Hey Gents,

Happy New Year to you all at FTE.

Now, Last year sometime during the summer, I added a can of R134, the pressure was just below the line for the pressure according to the kit I bought at Wal-Mart.

Now, when I run the A/C or Defroster or Mix, I can hear the compressor come on (or off for that matter) and it makes the engine stall, I thought it was a clunk in the tranny or rear end and have isolated it to the A/C pump.

The A/C works well (run it bout once a month for giggles) and the defroster works great.

Should I have the old freon taken out and replace with new and would a mechanic do that only without probing around and saying that I need a new compressor, clutch and run my bill up? Or, can I do it myself with a kit that is unknown to me?

There is no squeeking or grinding or nothing, the noise is louder than normal to me.

It's a 95 3.0 shorty with auto and no rear air with 174,000+ miles.

The van runs great and don't want to replace the A/C with little or no funds.

Thanks for your humble opinions.

Aaron
Nappers

 

If the a/c was cold before you added refrigerant, you might have an overcharge. This happened to me once. In my case , the compressor stopped and the belt screamed (Like a cat, etc). I let some refrigerant out and the system ran fine again. This happened with less than 1 can added. I thought the system was 5 years old and surely 1 can was needed. Pressures are not a good indicator of system charge. Best simple indicator of low charge is rapid short-cycling of clutch on a warm day with little cooling. If clutch does not cycle on the LP switch but some cooling exists, this means overcharge. over or undercharge=low performance.

Accumulator should be cold and clutch cycling, this means evaporator is full of refrigerant which is desired situation. Life was simpler when they had sight glasses in the lines. Obviously much too expensive to use now.

Ken

 

It could be an overcharge. If this was a freon vehicle, then the old freon should have been removed, the evaporator flushed, the condesor flushed, the accumulator replaced. It is against the law to mix refrigerants, and mixing R-134a and Freon results in toxic acids in the system. You will have to have the entire system flushed, and any damaged components replaced. IF your system was R-134a to begin with, no harm done. The kits you buy are nearly worthless. To charge an AC system properly, you need to monitor the high pressure side, no the low pressure side. The guages that come with the kits monitor the low pressure side only, and the readings are inaccurate, because the incomeing coolant from the can alters the readings. You also need a highly accurate thermometer. To do it properly you need minimum:
1 Manifold Guage Set
1 Thermeter, but 2 is better
if you are converting to R-134a from R-12 you need
all new seals, they should be replaced any time the system is opened.
an new accumulator, the original accumulator is not compatible with R-134a
in some cases a new pressure cycleing switch (on an Aerostar, the switch is usually adjustable, but should not be adjusted without the use a a manifold guage kit.)
replace any damaged hoses. So long as they are undamaged, the old hoses do work with R-134a
A flush cylinder, and at least 2 quarts of flushing solevent. This is to remove the old oil and any contaminants from the system. Do not flush the compressor itself. Flush the Evaporator, Condensor, and any hoses you plan to reuse.
a new orfice tube. The old one is likely plugged, and they are cheap. You will also need the tool used to remove the Orfice tube.

Overall, you are looking in major money.

Now, yes, you could proably do a job that worked for much less, but realize, the less thorough you are in retrofitting, the more likely you are to have problems down the road, the more expensive they are likely to be, and your time, money and effort will have been wasted, and you may have to waste more time, effort and money. Before you quastion may statements, note that I am certified to handle refrigerant, and service all mobile AC systems. You the consumer cannot buy R-12, but I am authorized to buy any legal refrigerant. I have thuroughly researched every refrigerant out there, and to be quite honest, R-134a is not a very good refrigerant to retrofitting, but it does have the benefit of being fairly cheap and available to the general public. I have personally tested a number of different refrigerants out there, and am knowledgable about all of them. By persoanl favorite is Freezone, because it works better than the original R-12, carries both R-12 and R-134a oils, does not react with anything, operates at a lower pressure, has its own lubricant right in the can, and has the best warranty in the industry. (Useing it voids the manufacturers warranty on the compressor, but they carry their own warranty that is better than the manufacturers. ) Freeze-12 is decent, but does not contain its own lubricant, and so PAG oil must be added manually. Any refrigerant that contains R-22 is not suitable for easy retrofit into automotive AC systems. It requires all new seals and hoses, and often new compressors too. It is more prone to leaking, and according to the EPA, it is almost as bad for the ozone as R-12.

 

Dear Khanty,

Are any of these refrigerants compatible (mixable) with r-12. Remember "refrigeration" happens on the low side. high side pressures don't tell you much, mainly how well you are condensing.

Ken

 

Hi Khan:

Nappers has a '95, so his system should be based on R134a.

Hi Ken:

I think the pressure on the high side not only tells you how much you are condensing, but also what you are compressing. Too high of a pressure means that you might be trying to compress liquid refrigerant, and that would be really bad news, causing the compressor to seize up just as you describe above. Overcharging the system is thus a really bad idea.

 

Copper,

You are right, all pressures are important but many times when I service any a/c including home or fridgigator in kitchen, I only hook up low side. Some systems only have a low side tap but all pressures tell you something. It sure was interesting when that compressor stopped with only a 1/2 can overcharge. that was a '90 Legend. It didn't stall the engine though. Made a lot of noise, I thought I just spent a half grand.

ken

 

Hello Ken,
This is straying from the original poster's question and I do apologize, but I was wondering about that half can of coolant you added. If it were dumped in quickly (as in having the can upside down) you may have flooded the accumulator and sent liquid into the compressor rather than a gas. That would certainly stop the compressor cold but once the system equilibrated it would have worked again. In which case, it would not have been the volume added but the manner of addition. I have "inadvertently" overcharged my A/C system but rather than causing the compressor to stop, the relief valve just lets go. Just a thought.

 

khantyranitar, 93 was the last year for domestic R-12 cars. His was a 95 so I seriously doubt that it was converted back to R-12.

Nappers, what made you think to purchase the wal-mart kit to check the pressure? Were you not getting enough cold air? Or some other reason?

I am wondering if it is some other issue causing this that was there to begin with that was magnified with the addition of freon.

 

Every can of R134 that I have sitting out in my garage has on the label to charge with the can upside down.....

 

That's strange, I just went out to check and every can I have says to use with the can in "upright" position. What are we to make of this? I seem to recall when I was messing around converting my A/C system several years ago that you ran a greater risk of locking up the compressor if you flooded the accumulator by running in liquid coolant rather than letting just the gas enter the system during recharging. Anyone else have an opinion on this stalemate?

 

Ok, I went out to my garage and brought in two different cans of R-134a.


According to the instructions on the Johnsen's R-134a (1,1,1,2 tetraflouretano)

"Hold can upright to charge gas, use only the required amount"

Now on my can of Interdynamics R-134a High Millage (1,1,1,2 tetraflouroethane, 2 oz of Polyol Ester oil)

"Shake can well. Prepare can for charging using an Interdynamics dispensing valve and hose. Connect only to low side service port."

Sense it did not say on the can, I re-watched the video CD that came with the kit and it also says to keep the can in an upright position.

Cookkid, are you aboslutely sure it says that? If it does, what brand is it?

 

Charge it in upright position, submerged in a warm bath of water, and rev the engine to about 2000 rpm. It takes one heck of a long time to charge it this way compared to the upside down position, but it's safer for the compressor.

 

The van as far as I knew or fiance knew was never serviced and it wasn't quite as cold as it was (a country song?) so, I bought one of those kits with freon (r-134 sorry) with gauges and the what not. The pressure indicated on the instructions to be low on freon, so....I put a can of the stuff in the system and followed the directions on how to do it (can't remember how now) and it got colder and didn't seem to be anything wrong. The pressure did approach the red on the gauge supplied with the kit. I figured now, I may have slightly overcharged it. Thankfully I have a little woman that turns off the A/C on hills, around town and shuts off when parks thus, less where and tear on it.

The noise I noticed is louder than in recent months, the hard engaging (or disengaging, not sure) and like I said, defroster works great and usually run on mix during winter as with 5 hot headed kids breathing in the back fogs her up pretty fast, worse with a load of boys for a 13th birthday. There are no squeels and the belt is fine, just kinda like a clunk every so often when the pump kicks on. Not sure how the system works on defroster, my Yukon doesn't appear to kick on when on defroster, at least don't notice it.

Just trying to figure out if I should bring her in and have it serviced with new freon, clutch and compressor seem to be fine as far as I can tell.

Thanks again you guys.

Aaron

 

Don't know the brand...I used two cans on Wednesday to charge up my daughters cougar....I am sure I read "upside down"....the only thing I have on my shelf now is "Envirosafe" R134 replacement and it also has arrows on the can to show charging is to be done upside down......

 

Before doing anything Nappers, I would re-check your pressure on the low side. Let the a/c max run for about 3 minutes and take another measurement and post it here.


We will go from there.