A/C Help

[Security guy]

My truck's an '86 Silverado with the factory air. It has the old R12 system yet and it don't work. Living in Florida, it's that time of year where it's kinda needed. I think the compressor is shot as there is oil residue on the underside of the hood where the compressor is. I know almost nothing about a/c so asking for some help. I'm wanting to convert it to the new R134a. I am mechanically inclined, so I can replace the compressor if needed and other mechanical stuff, but I don't want to get involved in charging it, etc.. Do I need a new compressor and all new components? Or is it better to take it to a shop and let them change it over for me? Any ideas on cost to change it over and get working? Any help is appreciated.. Thanks!

[77 Big 10]

I have a 77, the AC was not working. I bought a conversion kit at the FLAPS and put it on. Its just a few fittings, one for the high and one for the low side. I then bought a leak detection kit, (glasses, small ultra violet flashlight) and a can of the r134a with the dye in it. I put a small amount in and found that a hose was leaking. I got it on evilbay, installed it and put the r134a in. it was easy. With the hose and gauge, you can see if you need a compressor. I live in the low desert near Palm Springs CA and it gets really hot here, but not in my truck. Hope that helps.

[Security guy]

It's been years since I had to look into this, but don't you have to change the compressor oil to be compatible with the 134a? The last time I researched this was when the new 134a had just come out. At that time, you had to get a new compressor, flush out the whole system, etc... which I don't know how to do. And what is 'FLAPS'?

[Chevy_mud_truck]

Last one I did was almost the same thing but I had to change the compressor it was leaking

[tucsonjwt]

I would take it to more than one "good" shop for an evaluation. R12 compressors all throw oil from the front and it lands on the hood. There are some modifications to help remedy this but nothing will stop it completely. This does not mean that your compressor is "bad" - it may need some work.

R12 is still available and would be a better choice for your truck. Most likely AC shops you contact will have it, and you should be able to get it for a fair price since nobody uses it anymore.

If you convert to R134A you should also install a new cross flow condenser because your R12 condenser would not work very well with R134A. Also, if you convert to R134A you should have a "pusher" fan installed in front of your radiator to compensate for the reduced cooling capacity of R134A. I added a fan from a late 90s GEO (since I have limited space due to a factory oil cooler in front of the radiator) and have it wired through a relay to switch on when the AC compressor is running.

Junkyards will have lots of working fans - just make sure that it is a pusher fan (installed in front of the radiator, not behind the radiator) - see other posts on this site for help on this issue. You can bring the 18V battery out of your drill/driver to check if it is working at the junkyard - use 2 pieces of solid 12 gauge copper house wire stuck into the contacts of the battery and attach alligator clips and stranded wire to the fan leads.

Even if you get your compressor working, expect other issues to pop up. Your heater control has vacuum valves and actuators attached to it, along with the associated vacuum hoses. You can check the LMC catalog to get an idea of all of the parts. New aftermarket HVAC heater controls for the dash are available and are probably a better idea than trying to rebuild the old one.

In short, I would try to keep your system R12. If you must go to 134A, be prepared to spend more $$$ for a new cross flow condenser with relay controlled pusher fan - but these are things you can do by yourself with minimal skill required. You will/should have a professionally shop evacuate and recharge. I would have an A/C check at a professional shop and have them evacuate it if they find issues - then you can install a new condenser and fan if you decide to convert to 134A, Once you get an estimate on repairs you can decide what you want to do.

There is a new R12 aftermarket compressor available which is supposed to be lighter and better than an OEM rebuilt compressor. I have never seen one in use so I don't know if they are any good.

http://www.oldairproducts.com/catalo...120132081.html

[77 Big 10]

Friendly Local Auto Parts Store. 6 years on the conversion and no issues.

[tucsonjwt]

I have had two old style A6 compressors for R12 converted to 134A in old squares and used the original compressor - you do not need to change to a newer style compressor, but the performance of you old compressor will not be as good as with R12 freon. That is why you will need to add a cross flow condenser and pusher fan to compensate for the 134A, or stick with R12. I would try to stick with R12, but only after fixing all leaks in your ac system.

Some posting here will say that you don't need any cross flow condenser or pusher fan - just convert to 134A and be done with it. If you live in a hot and humid place this likely won't be enough. I need a super cool in desert AZ.

[Security guy]

Cool... Thanks for the info guys.. I may talk to some shops around here and get some more info and decide what fits best. I'm not opposed to keeping it r12, just didn't want to spend money on it if it's gotta be changed over soon anyways... as far as the Flaps, I'll have to remember that...(although some are not that 'friendly'.. lol )