electric cooling fan. The compressor noise has decreased quite a bit as well, and i still cannot locate the leak.

Anyone know where the drain for the evaporator coil is, and also how do you clean that thing, its snuggled in there really well.

 

If the compressor is "making a racket", I'd bet my pippy on it being the culprit. Had two compressors blow up on me shortly after they made this sound. From my experience, if the compressor is loud or making a clicking/chirping sound, it's going south. And if it's spinning but the A/C is not cold (although full), that's another sign.

Hope this helps.
Lou

 

If the compressor pops i hope it does before the 2 year warranty is up, i bought it new from carquest. I think the noise was partly due to it being low on charge since its leaking from somewhere. The compressor is much quieter now sometimes i cant tell its on anymore. The R4 compressor i bought also has an upgraded design, and the stock belt didnt fit so i bought number 7555 from oreillys that fit well.
The charge i put in was a full can, i just weighed the can right now, and it was almost empty so i dumped the rest in. If you have a noisey one, make sure you have enough oil and a big enough charge.
Most of the noise is when the RPM's are lower than about 750, i think it hits the resonance frequency of the gas column that it is pumping and it starts to vibrate. I am thinking of getting rubber bushings and smoosh them under some of the bolts and see if that dampens it. It is interesting they didnt put a muffler on this design. I also noticed that the better i make the engine run, the less of a nuisance driving the compressor is.
I read a website where this guy took the R4 off and put a variable compressor on....I need to look up that website again.

 

you can always take it back in before the warranty is up and tell them it's broken...

problem solved.

 

I've got 3 r4's that all make that noise. 2 retrofitted to R134a, and one on it's original R12. Just above idle speed, the noise goes away. That's just a normal R4 compressor. If it was a noise that was indicative of a problem, it usually won't go away with increased rpm.

If you want your r4 quieter, there's a GM TSB for it. Basically it's just one 1/2" steel brace. I put it on my car, and the noise was noticeably reduced, but still not gone.

Have you worked on a system with a variable compressor?
They're a nuisance. I'd recommend an R4 over a V5 anyday.

 

I just put in a new(new $229) compressor from Autozone, and at idle, it causes my tensioner (brand new, mechanic installed, and replaced just in case,) to bounce like crazy! if I rev it up, the vibrations go away, but at idle it sounds like someone is banging a hammer under my hood.

how hard should the compressor be to turn by hand? the one I replaced was easy to turn by hand, and the new one, before I had it put on, was very tough...

also, has anyone noticed that the 'NEW' compressors don't match up perfectly? the input/output on that back of the compressor are offset slightly, (as in, you need different thickness of seals for the compressor to work with the piping.) If these are OEM replacements, why do I need a special set of seals that don't come with the compressor to make it work on my car?

btw, NAPA auto parts is the ONLY auto store that I've found that carries them... not Advance, orielly's, or AutoZone... I didn't check any hole-in-the-wall places though...

 

did you oil the compressor before you installed it? It sounds like your compressor is too tight.

 

black89ws6
Do you have a tsb# or a pn# for that brace? Mine R4 compressor is running really smoothly now, i think its the new design they did on the clutch/pulley, its much flatter and wider. It still transmits vibration into the car, but now its less noticeable, i forget its on sometimes when im driving around. At 30PSI on the low side it makes a big racket, at 40PSI low side its running really smoothly on mine, and its blowing air out the vents now.

We have mostly chevy and fords, so those are the ones i am familiar with (most of them have R4 compressors anyhow). I had just seen a website that the guy said that variable compressors were smoother than R4s, but i like the way mine is running now.

ScrapMaker
I think i paid $150 for a new R4 from carquest, i called every parts store in town, even the a/c places. I ran through a couple remans from autozone that crapped out. I had everything installed by a mechanic to try and avoid a leak. The a/c hoses are new, and i see what you are talking about on the back of the compressor, its tilted at angle and its compressing the seals differently. Mine came with new seals in the box, it seems to be holding.

 

damnit! for $229 NEW I should get those damn seals!

arg... maybe I should just return the whole lot and get it from carquest... or somewhere else.

also I'm gonna toss in a variable oriffice tube this time...

I was told that I shouldn't have to replace the dryer again... what do you guys think? When it was installed the first time, there was no vacuum pulled on the system, so there's no telling how much moisture it's absorbed... but I was still assured it had plenty of storage and we should not have a problem...

I still think AutoZone should PAY for a new dryer... hell, I think they should have to pay for the labor too, but I know I can't get that back... lame

 

Yeah, good luck making them pay for anything.
I installed a compressor from AutoZone and two weeks later it leaked out around the clutch. Faulty compressor. I exchanged it but they refused to even reimburse me for (or give me new) R134 that I lost, of course.

Nobody's responsible for anything these days, get used to it.

 

I'm afraid not. I read about it at alldatadiy.com, but my supscription there has expired. I printed out a copy last summer when I put those parts on, but I can't find it. I don't have much time to look right now, but if I get more time tonight or tomorrow, I'll see if I can find it.

I don't think it would apply to your 86. It applied to cars with the serpentine belt accessory drive. That's not to say there isn't one for them as well, but I don't think this one will help.

 

Scrapmaker
Did you have the system flushed before you put the compressor on? When i bought the compressor from carquest, the bare minimum to get a warranty on it was a new orifice tube, accumulator and flush and vacuum. The flushing cleans out all the junk from the small spaces so you dont end up with restrictions or a failed compressor. The orifice tube acts like a screen and the accumulator is good usually for 2 years. You need to have a vacuum pulled to boil off any moisture in the system before you charge it.

If it were me (and believe me i feel your pain i was there a few months ago). I bought the orifice tube, NEW compressor, accumulator, and since the hoses were almost older than me, i bought new hoses too. $220 for compressor/accumulator/orifice tube/$40 for bigger used condensor off a firebird/$100 for mechanic to do all that crap/$150 for new hoses from dealer.

Also, it sounds like you need to charge your system with oil, and check the pressures, it may be low on refrigerant. I think* when you first buy a compressor, you pour in an ounce of oil directly into the compressor, and you also add oil to the accumulator before putting it on, i even heard of a mechanic adding oil to the condensor. Of course too much isnt good either, but if its incredibly hard to turn you need to check to make sure its got oil, and check the belt tension too. I had to buy a different belt when i got my new compressor since the clutch and pulley were different. Good luck

 

The mechanic that installed my compressor put about 5oz of oil in the compressor, turned it about 10 times by hand, and installed it...

we just used air pressure to blow the system out... not a vacuum...

once you open the system to the atmosphere, all of the r12 will evaporate... blowing the system out is mostly for the remaining oil in the lines...

where would all this moisture be? it should have been stored in the accumulator... not in the lines... right?

 

This=bad.

The vacuum is for 2 purposes. Air in a refrigeration system is noncondensable, and will reduce system performance noticeably. The system also needs to be completely devoid of moisture (doubly so if not R12). You want all the moisture out...even water vapor.

 

Yeah what he said

Also to go into more detail water vapor in the system is detrimental to the oil that needs to circulate and keep the compressor running properly. The reason you pull a vacuum is two fold: you suck out all the air in the system and if your system can hold a "vacuum" then there are no leaks. The second is that to boil water, you have to heat it to 212 degrees F in atmospheric pressure. Remember that you cannot see steam, what you "see" is water vapor condensing in the cooler air.

But water boils at a lower temperature in a vacuum and the water vapor (you cant really see it in air) will boil and get sucked out. The system will now be "empty" and you stick only whats supposed to be in the lines back in, i.e. the appropriate oil and refrigerant.

And yes R12 has a very low boiling point -27 degrees F, -15 degrees F for R134A in atmospheric pressure it will boil but the moisture in the lines will NOT boil in atmospheric pressure. The accumulator stores excess refrigerant and has a dessicant that attracts moisture. Moisture will condense on anything that is cooler than the surrounding air. Like when you take a shower the moisture hits the colder mirror and condenses on the mirror, when the car is turned off and the system cools the moisture in the lines will condense.

This a thermodynamics posting!

 

I have a question now.....Has anyone modified the intake under the dash on the passenger side for the a/c? I noticed that cover pops down and the evaporater is right there apparently. You can hear the blower going and feel the hot air going into that intake, but it has a small opening/grill where right next to the light where it pulls air in from cabin. My a/c blows pretty weak, its ok when i am by myself because i can hog the vents. Also anyone know where to get sealing kits?

 

Right on, but for one thing. Because of the pressures in the system, the system does not have to be cool for the water to condense in it. If the system has water vapor, that vapor will condense when the system is charged, and it will stay liquid and circulate through the system that way.

 

so... do you just take a mity-vac to the system, or what? I'm trying to get this done without going to a shop...

also, after you pull the vacuum... right after you pull the source for the vacuum off of the lines, won't you lose the vacuum, and suck back in AIR (moisture) ? or do you leave the vacuum in the system, (always bad for seals that aren't meant for it,) and just use the vacuum to help suck in the refridgerant?

that last way would be impossible, because you need to phsyically pour oil into the compressor before you install it... how can you hook up the compressor and pull a vacuum on it if there is oil in it? Won't the oil try to come out, or will it not boil?

If the oil doesn't boil, then that means that pulling a vacuum won't get the old oil out anyways, and you'll need to flush the system with some sort of liquid cleaner...

maybe if someone elaborated more on the actual vacuum portion of the procedure, I could understand it a bit better...

Thanks

 

Scrapmaker I just finished doing this last nite. See post "AC Evacuation" I rented the vacum AND gauges from Autozone it has the instructions on it. Basically after the vacum has been pulled for about 45 mins, you close the valves on the gauges, turn off vacum source disconnect hose from vacum source and connect it to can of refrigerant, now open valve on the low gauge, pierce can of refrigerant and it will get sucked up through that middle hose.
I too was very confused not ever having done it before, but man it was really easy.
The oil for the compressor is poured in and then it is mounted on the vehicle, then attach the hose block on the back of it. You pull the vacum on the drier not the compressor, the compressor is hooked up to the drier by the hoses.
Hope this helps and not confuses you even more.

 

how much was it to rent that vacuum pump? I'm wondering if it's worth the extra effort, because my A/C blows really cold, just the compressor is screwed up...

I'm thinking of putting in the variable oriffice tube as well...

if you think about it, wouldn't any moisture in the system just go to the accumulator and be absorbed?

 

If compressor is screwed up and you replace it you will have to vacum the system.
You need to get all that air out of the system once you take the hoses off the back of the compressor.
Vacum was $200 deposit and gauges $100
I don't think you can use a little Mity-Vac on it.

 

Scrapmaker
When you pull a vacuum on the system you are also checking for leaks, if the system wont hold a vacuum then it is leaking air IN. Yes you are going to leave the system in a vacuum, which is lower than atmospheric pressure. If you think about the o-rings they are sealing at 30-40 PSI already on the low side and 200-300 PSI on the high side, thats higher than atmospheric pressure and they hold that. Yes you are right you have to flush the system with an A/C flush kit to get the old stuff out, but you do that before you pull a vacuum.

I believe you are supposed to pull at least 30PSI, which you arent going to get with a Mity-vac. Also the vacuum pumps pull vacuum within microns, thats why they cost around $400. When you are ready to disconnect the vacuum source, you close off the VALVES. Think of it like a shutoff valve. The manifolds have valves on the connection at the low and high side schraeder fittings, and then they have valves at the guages. There is a middle hose that is used for charging and evacuation as well, depending on how you open the valves.

Zap89
Thanks for the info, i didnt know autozone rented out the vacuum pumps, thats good information. I've never pulled a vacuum on the system yet, but instead of taking it to a mechanic im going to do it myself next time. I know how to use the manifold now and how to charge the system.

 

dang...

 

5oz of oil isn't enough, the system will cool better with less oil, but the compressor won't last.

air in the system will cause poor cooling & also cause the high side pressure to be very high which can damage the compressor.
moisture can freeze in the system & cause poor or no cooling along with causing damage to the components.
as was said, blowing it out with air alone won't remove much oil or trash from the system,... use a flush.
without flushing & evacuating, it can take days for a r12 system to out gas all of the r12 from the old oil.
an accumulator won't hold much moisture, on a high humidity day without evacuating, the system can hold enough moist air to for the most part load up the drying agent.

the longer a vacuum is pulled, the better. on my car i pull over night, on a customer's car they normally can't leave their car over night, but i still like pull for at least 2 hours.
when evacuating, the warmer the temp is the better. with the gages & vacuum pump hooked up & running, start the motor up & let it run for a while with the heater on high with the doors closed & the hood down. the extra heat will lower the amount of vacuum it takes to boil the water out of the system.

 

hey DENN_SHAH
Any inside hints on getting this A/C colder?
I know you said dual fans, i'm waiting for the harness adapter so i can put the 140A CS144 in my car, so i can power those dual fans. I should have put the variable orifice tube in, but right now the system is charged and i dont know how to evacuate it into a cannister. I guess i could buy a cannister and rent a vacuum pump and then do it that way. The physically larger condenser seems to be doing a better job than the little stock unit that came with the car. I'm going to buy insulation and insulate all the exposed hoses on the a/c. It seems it would help if i could get this system to blow out the cold air harder, the 95 mustang we have blasts you with cold air.