R12 to R134a AC conversion

Post by **nnkfws333** » Mon Apr 28, 2003 5:53 am

Has anyone here that has a S13 that has done a conversion? Ive read on the 240sx.org sight the processes but has anyone actually did it? Im wondering how the install process works and the outcome if it was worth it or not. Any dangers to this as well? Im thinking about this...any thoughts?

Post by **PalmerWMD** » Mon Apr 28, 2003 5:53 am

I dont own an S13, but I can tell you from experience that the converted AC's are often noticably less powerful unless you replace the<entire > system ( compressor, evaporator ect not just change the gas+oil+dryer).

Yes the R12 cost more but if u dont have a leak, really not an issue..

Fred...

Post by **yellow_jacket** » Mon Apr 28, 2003 5:53 am

Like he said, if you don't have a leak I wouldn't do it. To do it properly you really have to flush the entire system. I wouldn't even consider doing it unless you are going to take every seal out and run flush through the whole thing.

Some cars do have more of a problem with it than others due to a smaller evaporator.

Almost always the converted systems will blow a little warmer, especially while you are stopped.

Post by **trpower7** » Mon Apr 28, 2003 5:53 am

To do a full, good conversion you have to replace every seal and gasket as yellow said, and make sure every bit of that old coolant is out. It also will blow slightly warmer. Unless you have a pretty hefty leak I'd stick with R12, the cost just isn't worth it.....

Post by **Nismo1182** » Mon Apr 28, 2003 5:53 am

Mine has a leak, its 100% empty now. It used to blow cold a few months back. R12 is very expensive but i got the hook up on a tank for free. But if my system leaks it back out its rather pointless filling it back up with the same R12. I dont think my friend would like that. I was thinking of just getting that kit they sell at autozone to conver it to R134. Or maybe taking it to a shop and have them redo the whole system. Anyone have a rough idea of cost for this?

Post by **nnkfws333** » Mon Apr 28, 2003 5:53 am

Any ideas for the easiest way to check for a leak? I mean I think Im low on R12 (I got a couple of cans) because I see bubbles in the evaporator glass while the air is blowing but does R12 just disappear or does it leak in order for it to be low. Also anyone ever replace the evaporator? Is it swappable from a S14 to a S13?Thanks for the responses its been helping me out a lot. You guys Rock!

Post by **180fan** » Mon Apr 28, 2003 5:53 am

UV detector. You put a small amount of gaseous dye into your system, and put the light to it. If you see a neon colored gas being emitted from your system, you've found your leak. I think you can find stuff like that in your AC Coolant and recharge section at an auto parts store.

Post by **sil80drifter** » Mon Apr 28, 2003 5:53 am

I just removed my AC yesterday. Still have to get the AC radiator out, but total weight savings are about 50lbs. I never use mine anyway, and it was empty, with leaks and a broken AC radiator fan. It'd cost too much to repair, last time I asked a shop. It did feel really good to take all the crap out though. Like working out and noticing you're losing weight, but for your car.

sil80

Post by **nnkfws333** » Mon Apr 28, 2003 5:53 am

Actually I think I found out the problem but have no clue to how going about this. My AC doesnt click in. I Mean my rpm's dont go up and my condensor fan wont even turn on. It does sometimes and it doesnt at other times. Any ideas? heh its starting to bake here in Florida and I do 60-100 mile driving everyday.

Post by **240_Keyy** » Mon Apr 28, 2003 5:53 am

Well I was just going to hook my SR compressor and condenser and stuff up to my car, but I guess that won't work?

Oh well, fook it, I will just take the AC out, it has never worked anyway...

Post by **yellow_jacket** » Mon Apr 28, 2003 5:53 am

It could be various things. Dash control unit, low pressure switch, faulty a/c clutch. You will just have to go through and check them out.

Post by **nnkfws333** » Mon Apr 28, 2003 5:53 am

Thanks Yellow Jacket but any clues on how I can check those?I can just buy another dash control unit at a junkyard to see if it works but how about the others (low pressure switch, AC clutch)? Do you mean the AC clutch meaning the clutch fan. I hooked up my fan to the battery and it turned on so I know its not that. My only guess would be the low pressure switch.Where are they even located?

Ive been researching and looking at other forums and Ive gotten no way other than you guys helping me out.

Post by **DAEDALUS** » Mon Apr 28, 2003 5:53 am

180fan wrote:UV detector. You put a small amount of gaseous dye into your system, and put the light to it. If you see a neon colored gas being emitted from your system, you've found your leak. I think you can find stuff like that in your AC Coolant and recharge section at an auto parts store.

Actually it's the oil that leaks out with the freon that will be glowing under the UV. There usually isn't enough gas to be visible (better not be). But without the UV, you can look for grimy areas near the AC line junctions. Oil traps dirt. It's hard to find stuff compatible with R-12 systems since they're far less common and since you need to be EPA-certified to perform any R-12 repairs.

Get a multimeter and a manual and check things one at a time. Start at the compressor and work your way up. See if there's voltage to the compressor with the AC switch on. Then check the pressure switches for continuity from the connectors. If there's a temp switch, check it too. Then check the relay to make sure it's working fine by supplying a voltage to the right terminals and checking continuity across the other 2 before and after. If everything checks out fine, and the compressor isn't engaging, then you probably have a bad compressor.

Post by **nnkfws333** » Mon Apr 28, 2003 5:53 am

Would a bad compressor cause the condensor fan not to come on even though I tested the fan to be working?

Post by **DAEDALUS** » Mon Apr 28, 2003 5:53 am

Sure...condenser fans usually have a pressure or a temp switch that turns them on, and sometimes both. The pressure switch would be on the high-side, so if the compressor isn't working right, there wouldn't be a pressure increase.

Post by **Exar-Kun** » Mon Apr 28, 2003 5:53 am

well, I say if your A/C stops working, just take it out......-chet

Post by **Nismo1182** » Mon Apr 28, 2003 5:53 am

Exar-Kun wrote:well, I say if your A/C stops working, just take it out......-chet

nah, i cant take this FL heat anymore. Plus when it rains, like today, it gets all hot and foggy inside. The girls dont like that, the freaky ones maybe, but not the ones i know

Post by **nnkfws333** » Mon Apr 28, 2003 5:53 am

hahaahh I feel for you right now Nismo1182 and its only gonna get hotter so I dont know hopefully tomorrow I can check to see what is wrong. It worked fine for 15 min then it stopped. *sigh* I hate this.

Post by **Nismo1182** » Mon Apr 28, 2003 5:53 am

My system is completely empty, i checked on sunday. Going to try to get some R12 from my friend. It works for the first 4 months I had the car. I know for sure theres a leak. Just gotta find out where.

And as for your question before,

the pressure switch is on the filter thing on the passenger side by the radiator. Right behind it. I had a little looking glass thing to check your system too. The AC clutch is on the compressor itself. Its what engages the compressor on and off when you turn the a/c on or off.

Post by **nnkfws333** » Mon Apr 28, 2003 5:53 am

well hopefully someone can maybe give some advice here but I replaced the condensor and drier and Im in the same situation. Works for 5-10 min and then the AC is no longer cold. Blows out air but it isnt cold and the compressor is no longer on. I have no idea what I can check for. I dont want to buy a new compressor to find out that that wasn't the problem. I can turn the compressor by hand but one problem is I don't feel the compressor kick on when I turn the AC on and the air is cold and Im full of R12 freon.

Post by **DAEDALUS** » Mon Apr 28, 2003 5:53 am

DAEDALUS wrote:Get a multimeter and a manual and check things one at a time. Start at the compressor and work your way up. See if there's voltage to the compressor with the AC switch on. Then check the pressure switches for continuity from the connectors. If there's a temp switch, check it too. Then check the relay to make sure it's working fine by supplying a voltage to the right terminals and checking continuity across the other 2 before and after. If everything checks out fine, and the compressor isn't engaging, then you probably have a bad compressor.

There are 3 paths to follow: Take it to a shop, do some diagnosis on your own, or start blindly throwing parts at the car. A good tech can tell you from experience what common failures are, but there's no way for anyone to know exactly what the problem is from the symptoms alone. As an alternative to the steps listed, you can try manually "hotwiring" the compressor by supplying a voltage to the clutch. If it kicks on and blows cold, then you know you have a bad switch/relay somewhere.

Post by **nnkfws333** » Mon Apr 28, 2003 5:53 am

Yeah I was thinking about doing the hotwire test. Aren't there only 2 wires coming out of the compressor and they hook into a fuse box? I was thinking cutting that wire and hooking it up to the battery and seeing how long it works.

Post by **nnkfws333** » Mon Apr 28, 2003 5:53 am

Alright sorry guys to bring back the posts but I think I might be getting somewhere. Well after getting an SR Swap, we fiddled around with the AC system. We are using the SR compressor and converted it to R134A and we manually turned it on by using the wire trick in the relay box (hook up 3 and 5) and it blew cold air!!! Well from what we notice that relay isnt getting any ground at all! From what I heard there is a switching ground that turns on when you turn on the AC and its not switching to ground. So we hooked it up to a good ground source so it worked and the compressor turned on but of course my AC fan wasn't on. So I Guess my question is does anyone know how to fix that dam switching ground? I don't really care about the AC fan I can hook up an thermostat or something. Any help this would greatly be beneficial!?

BTW - already put new Relay's and fuses and new AC controller just in case.

Post by **NISTECH** » Mon Apr 28, 2003 5:53 am

When I get back to work on monday I will look up your circuit diag and see what controls the ground on your year. Newer cars its the ECM bot on older ones I believe it is controled by 2 devices. the control unit A/C switch is the supplier of the ground but the pressure switch is the desicion maker that either allows the circuit to complete or not based on A/C system pressure. If the pressure is to low or to high[depends on design] it will not close the circuit. I will post as soon as I know 100% which system you have.

Post by **nnkfws333** » Mon Apr 28, 2003 5:53 am

Hey Nistech, not sure if you been busy but just wondering if you got any more info? Thanks.

Post by **xxtrizz** » Mon Apr 28, 2003 5:53 am

OK about the condensor fan...... you should probably have a sensor running from it. The fan will not turn on unless the sensor reads a high temperature. Therfore your fan will not turn on if it has only been running for 15 minutes. I believe the temperature for the condesor has to be in the high 100's or mid 100's.

Your course of aciton about the fan is the way. Dont worry about it.

I installed a fresh A/C in mine. The book stipulates that the A/C light for the interior does not turn on unless the system has refrigerant, and the condensor fan does not turn on unless at high temperature. Just two things you should know. I about crapped my pants when I read both of those.

Post by **xxtrizz** » Mon Apr 28, 2003 5:53 am

Oh and about converting it Im sure you did everything fine. But I was curious as to wether you changed out the evaporator unit? This would include the expansion valve.

this explanation came from an earlier post I made.::this is a factory r134a conversion from nissan::

The upgraded r134a kit usually includes the NEW expansion valve which is located in the Evaporator usually reffered to as the evaporator core the expansion valve is a necessity when changing to r134a. Also it should include the r134a fitments for "valves" on the A/C lines. Last but not least there should be a completely new Accumulator the accumulator looks like a shiny metallic casing on the right hand side of the battery cage bolted up to the inner walls of the bay. This is also a important replacement part for r134a fitment.

That was about it the only other thing that I didnt mention because I dont know about your compressor was a bronze bolt that goes on either the high or low side of the compressor line that has measurements in gravity. I had to change that also.

Post by **NISTECH** » Mon Apr 28, 2003 5:53 am

nnkfws333 wrote:Hey Nistech, not sure if you been busy but just wondering if you got any more info? Thanks.

Sorry dude . I dropped the ball on ya. I found my notes here on my desk they got lost in the shuffle of paper work..This happens from time to time since I try to answer so many posts. I will stick it to my forhead tonight and look it up tomorrow at work.. again I appoligize.

Scott

Post by **NISTECH** » Mon Apr 28, 2003 5:53 am

Apparently your car has 2 different options for heater controls. is it all push button style or is it slide lever style.. I have both diagrams but need to know which one you have.

Post by **nnkfws333** » Mon Apr 28, 2003 5:53 am

Mine is the slider bar to change cold to hot...I hope thats what your asking.

R12 to R134a AC conversion

R12 to R134a AC conversion

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