A/C Dead, options?

[kishy]

I currently have no vehicles with working A/C, and I've seen some discussion here lately that makes me think we have A/C-knowledgeable folks here.

The Town Car A/C did work up to perhaps 6 months ago, and then went to the rapid clutch cycling symptom, which I believe indicates low refrigerant = a leak somewhere. When that happened, I unplugged the clutch to prevent it running unnecessarily when using A/C vent modes. The system is still R12. I'd like to look at my options to repair and fill it with R134A, but I lack certain tools and knowledge needed to do the full job.

What I'd like to do is:

• Have a shop empty the R12, so I can disassemble and work on it without venting it (don't care about legality, R12 is legitimately damaging to the environment and I don't want to vent it on that basis)
• Have a shop leak-test it and indicate to me where the trouble spots are.
• If shop recommends it, have them flush the system.
• Once leak test information is known, I'll take the car home, disassemble, replace O-rings, hoses, orifice tube etc
• Bring new drier with me, install it at the shop or just have them do it (to minimize time the drier spends unsealed)
• Have shop vacuum and fill system with R134A and lubricant as appropriate.

I understand our cars have FS-6 compressors which are considered pretty reliable and adequate for R134A conversion, correct? I also understand they aren't prone to "black death"?

I understand that since not all components of the system are being replaced, some of the old oil will remain, so I need to pay attention to the type of oil used with the new refrigerant to avoid reactions between the old and new oils. What I have gathered so far is that the existing system uses a mineral oil, a completely new R134A system uses PAG-42 oil, but because some mineral oil will remain, I should use ester oil. Can someone please confirm this?

Also, I do tend to like doing stuff myself, so I would love to have the knowledge to do this myself. Is it possible to pull off a successful vacuum and charge at home, and if so, what tools do I need? I figure 134A conversion fittings (have them), manifold gauge set (don't have it), vacuum pump (don't have one sufficient for this use), and of course the R134A itself. Anything I'm overlooking?

Is it possible that I could do the leak testing myself? What would be involved with doing that?

The evaporator is of course a pain to access, so I'd rather not need to change it. How likely is it that it would need to be replaced? Is leakage the only true failure they can have?

The condenser is not available new for MY 85 and down Panthers...but it is for 86 and up. Same questions as for the evaporator, should I expect to need to replace it? And what makes the 86+ different?

Not in any sort of rush with this, though I am quite uncomfortable without it, I don't want to rush to a solution and find out later I missed something.

[DerekTheGreat]

My Town Car's A/C was dead when I got it. Old man never used it. Old compressor worked for about a year once I had the conversion done and then it shit the bed or more specifically, the gasket in the middle of the compressor. Since yours was working I think the conversion will go without a hitch for you. All they did for me was put the fittings on over the existing ones, suck out the old stuff, swap in a new drier/accumulator and refill with pag oil & 134a. Has been good ever since with the new compressor. I highly doubt you'll have to deal with leaks within the evaporator, seems the O-rings are where they leak on the manifold attached to the compressor. If that happens the goo with stop-leak works well. Firebird had that problem until some of that juice was added and I haven't had to add any refrigerant to that in over 5 or 6 years now. Before, it needed a can a year.

[kishy]

I hesitate to consider stop-leak as an option, since in my mind an orifice tube is going to get sealed up by stop-leak. But, maybe it's more viable than I think.

I don't mind shelling out the cash for the compressor if it would be the smart thing to do. That being said, an A/C shop I called said they would try to use what's there to begin with, so there's that. It did work though, and when it worked, it wasn't particularly noisy.

My thinking in pulling the clutch connector was to hopefully "preserve" the state of the compressor and avoid running it low on refrigerant, because low on refrigerant would presumably also mean poor oil circulation. Hopefully that was the right choice on my part.

[DerekTheGreat]

Firebird is still choochin' strong, that system has never been opened up to change the drier or anything like that either. Car gets cold... I think that stopleak stuff reacts with oxygen or some other science like explanation. I just put two 12oz cans in our K1500 (Yesterday ~1PM) and by 5:30 this morning it was low enough to the point the compressor was cycling rapidly. You can see it leaking right behind the pulley, bubbles everywhere. Sad face. Oh well, it's noisy anyway.

I think that was a good call, I'd do the same. The fact your system still has pressure and was working is a very good thing IMO, means nothing else got in.

[sly]

My 88 is still rocking the original compressor. It's been converted to 134a. You have to evacuate and flush the system and clean the old oil out as much as possible. Then go back with ester oil unless replacing everything. Ester oil is compatible with the residual R-12 and won't create acids like PAG oil will. The rule of thumb is 2 oz each in the evap, accumulator/dryer, condenser, and compressor. Then put it all back together with new o-rings and pump it down as close as you can get to 30inHg (under 100 microns preferably) and then charge it up with clean 134a and have a nice day. The real trick is finding good refit fittings for the high and low side connections.

[Tiggie]

Sounds like you've done your homework.

Been researching your question on the condenser, and why it's different for pre-86. No luck. I'd say take a look vs your 91 and see what you can see. I am betting, worse come to worse, you could swap to the later system as a whole using the later lines if needed.

I see no reason to replace evaporator or condenser in this case unless you know they are damaged (leaking or condenser fin damage). Now if mice had taken up residence in your HVAC box like my '68, then that may be a different story.

There are some old stock of your condenser, Motorcraft PN YJ-217 is the one you'd need if it turns out there is damage and not converting to a newer system. Not cheap but available on eBay currently. Our cars used to be cheap junkyard parts, now I'm starting to see they are needing expensive/rare/unavailable NOS parts.

[gadget73]

Compressor should be fine. Most of the time when they get leaky its one of any number of O ring seals. Frankly I'd just change all of them, it'll save you a lot of headaches chasing the specific one that is leaking today and hoping that a different one won't leak tomorrow. O ring assortments are cheap and its not that hard to do. Would be worth flushing it to get the old oil out too. R12 ran mineral oil, which is not compatible with R134A. Ester oil won't react badly with the mineral, but it won't really mix with it either and you'll end up with pockets of oil laying about that don't help system performance any. Change the drier, but thats just something you do any time the system is open.

You will need a good vacuum pump, one designed for AC service. The little air powered ones won't get it, you'll need an electric pump. They turn up cheap sometimes. Right now mine is out there sucking down the S10's AC system. I paid 20 bucks for it at a flea market, the bottle of new vacuum oil and the proper fitting for R134a service was about another $25. Once its pumped down, you just charge it. Its about 80% the R12 charge, but you may need to tweak it slightly if it comes out too low. Adjusting the pressure switch also can help, about 1/2 turn out on the screw that you'll find in between the blades of the electrical connector. You want it to drop out in the 20-25 psi range. Stock I think it drops out somewhere in the 25-30 range. I'm a fan of manifold gauges, which also turn up cheap sometimes or the Harbor Freight ones aren't totally awful. The fittings at the end on those are garbage and will fail on you eventually. Mine have both been replaced with MasterCool fittings. One of the knobs also broke, it now has a 1950s Magnavox AM tuner knob on there. If you can find a good R12/R22 set for cheap, you can get the fittings to convert it to R134a service and probably have a superior set of gauges for about the same money.

86+ uses quick connect fittings, 85- uses threaded. If you change the hoses to 86-88 hoses, it should allow use of your existing compressor and the newer condensor. New replacement type condensor will likely be the more efficient type, but the originals work OK too. Mine is an original used from an 88 and it works. I have underdrive pullies, so between the reduced compressor action and reduced fan it really kind of sucks in traffic but I don't know that a newer condensor would be a magic pill for that. My evaporator is original. If you don't screw up the inlet tube changing the orifice, it will likely do the job just fine. They can fail and leak if you manhandle the fittings but short of idiotic abuse they aren't usually problematic.

[kishy]

Information! I love information!

So, ester is the oil choice then, for sure? Because it's impossible to completely evacuate the system of all traces of the mineral oil?

"Good" refit fittings vs bad, I'm surprised there would be meaningful differences from one to the next. Is the concern that they leak at the mating point, or that the valve is no good? Or is there even a valve in them at all? If the original valve in the original fitting is still used then I guess that's not a concern.

Quick-connect vs threaded connections does make sense for the difference from 85 to 86. Is one connector type more prone to issues or is it all down to the O-rings? I presume there is a replaceable rubber seal/ring in the threaded connectors, and also presume the quick-connect ones look and work the same as the fuel rail connectors that I'm already familiar with.

As far as the tools go, it sounds like it's a minimum $150-200 investment if going for the cheapest cheap Chinese new stuff (aside from luckily finding something in the used realm), for an electric vacuum pump and manifold gauge set with hoses, fittings, etc. It doesn't sound like it's necessarily worth it financially to go the DIY route here. Might want to anyway, though...

Hoses. There are a number of references online to the idea that hoses used for R12 are not going to hold 134A successfully. There are just as many references to that being nonsense. Thoughts? And as an extension of that, if I have to buy new stock replacement hoses, they are most likely going to be old stock and "designed for R12". Is it exposure to R12 that would cause this issue and the hose is the same otherwise, or is there a different rubber composition to begin with?

Thanks folks

[TecNickal]

All garbage. Hoses are fine. Just the fittings for r134a may not be there.

Cheap parts store conversion fittings are usually the source of leaks. That was the problem with my 89, 90. Junk Chinese rubber

Trick with AC is everything being clean clean clean. Replace every o-ring you can except the compressor seals/gaskets.

Lubricate inside the bore of where a quick connect attaches as well as lubed o rings. PAG oil is also important for this. Chaffed o rings can mean a leak. Put a quality orfice tube in. Accumulator would be nice too...
I've done AC on my own on three cars now - the 89 still is frostbite like. The old Taurus is still freezing. And Zach's 87 is still freezing cold.

[kishy]

Well. Initial parts batch is ordered, mainly because my fan clutch is toast as it is and if I'm creeping up on 210 as it is now, with working A/C it won't get any better. Car does have a very skinny cheap Chinese rad though which I'm sure isn't helping. I'm aware it may have to be upgraded if the additional heat from the condenser overwhelms it.

Apparently the Four Seasons accumulator is discontinued, per my local parts store. RockAuto still has them.

So fan clutch, accumulator, orifice tube, o-ring kit, and valve core kit are on their way. I figured these are the minimum items to replace, and leak-testing may or may not reveal additional parts, which I'll worry about at the time on an as-needed basis.

I'll see about arranging the leak testing in the next couple weeks, which will give me a better idea of exactly where my problems are. I'll also start hunting for the tools to "DIY", if I can track them down I'll give it a shot. If not, paying a shop isn't the end of the world. Almost the end, but not completely.

And yes, I know to keep the accumulator sealed until immediately before installation, and if it arrives unsealed, to get another one.

[sly]

I say use the ester oil if you're not replacing the compressor since there may be some dissolved R12 in there. If you can get the system completely clean (including the compressor), PAG should be fine. Either way... go for the "100" weight if it has the number (most ester oil is 100 anyhow).

My accumulator just arrived unsealed and is already back to UPS for return. f'n amazon and no packing material. If the next one comes without packing, I'm just going to the parts store to have them special order it.

[gadget73]

The better R134a fittings require that you remove the valve core from inside the R12 fitting, and the replacement one screws on and provides it's own valve. The cheapie ones just have a pushrod that use the original R12 valve. They're prone to sticking and leaking. I like the steel fittings too.

Newer hoses are called barrier hoses, but honestly I don't know that they make a big difference in leakage vs R12 ones provided the original hoses are good. Once in a while you'll see them start to leak at the crimps.

Quick connect vs threaded, don't know that it makes a big difference honestly. Both rely on a rubber O ring as the actual seal. Every connection in the system actually seals that way.

Random thought, I want to say the 1986 evaporator is a spring lock, 85 is threaded. I don't know that you'd be able to do the condenser without the evaporator because there is probably no liquid line to interface the spring lock condenser with a threaded evaporator.

[Kodachrome Wolf]

And Zach's 87 is still freezing cold.

I can attest to that! Love running the A/C in the '87; gets cold super quick.

The '97 on the other hand right now, not so much, but hopefully soon.

[kishy]

I say use the ester oil if you're not replacing the compressor since there may be some dissolved R12 in there. If you can get the system completely clean (including the compressor), PAG should be fine. Either way... go for the "100" weight if it has the number (most ester oil is 100 anyhow).

My accumulator just arrived unsealed and is already back to UPS for return. f'n amazon and no packing material. If the next one comes without packing, I'm just going to the parts store to have them special order it.

That's crap. Has an actual human acknowledged the issue and said they're going to address it or are you hoping for the best with the exchange?

I like Amazon but rarely find them to be competitive with my go-tos for car parts: Canadian CarQuest local store, online order for in-store pickup at Advance in Detroit, or RockAuto either to my Canadian or US address. Between those three, the cheapest option in a brand I'm comfortable with can usually be found.

The better R134a fittings require that you remove the valve core from inside the R12 fitting, and the replacement one screws on and provides it's own valve. The cheapie ones just have a pushrod that use the original R12 valve. They're prone to sticking and leaking. I like the steel fittings too.

Newer hoses are called barrier hoses, but honestly I don't know that they make a big difference in leakage vs R12 ones provided the original hoses are good. Once in a while you'll see them start to leak at the crimps.

Quick connect vs threaded, don't know that it makes a big difference honestly. Both rely on a rubber O ring as the actual seal. Every connection in the system actually seals that way.

Random thought, I want to say the 1986 evaporator is a spring lock, 85 is threaded. I don't know that you'd be able to do the condenser without the evaporator because there is probably no liquid line to interface the spring lock condenser with a threaded evaporator.

I went digging through a drawer of junk and found some junkyard-obtained R134A conversion fittings I had pulled a few years back. I have one set with the built in schrader valves, and to boot they're shiney and new looking, as well as another set that uses the pushrod you described. Assuming the little o-rings in the shiny new looking fittings are good I may not even need to buy new ones for that part of it. Any sign of leakage and I'll play it safe with new ones.

Hoses...the cost to replace them is meaningful ($100+ for the two), so I'm going to evaluate the ones I have. If no leaks at the crimps and no obvious defects in the rubber I'll probably just run what I have.

That occurred to me as well re: if I wanted to swap to quick connects. I poked my head in the 91 tonight and you're right. No real sense going to the quick connects unless I need to replace the condenser. If I do have to, then I'll work out the cost of replacing everything, but that also seems to include the compressor, since the quick-connect manifold is for a Denso compressor, not an FS6...so long story short, the chances of that making sense are slim.

On that note, I can't seem to confirm for certain...is the Denso unit on my 91 an FX-15? If so that obviously paints a bleak picture for the idea of rehabbing that A/C system (this thread is for my 84 TC, but down the road, the 91 GM is a target also). It got a new compressor in '97, if that means anything.

[DerekTheGreat]

Well. Initial parts batch is ordered, mainly because my fan clutch is toast as it is and if I'm creeping up on 210 as it is now, with working A/C it won't get any better. Car does have a very skinny cheap Chinese rad though which I'm sure isn't helping. I'm aware it may have to be upgraded if the additional heat from the condenser overwhelms it...

I can second that you will want another radiator. While cruising Wootward 1 or 2 years ago I watched temps climb until finally the computer killed the A/C. It will overload the system if it's sweaty balls hot outside and you're in stop & go traffic with minimal wind.