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AC QUestions! R-12 retrofit to r134a? 91 Suburban What can I do?

R

RED MONSTER 4X4

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Hey guys!


Being in southern California high desert AC is a MUST! I just replaced the faulty Blower motor but My 91 Suburban has apparently run out of R-12 freon. should I be a jerk and just find R-12 elsewhere?(mexico) or is there a cheaper,easier, legal way to either retro the current system or use a compatible freon? Again, I am brand new to this truck and appreciate all the help this board has to offer! Just checking out my options here, summer is FAST approaching!!

Secondary question, My truck is equipped with the rear AC unit also,Never seen anything like it! Do I need to do anything to that? or will it just run from the front to the back? from the diagrams on LMC it looks to have line from the compressor in front to the rear compressor? Is this true?
 
Alot of the guys on here just get rid of the A/C. But I just got mine working again. I guess I was lucky, it was already retrofitted. I'm pretty sure you just have to put the retrofit fittings on it and get it charged. (You may need to get a new compressor)
The problem you might find is finding a place that will actually charge it though. The shop that I work in has a policy that we do not work on anything that is R-12 or anything that has been retrofitted. We don't want to contaminate the R-134A charging system we have with R-12, but I did mine anyway. The dealership I used to work in would do it though. Our machine had a seperate tank we could switch to when we would evacuate the system if it had R-12 or was retrofitted and we were't sure what was in it.
There is more than likely a leak in your system though. And to put the retrofit kit in the system needs to be evacuated first. Then put in the fittings, might as well replace all the o-rings, and the orifice. Then bring it back to the shop, they'll evacuate it again, put a vacuum on the system, then depending on the machine they can test the system for leaks (it won't test the schrader valve though...), charge the system, and more than likey put some die in it to make sure if it is leaking they can find it later on, or you can have the shop replace the o-rings and orifice while they are doing the work...

I can't help you with the rear system though.
 
The rear ac unit uses an expansion valve, front uses a orifice tube, the whole system runs on one compressor, the line is just split to run compressed freon back to the ear at the same time as the front.

Personally, if you're going to do the retrofit stuff, I'd change out the condensor to match the newer freon, it'll work much better. I did a retrofit on mine shortly after I got it, it worked fine driving down the freeway, but in city traffic, it wasn't much of anything but a swamp cooler, didn't cool very well. It needed the condensor designed to run r-134 to get the freon cooled back down.
 
Good points above, but we have just sucked out the R12, change fittings and add oil to the old R12 system, now retrofitting it now to R134A.

As far as changing the compressor, or condenser, or Accumulator, I've done it all different ways but always seem to make it work.

For the hell of it, I've changed fittings and refrigerent only and its worked out. Yes, not as efficient in stop and go traffic, but still works without a lot of extra hassle.

Remember only fill the 134a to 80-85% of the R12 capacity and should be fine. Watching the pressures will dictate total capacity.
 
I just remembered, the reason I mentioned changing out the condensor is probably something I would really do in the hot climate like we have here in Phoenix or Vegas areas, in a more mild climate i'm sure it works out ok, but in this heat, the AC just doesn't even get cold at all in city traffic when it's 110-120 degrees outside.

And when i mean it doesn't get cold, I mean like it's suppose to, if I remember, I think it was in the mid 70's at times during stop & go traffic situations, but there's also a very humid feeling to the air when it does this, so it really doesn't feel all that great.
 
Oh, I know the AZ traffic all to well with a mediocre AC system. The quick retrofit works good here because out ambient temps rarely get to 100
 
I did my 86 burb when I got it, works fine...the only thing I would do different is use a sanden and a parallel flow condensor.


here's some good info for ya...

http://coloradok5.com/forums/showthread.php?t=193200


the front & rear are integrated... drawing a vacuum & filling does the entire system.
 
Thanks guys! fantastic info! very Helpfull!

Have any of you herd of EZChill? it is a kit for roughly 60$http://www.walmart.com/ip/EZ-Chill-AC-Recharge-and-Retrofit-Kit/16888792
http://www.youtube.com/watch?v=5Q0sMQJre60

Seems legit, he is even using a CK in the video but this is my first venture in to this, and I am not sure how I would drain it. like the video said, I can get a place to do it for probably free. As we all are, i am on a budget, so cheaper the better, doing some research the reviews are good. So anyone have experience with this product or have an alternate product ?
 
Did you jumper it with 12 Volts? It won't engage the clutch if it is too low on freon. Just try a jumper wire across the low pressure switch.

Martin
 
No clutch action could just mean it's too low on freon, you need to remove the pressure switch on the accumulator and jump the wires in the plug to see if it activates.
 
4xcrazy said:
No clutch action could just mean it's too low on freon, you need to remove the pressure switch on the accumulator and jump the wires in the plug to see if it activates.
Click to expand...


OK, I need to do this as mine is not working either. Exactly where do I jump wires at?
 
Ahh, good idea. will do that! this board is awesome! some really helpful folks here! I appreciate all the help guys! if anyone ever needs computer help feel free to PM me !
 
Unplug that pressure switch on the side of the accumulator canister, take a wire and jump the two connections in that connector plug while the ac is is turned on, the compressor should engage.

Just don't let it run for a real long time unless you're inserting freon, but by then it should automatically kick on once the freon pressure reaches where it needs to be to start cycling the system.

it's how I tested the switch and determined it was bad on my mothers '94 Silverado, jumped the switch, ac got cold, so the switch just wasn't getting the right pressure reading. Replaced the switch, all worked fine so far.
 
I re-did all mine with new AC Delco stuff and it cost me about $850 total.

http://coloradok5.com/forums/showthread.php?t=281478

A/C in California is important and may be worth the extra cash to get it up and running again completely. Still like your truck though...... :)

Unfortunately, you have the added expense of the rear lines too. If you put in a new compressor and there are any small metal shavings in the system, you are going to burn out that new compressor. So be careful how much you throw at this using some of the existing pieces in the system.
 
Your 134a conversion will create too much head preasure and is the reason it dosent cool when sitting. The systen will not take as much freon to cool in comparison to the R12. I placed a electric fan in front of the condenser and taped up the ducting behind the dash. also block in the heater core hoses with valves to keep from heating the plentum.:waytogo:
 
If your compressor still works and didn't explode basically, you should be fine, you obviously have a leak somewhere though you should tend to first.

I just worked on a friends van, he was complaining that the ac was not as cold as it was when he got the van a few months back, he brought it over, I searched alittle and found the schrader valve was leaking, there was already hardly any pressure in the system by the time he brought it over, so I removed the ld one, replaced with a new one, refilled the system and it was cold again.

Haven't heard back from him yet, been several weeks now.

Usually you'll be able to tell where it's leaking from just by the oil accumulation around the area of the leak. But normally it's either just seals at connections or that schrader valve, either high or low pressure side.

look over the lines, see if there is any oil around any fittings, get a manifold gauge set on it to see what kind of pressure is still in the system.

Funny thing about the r-12, they don't want people messing with it, venting it into the air, but 9 times out of 10, the reason people are messing with the ac system, is because it has already leaked out into the air by itself.. eh, whatever, I still think it has to do with DuPont losing the patent on the product, they don't want to lose business, so they made a new freon, paid political people to outlaw the r-12, now you can't buy it here, funny how it's still sold in other conutries though.
 
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