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Topic: A/C Restoration - R12 vs R134A, etc (Read 2587 times) previous topic - next topic

A/C Restoration - R12 vs R134A, etc

Let me preface this - I know nothing about A/C!  Also, I apologize if there's already a post about this, but I can't figure out how to use the search function on this site for the life of me.

My 87 V8 Cougar's AC doesn't work - started out as a slow leak and then turned into an issue where it wouldn't keep a charge more than a few months.  It got to be a pain, and I just haven't had A/C for a few years now.  I would like to get it back up and running, and I'm planning on doing a total system replacement so I don't have to worry about it again in awhile.  I've run into a couple questions I was hoping someone could help me with;

I've found that you can fairly inexpensively replace all the parts of our cars' A/C with Rock Auto parts, which is where I'm currently leaning.  However, I've been told that our cars are "R12", which is now hard to get with the newer systems using R134A.  If I use these parts, is my system still an R12 system?  Is there a way to convert the system? 

I found that LMR.com has a total replacement system designed for a mustang V8 that also claims to convert it to the R134A coolant.  However, I've noticed that this system's coolant return line from the compressor to the condenser runs over the engine, past the distributor cap - while mine runs to the right of the engine and then down under it.  The compressor also seems to be at a  different angle on the mustangs.  Has anyone tried to use one of these systems in our cars, and is it worth it?

Thanks - hope I don't sound like too much of a noob!

A/C Restoration - R12 vs R134A, etc

Reply #1 –
All things being equal, if your current system was okay, you technically could switch over to R-134 with the system fully evacuated and the old oil sucked out. But if you’re replacing things anyway, you can still convert that to the newer system with an R-134 retrofit kit. Not terribly difficult...just have to be sure the new compressor is okay with either refrigerant.

For the a/c line you’re referring to, you could use the Mustang upper line, it should fit well. Our cars had a 93” belt with a/c, the Mustang was 91.5”, and that was due to the angle of the a/c bracket as you’ve noticed. I don’t know why our cars got the different line. I used the Mustang line on my Cougar with no problem. However...if you want to be technically correct then you can get a new Cougar line just for that part, and still run R-134 with zero issues.

A/C Restoration - R12 vs R134A, etc

Reply #3 –
R-12 will work a little better on hot days in stop-and-go traffic. However, you can't buy (unless you find NOS) liquid lines with R-12 sized orifice tubes. I'd go with R-134a. I'd replace the py tube/fin condenser that it came with to something better (piccolo or parallel flow). The LMR kits come with them.

Blow the old oil out of the evaporator. Old oil displaces volume and decreases system performance.

A/C Restoration - R12 vs R134A, etc

Reply #4 –
Thanks, Jeremy.  I found the evaporator on Rockauto, but it's not included in the LMR kit.  I can't see this in the engine compartment - I'm assuming it's behind the firewall, on the other side of the acspoogeulator?  If so, I'm guessing it's not easily accessible, which is probably why you're recommending to "blow it out" vs. replace it?

A/C Restoration - R12 vs R134A, etc

Reply #5 –
Unless it's leaking or your compressor grenaded, there's no need to ever replace your evaporator.

It's a pain to replace.

I use compressed air and chlorinated brake parts cleaner to blow out the evaporator. Don't use mineral spirits, as it leaves a residue behind.

A/C Restoration - R12 vs R134A, etc

Reply #6 –
SN-95 condensers fit and are optimized for R-134a.  Replace all the black o-rings with green ones.  Replace the orifice tube with the same color, but when it's on the machine and charged (15% less R-134a than the labeled R-12 capacity), you'll want to adjust the clutch cycling switch on the acspoogeulator until it engages the clutch until 28 or 30 psi on the low side gauge (blue) before it releases. There is a screw down in the connector on the switch to do this with, I like 1/4 turn increments.

A/C Restoration - R12 vs R134A, etc

Reply #7 –
Quote from: TheFoeYouKnow;465324
SN-95 condensers fit and are optimized for R-134a.  Replace all the black o-rings with green ones.  Replace the orifice tube with the same color, but when it's on the machine and charged (15% less R-134a than the labeled R-12 capacity), you'll want to adjust the clutch cycling switch on the acspoogeulator until it engages the clutch until 28 or 30 psi on the low side gauge (blue) before it releases. There is a screw down in the connector on the switch to do this with, I like 1/4 turn increments.
Putting in an SN95 condenser requires cutting of the radiator support and custom mounting brackets. Just use the improved condensers and stick with the stock brackets. Not worth the trouble in my opinion.

A/C Restoration - R12 vs R134A, etc

Reply #9 –
Have any pictures? I put in an SN95 condenser, although it's been so long I've forgotten what year! Maybe a '98 Cobra? They definitely don't fit w/o mods.

'95 Mustang condenser has a 16.25"x29.375" core. https://www.rockauto.com/en/moreinfo.php?pk=3611280&cc=1140231&jsn=602
'87 Thunderbird condenser has a 14"x22" core. https://www.rockauto.com/en/moreinfo.php?pk=3612282&cc=1134188&jsn=480

Don't see how you can fit one in like OEM when it's 2.25" taller and 7.325" wider.

Found a picture of my '98 Cobra condenser in my '87.http://www.griffshp.com/belchja/pics/condenser/sn95cond_050_crop.jpg

A/C Restoration - R12 vs R134A, etc

Reply #10 –
I'm not taking the front of my shiznit off so you can say you don't think my condenser looks like an sn-95 condenser. You'll have to take my word for it or move on.

A/C Restoration - R12 vs R134A, etc

Reply #11 –
I'm genuinely curious how a condenser that is 2" taller and 7" wider and drop into the same bracket location.

Edit:
Let's be real. You can't.

http://forums.corral.net/forums/general-mustang-tech/293293-those-you-wanting-install-sn95-condenser-79-93-a.html
http://forums.corral.net/forums/general-mustang-tech/1105935-1994-condenser-1987-1993-stang.html
http://www.corner-carvers.com/forums/showthread.php?t=26766&highlight=sn95+condenser

A/C Restoration - R12 vs R134A, etc

Reply #12 –
Now that I'm home and looking at it, I moved the brackets, but nothing had to be cut.  The upper brackets are both moved outward, the lower are down and outward.  I didn't say it popped right in like a direct swap, and I didn't say the bracket locations were the same, I said it fits like OE.  OE means using my brackets, maintaining position relative to the radiator, and generally riding in the same position as on the donor car.  I moved brackets, for which I had to make new holes; nothing more.  I don't know why you had to cut and I didn't, I only know that 8 years ago, the last time I touched it, it was a fairly minor mod to move the brackets.

A/C Restoration - R12 vs R134A, etc

Reply #13 –
Quote from: TheFoeYouKnow;465324
SN-95 condensers fit and are optimized for R-134a.  Replace all the black o-rings with green ones.  Replace the orifice tube with the same color, but when it's on the machine and charged (15% less R-134a than the labeled R-12 capacity), you'll want to adjust the clutch cycling switch on the acspoogeulator until it engages the clutch until 28 or 30 psi on the low side gauge (blue) before it releases. There is a screw down in the connector on the switch to do this with, I like 1/4 turn increments.


This seems spot on.  I have a 88 Cougar 5.0  All stock 88 stuff, new cycling switch and adjusted,  Vacuumed down and refilled. Changed nothing else, no leaks, not recharged in 6 years.  AC blows very cold and keeps very cool.  Mine is a black car in KS summers.  If I had to do it again, I would do just what He said above.  Fortunately mine worked great stock, just as was.
Mike

A/C Restoration - R12 vs R134A, etc

Reply #14 –
Ah, I took fits like OE as fits in the same as OE.

I had to cut because I used existing holes and made ghetto brackets for it. Drilling new holes to lower the condenser would eliminate cutting the upper radiator support. Two methods to achieve the same end - although I think drilling new holes is the better way to go. At the time, I hadn't found anybody who had done it and the internets yet, so I was on my own for the install - and I don't do well with original thoughts!