your system should have the type switch that has a rubber seal in it and you might not lose your Freon, and if you do need to replace any see if you can locate freeze 12 you can get it over the counter and it is better than the 134. JNT

 

he already has it converted to 134.

can't use freon anymore.

 

I added R134 to my A/C system. The compressor started going off and on like it is suppose to do.

I have a pressure gauge hooked up to the low side and it's at 35-45 lbs. BUT, I still have warm air coming out the vents inside. What's up now??? When the engine is off the pressure is at 100lbs. HELP again...thanks Greg

 

same advice as before: take it to a pro for repair.

 

Greg, you really need to be able to see the high side pressure on the system too. Just the low side pressure doesn't tell you much at all, and that cheap low side gauge on the refrigerant can is very inaccurate. See if any of your local parts stores can rent you a manifold gauge set and vacuum pump for R-134a systems. If not there, check local tool rental places, there is a nominal charge per day.
If you can't rent, borrow, or steal a gauge set and vacuum pump then you will need to take it to a shop as quicklook2 recommends. You cannot fix your AC system without those 2 tools. If you can acquire them, I can guide you through repairing your AC. You will also need a set of "Spring Lock Coupler Tools", but those are fairly cheap.

Auto Zone stores in my area rent a manifold gauge set and vacuum pump for a ~$200 deposit. They refund the whole amount when you return them. (The same folks that sell all of that "AC magic in a can'" and other scary Interdynamics junk that doesn't work, so prominently displayed near the counter. Go figure.).

You also need to find the leak before you go any farther. Just adding refrigerant may make it work for a little while, but your new refrigerant will go out through the same leak as the old stuff, and leaks in anything will always get worse right? Recharging will just be throwing money away and possibly damaging your system.

But, for right now there are some checks to do to help figure out where you stand (aside from an obvious refrigerant leak):

Your 89 should have a cable operated blend (temp) door under the dash. Make sure it is closing all the way. Air flowing over the heater core can reduce the AC performance.

Post back with answers to a few questions. :

What was the static (system not running)pressure before you added the refrigerant? How much refrigerant did you add? This is important to know. If the system was near empty, it is now full of air/refrigerant mixed. Air doesn't condense so the system won't cool well, if at all.
It takes ~45psi for the compressor to engage, then it cuts back out at ~32psi on the low side..

What was the ambient temp when you were working on it? With a cool engine, the static pressure should be roughly the same as ambient temperature. If it was ~80+ degrees outside and under the hood was near 120 degrees, that 100psi static pressure is pretty close.
How often does it cycle, on time and off time? Knowing the ambient temp and cycling rate can help to determine what is wrong.
What do the lines right at the evaporator housing feel like? With the AC on and the engine at about 1500 rpm, feel both AC lines coming out of the evaporator case (firewall). When the system is working correctly, they should both be cold and be about the same temperature using your precisely calibrated hand. The suction line (big line) should be cool going back to the compressor. Knowing what the lines feel like can also help in troubleshooting.

Tom.

 

Sure you can! R-12(Freon) is perfectly legal to use in the US. (It's illegal to use it in Canada), you just need a "certification" to buy or handle it. The certification test is now an online "open book" test and costs $25. R-12 can't be "MANUFACTURED" in the US at all and importing it is illegal. Remaining inventory is legal to own, store, buy, sell, use, etc. as long as you don't discharge it into the environment and have proper certification to handle it.

R-12 was outrageously expensive a few years back and not really viable for repairing AC systems. The price has fallen drastically in recent years due to decreased demand. The very newest cars with R12 systems are now 15+ years old (1993) and many of those remaining have been converted to R134a or just aren't worth fixing the AC. The only "real" market is for collector cars\trucks as the remaining pre-93 "daily driver" vehicles are taken out of normal service (scrapped).
There are still many tons of NOS R12 available from the manufacturers, but it is still pricy. In a few years it will be sold on the surplus market for whatever it can bring. Lots of people hoarded 12-16oz cans and #15-30-45-60 jugs of R12 before it was phased out hoping to "cash in" later, but the price peaked about 2004 then sloped down sharply. It's dropped like a rock since 2006.. Many of the "hoarders" missed the peak, and R12 can be bought for as little as $9-12 per pound for a #30 jug of virgin refrigerant today. That's darn close to the retail price for an actual pound of R134A at Advancemurraypepautokragenzone. (Those are all 12oz cans, $7.79 when I looked today).

 

one more time, he converted it to r134 so now he can't use freon (r12) anymore.

 

Sure he can. There's n o "un" conversion needed. Switching back is almost as simple as recovering the R134a and charging with R12.
Basically, the only difference is the oil. PAG oil used in OEM R134a systems doesn't play well with residual R12 and mineral oil in an R12 system. R134 wouldn't carry the old mineral oil used in R-12 systems. Ester oil was developed to work around these issues in converted R12 systems and is compatible with R-12 and R134..

 

I can't remember the exact pressure, but it was in the green (on the gauge)and I am guessing it had 15 lbs in the system before I started. I have added about 2 cans to the system so far.

It was 90 degrees outside yesterday when I was working on it.

The pump is staying on for quite a while now, and is has a steady pressure of about 40lbs.

the lines feel cool, not cold, I got cool air to come out the vents, just not cold like they should be.

 

If there was only 15 psi to start with, there is air in the system for sure. You're also still undercharged, the recommended charge is about 32-26 oz IIRC. The problem is, with air in the system the high side pressure will go way up and can damage the compressor if you keep adding refrigerant. You really need to stop now, get a gauge set and vacuum pump and repair it properly.

 

OK, So after I get the gauge kit, what should the pressures be on the High side and low side when they are hooked up? Should I vacuum all the r134 and air out of the system and start fresh? Thanks for your help, I am learning alot doing this.

 

I bought a gauge set and vacuum pump yesterday. I am ready for some advice. thanks Greg

 

You bought a vacuum pump and gauge set?? Me and my inner tool junkie applaud you!!
That investment won't save you much on this particular repair, but will pay off totally on the "next" one you do (yours, wife, girlfriend, both?, neighbor, etc). Since you spent the $$$, you must have figured that out already.

You need to have the remaining refrigerant charge removed from your system, preferably by a shop with a recovery/recycle machine. If you hook up your gauge set and the hoses aren't tight on the manifold, and the refrigerant leaks out, shame on you!

Now for a visual inspection.
Oil drips, oily dirt, or dried oil marks are good indicators of leaks on AC components. There is oil in the system that leaks out with the refrigerant. Watch for oil slinging from other things under the hood. Power steering pump leaks below the compressor can really send you off on a wild goose chase.

Dry dirt/ dust accumulation is normal under the hood over the years. Oily, caked dirt on AC parts usually indicates a leak. Follow the lines from the compressor, to the condenser, to the evaporator inlet, back to the compressor. Look at the entire face of the condenser (in front of the radiator). Crud caked into the fins in one area is a dead giveaway of a leak.

Compressor- Look for oily dirt accumulation around any hose connections, the front face of the compressor clutch, behind the pulley, and on the lower body of the compressor. Oil, greasy\oily dirt, oil staining indicates leaks. A "belly leaker" compressor usually has visible "water stains" on the bottom.

Hose connections- Most connections are of the Spring Lock type. If you see oily dirt accumulation on any SL fitting, it is leaking. Same for threaded connections.

If you see oily dirt on a crimped hose connection, it is leaking. I've seen this most on the fat "suction" line back to the compressor on 87-93 Ford Trucks. (the accumulator and that hose are an assembly, so it's a non issue. It's replaced with the accumulator).

Post back after a thorough visual inspection and let me know what you find. I suspect you will find one or two Spring Lock connections with crud on them. The compressor shaft seal is always suspect, but I have the same compressor on my 84 Lincoln Mark VII with 218K. No leak there.

 

I found one spring compression connection with the oily looking dirt around it. All the other connections look good, including the pump itself.

 

[QUOTE=graven57;6183847]I found one spring compression connection with the oily looking dirt around it. All the other connections look good, including the pump itself.