R12 A/C top off - need help fast

[kok328]

First let me apologize for the urgency of this request. Read on and you'll understand.

1992 LeSabre. Compressor was short cycling and not providing cool.

I tapped my last can of R-12 and the system would not take it.
I tried the hot water trick, held the can upside down, etc.....
I check my schrader valves at the connections and R-12 will leave the can if the system will only suck it up.
I managed to get my compressor engage time from 5 to 8 seconds after about 30-45 min. of charging before I called it quits. From the feel of the can, it is still full. It never frosted or even became cool. My hi side line was a little sweaty and my low side line was cool and dry.
I'm hoping this will tell somebody, something, hopefully it's normal. The temp coming out the dash vents is 70 degrees F.

This can is already tapped and doesn't hold forever (24-48hrs.).

I hoping that someone can tell me why the can does not dispense or how to test the pressure switch controlling the compressor before this can looses pressure (liquid gold).

[polarzak]

Originally Posted by kok328

First let me apologize for the urgency of this request. Read on and you'll understand.

1992 LeSabre. Compressor was short cycling and not providing cool.

I tapped my last can of R-12 and the system would not take it.
I tried the hot water trick, held the can upside down, etc.....
I check my schrader valves at the connections and R-12 will leave the can if the system will only suck it up.
I managed to get my compressor engage time from 5 to 8 seconds after about 30-45 min. of charging before I called it quits. From the feel of the can, it is still full. It never frosted or even became cool. My hi side line was a little sweaty and my low side line was cool and dry.
I'm hoping this will tell somebody, something, hopefully it's normal. The temp coming out the dash vents is 70 degrees F.

This can is already tapped and doesn't hold forever (24-48hrs.).

I hoping that someone can tell me why the can does not dispense or how to test the pressure switch controlling the compressor before this can looses pressure (liquid gold).

Sorry I really can't help, BUT, if you do loose all of your R12, you can buy something called Glacier Gold. It mixes with R12 and worked well for me.
For reading info and a dealer, check glaciergoldrefrigerants.com
Hope someone can help you. Good luck

[maxwedge]

Originally Posted by kok328

First let me apologize for the urgency of this request. Read on and you'll understand.

1992 LeSabre. Compressor was short cycling and not providing cool.

I tapped my last can of R-12 and the system would not take it.
I tried the hot water trick, held the can upside down, etc.....
I check my schrader valves at the connections and R-12 will leave the can if the system will only suck it up.
I managed to get my compressor engage time from 5 to 8 seconds after about 30-45 min. of charging before I called it quits. From the feel of the can, it is still full. It never frosted or even became cool. My hi side line was a little sweaty and my low side line was cool and dry.
I'm hoping this will tell somebody, something, hopefully it's normal. The temp coming out the dash vents is 70 degrees F.

This can is already tapped and doesn't hold forever (24-48hrs.).

I hoping that someone can tell me why the can does not dispense or how to test the pressure switch controlling the compressor before this can looses pressure (liquid gold).

I am sure you know this is not the proper way to work on any ac system, low and high side pressures must be taken to determine the rerason for not cooling. Blockage in the system, weak compressor, plugged orifice, defective press. switch, are all possibilities here.

[kok328]

Assuming my can of freon doesn't leak down by the time I get to my guages, what readings should I be seeing on the hi-side, low-side and differential w/ & w/o compressor engaged?

Better yet, is it legal for a shop to recover my R-12, make repairs and then put My R-12 back into my system. I really think that my R-12 level is not low and I should a have sufficient quantity in the system to restore it to OEM.

[maxwedge]

Originally Posted by kok328

Assuming my can of freon doesn't leak down by the time I get to my guages, what readings should I be seeing on the hi-side, low-side and differential w/ & w/o compressor engaged?

Better yet, is it legal for a shop to recover my R-12, make repairs and then put My R-12 back into my system. I really think that my R-12 level is not low and I should a have sufficient quantity in the system to restore it to OEM.

28-33 low side running compressor maybe 170-200 high side. If the shop has a cfc license they can do r12 work, with the proper recovery equipment of course,.

[kok328]

I really want to fix this without the help of a shop. However, it sounds like to get a proper diagnosis, I'll have to pay out the A and possibly lose my charge.

I drove this car for 2 years w/o A/C thinking that it would require a conversion ($600 - $800). In the final year, I got so tired of sweating my brains out, I poked around enough to find that I needed a $12 relay to get the system working again. I'm thinking I'm not going to be so lucky this time. It cost about $80 just for a diagnosis and of course it comes with the usual "it could be this, that or the other thing; without spending more money, I can't tell you what else may be wrong", disclaimer.

Obviously the pressure switches were installed on the system to prevent damage but, how are they tested?

Is it possible to change these switches (low/high) without losing my charge?

I made a few calls around town and they are telling me they can't use R-12 to charge my system, doesn't matter who's R-12 it is or where it came from. They say they can only dispense R-134A and this will require a conversion but, only after they go through the system on an hourly basis.

[maxwedge]

Originally Posted by kok328

I really want to fix this without the help of a shop. However, it sounds like to get a proper diagnosis, I'll have to pay out the A and possibly lose my charge.

I drove this car for 2 years w/o A/C thinking that it would require a conversion ($600 - $800). In the final year, I got so tired of sweating my brains out, I poked around enough to find that I needed a $12 relay to get the system working again. I'm thinking I'm not going to be so lucky this time. It cost about $80 just for a diagnosis and of course it comes with the usual "it could be this, that or the other thing; without spending more money, I can't tell you what else may be wrong", disclaimer.

Obviously the pressure switches were installed on the system to prevent damage but, how are they tested?

Is it possible to change these switches (low/high) without losing my charge?

I made a few calls around town and they are telling me they can't use R-12 to charge my system, doesn't matter who's R-12 it is or where it came from. They say they can only dispense R-134A and this will require a conversion but, only after they go through the system on an hourly basis.

Without a cfc license they cannot service r12, many places do have a certification but tend to lean towards a conversion, which on an old system can be iffy. These pressure switches can be jumped if done in the right sequence.

[kok328]

Well, all I can tell you is that it won't take a charge.

If I jump out the high pressure switch, it still short cycles (both normally open and normally closed).

If I jump out the low pressure switch, the compressor remains engaged but, I chickened out on seeing how long it would stay engaged, not knowing what really causes the compressor clutch to cycle and not realizing at the time that I was jumping the low switch and not the high switch (learning as I go). I'm currently under the impression that these switches are a fail safe and not a control circuit. If I can get information on what causes the clutch to cycle, I might try leaving the low switch jumped out to see if it will cool and cycle normally.

However, l'm thinking that a blockage in freon flow to the low side should cause high pressure on the high side (the stuff has to go somewhere). I guess the low side trips out before the high?

[HotZ28]

It is that time of year again and every other thread has a question concerning an AC problem! I know how you all feel, been there and done that! As usual, maxwedge is right on target with the above post.

It sounds like you have a restriction in the orifice tube, which is normally caused by the early stages of compressor failure. Usually, when the compressor begins to fail, it is due to the lack of oil circulation, or simply, the lack of oil.

The older compressors such as yours (HR-6), uses the low side pressure switch to cycle the compressor off/on. On an R-12 system, the switch will make at around 40 psig to turn the compressor on, (clutch engage) and open at 19-22 psig to disengage the clutch.

If the system is operating normally, the low side hose, will be very cold (32-38 deg) and the high side will be very hot to the touch. You would not be able to hold your finger on it for more than a second. Use caution “jumping” the low side switch and only do that long enough to check pressures or to see if the accumulator (or low side line) will get cold. If you do have a restriction in the orifice, the system cannot circulate the refrigerant and oil as needed. In addition, if you run it too long with the switch “jumped”, you risk damaging other parts of the system. Your situation is not unique; in fact, it is quite common for a 15 yr old system. Parts and lubricant just seems to wear out!

If you want to see some more info on the same subject, check out the recent AC threads in the PA forums. You will find some similar problems and some more advice on how to approach the problem.

One final note, you can change the low side switch without loosing the refrigerant. Behind the switch, there is a Schrader valve, that will prevent a leak. You could remove & replace the switch; however, I doubt it would have any positive affect on your problem.

[kok328]

Thanks guys, your telling me exactly what I don't want to hear but, unfortunately for me, your both correct.

I do have a 14oz. can of R-12 Oil Charge but, it sounds like the damage is already done.

I was looking at parts prices for the hi & low pressure switches and Autozone indicates the opposite of what I've been assuming all this time or they are wrong (surprise).
I believe the low pressure switch to be mounted off the accumulator (on the large tube) and the hi pressure switch mounted inline at the compressor (on the narrow tube).
I jumped out a switch at the accumulator and the smaller line was sweaty and the larger line was room temp. Does this confirm a clogged system?
Can either of you clarify this for me?

I simply refuse to put hundreds of dollars into the A/C system so I guess that leaves me with three choices:

1. - replace the low pressure switch and see if that fixes the problem (most likely if the pressure guages tell me that I'm within spec).

2. - jump out the low pressure switch, benefit from the cool and let the system self destruct (not like it's going to do me any good like it is anyhow).

3. - walk away from this one and continue to sweat my A off.

P.S.- Just went throught he PA forum for the last 2 months and found nothing on A/C.

[HotZ28]

Originally Posted by kok328

I believe the low pressure switch to be mounted off the accumulator (on the large tube) and the hi pressure switch mounted inline at the compressor (on the narrow tube).
I jumped out a switch at the accumulator and the smaller line was sweaty and the larger line was room temp. Does this confirm a clogged system?
Can either of you clarify this for me?

I simply refuse to put hundreds of dollars into the A/C system so I guess that leaves me with three choices:

1. - replace the low pressure switch and see if that fixes the problem (most likely if the pressure guages tell me that I'm within spec).

2. - jump out the low pressure switch, benefit from the cool and let the system self destruct (not like it's going to do me any good like it is anyhow).

3. - walk away from this one and continue to sweat my A off.

P.S.- Just went throught he PA forum for the last 2 months and found nothing on A/C.

A couple links from the PA forums FYI:
http://www.automotiveforums.com/vbul...d.php?t=425186
http://www.automotiveforums.com/vbul...d.php?t=587204

You are right about the location of the high & low switches. Next, jump the low side switch, then take the car for a normal drive (no high rpm) while using a thermometer to measure the temperature of the air coming out of the vents & report back.

[kok328]

I put some HVAC guages on the low side. When I first engaged the comressor, the pressure dropped to zero. When I let go and re-engaged the compressor a few seconds later and every try in between rests, it dropped and held at 11psi. I don't have the proper fitting to see what the high side is doing. The low pressure side rises to 75psi when the compressor is disengaged.

I ran the car about a mile down the road @ 40 mph in VENT mode to clear the vents and get a stable reading on the T-Stat in my vents; 80 degrees. I turned the car around drove a little til I got up to 40 mph and hit the A/C. It dropped the T-Stat to 60 degrees before I let go of the compressor. Got back home and reconnected the low side pressure switch and ran the A/C; it still short cycled.

Everything but, the front passenger door handle illumination (bulb) is working on this vehicle but, no A/C.
Makes it so I don't even want to drive it anymore.
Darn cab-fwd design is just a big heat asborbing pad after a day in the sun.

[HotZ28]

The low side should read between 80-100 psig with the compressor off. With the compressor on, you should be somewhere between 30-40 psig, and no more than 50! Any higher than that would indicate a restriction in flow, or low on "Freon." Go ahead, run it longer with the switch jumped, and see how low it will go on vent temperature. It will not hurt anything at this point!

[kok328]

I'll see what happens and let ya know.

Your saying that high pressure on the low side = restriction or low freon.

I seeing low pressure on the low side thus, the low pressure switch cuts the system off (logical?).

I was thinking of just running short cycle to attempt to clear a clog.

Am I about to get lucky with replacing the low pressure switch.

Sorry to get ahead of the situation but, it's hitting the 90's this week.

p.s.- sorry for the private message, you posted just as I sent it (scary).

THANKS FOR HANGING IN THERE WITH ME!

[MT-2500]

Originally Posted by kok328

I'll see what happens and let ya know.

Your saying that high pressure on the low side = restriction or low freon.

I seeing low pressure on the low side thus, the low pressure switch cuts the system off (logical?).

I was thinking of just running short cycle to attempt to clear a clog.

Am I about to get lucky with replacing the low pressure switch.

Sorry to get ahead of the situation but, it's hitting the 90's this week.

p.s.- sorry for the private message, you posted just as I sent it (scary).

THANKS FOR HANGING IN THERE WITH ME!

As said you need to be certified to add R-12
Also to safe and proper check a system you need a low and high side gauge like one of these.
http://www.ackits.com/merchant2/merc...uct_Code=66773

Next you need to jump the compressor and check low sde and high side pressure at idle and at 2000 rpm.

If low side is under 25-30 lbs and high side is low 150 lbs
You need freon.

If the system will not take freon with compressor running and low side 0 to 25 lbs and high side under 150-250 lbs.
Check the fittings on the can tap and the lowside.
If the low side gauge is working it should have a good conection and freon should go in.

After low side gets to 30 lbs and high side 250 or over do not add any more freon.
Good luck MT