No A/C - I’m Lost...


rangerenthiusiast

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Sooooo... I bought a ’92 Ranger Custom (4.0/A4LD/4x4) over the winter. The PO claimed that the A/C worked great (as with everything else he said, a total lie). We’ve had some unseasonably warm weather lately, after a winter that seemed to last forever, so I tried it out.

No cold air whatsoever was forthcoming. I already know that there are leaks in the A/C system, due to this sight welcoming me under the hood:

https://drive.google.com/file/d/18-AkRGC12Py6TODiqfivkW1lg5EEZZu3/view?usp=sharing

https://drive.google.com/file/d/1mXf_BiG6cRs1Z3v-ZxaBbOn70lxfnrBq/view?usp=sharing

Each of the spots I’m pointing to in the pics have green fluid leaking from them.

Additionally, I turned on the A/C in the truck and got out to see what the A/C pump was actually doing. As it happens, the pump cycles on for just about exactly 1 second, then turns off for 5 seconds, and starts the process all over again. It’s very precise in the timing. So my questions are as follows, if anyone can help out:

1. What is up with the cycling on and off of the A/C compressor? Is it detecting that there are leaks due to pressure loss and switching itself off in order to keep from burning up or something?

2. Is it possible to replace the o-rings that are causing the leaks in the system, then recharge the A/C? What’s involved?
I’ve always done all my own mechanic work, but A/C is a bit of a mystery to me (most of my vehicles never had it).

Any help is VERY much appreciated!!!! :icon_thumby:


PS - If anyone can enlighten me on how to embed photos within the text of a thread (rather than hyperlinks, as I’ve done here), it would REALLY help me out!!!
 
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Denisefwd93

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When refrigerant leaks, it. can leave oil residue, all the refrigerant needs to be removed before you can open the system & fix, the connections. Don't even think of using compressed air, to check for leaks, nitrogen mixed with refrigerant is the standard way to pressurize a system when looking for leaks,. Whatever you do, you will need a vacuum pump, gauges, a crash course on how to evacuate and charge the system. The most accurate way is to weigh in the refrigerant, but almost nobody does.

134A, actually, all refrigerants mix with the oil for the compressor, but when it leaks the oil looks like alien autopsy blood in color. I believe Ford started using it in 94 so you may have a converted system

The cycling is because it's most likely low on refrigerant. A low pressure switch is opening the circuit to compressor

There's lots and lots of YouTube instructions out there on how to do it. But It may be cheaper if you just fix the leaks and have somebody else evacuate and recharge AC system. At least you found your leaks my system on the truck I just picked up last month leaks out in two days and I can't even find a trace of oil yet but I haven't really spent any time on it.
Sooooo... I bought a ’92 Ranger Custom (4.0/A4LD/4x4) over the winter. The PO claimed that the A/C worked great (as with everything else he said, a total lie). We’ve had some unseasonably warm weather lately, after a winter that seemed to last forever, so I tried it out.

No cold air whatsoever was forthcoming. I already know that there are leaks in the A/C system, due to this sight welcoming me under the hood:

https://drive.google.com/file/d/18-AkRGC12Py6TODiqfivkW1lg5EEZZu3/view?usp=sharing

https://drive.google.com/file/d/1mXf_BiG6cRs1Z3v-ZxaBbOn70lxfnrBq/view?usp=sharing

Each of the spots I’m pointing to in the pics have green fluid leaking from them.

Additionally, I turned on the A/C in the truck and got out to see what the A/C pump was actually doing. As it happens, the pump cycles on for just about exactly 1 second, then turns off for 5 seconds, and starts the process all over again. It’s very precise in the timing. So my questions are as follows, if anyone can help out:

1. What is up with the cycling on and off of the A/C compressor? Is it detecting that there are leaks due to pressure loss and switching itself off in order to keep from burning up or something?

2. Is it possible to replace the o-rings that are causing the leaks in the system, then recharge the A/C? What’s involved?
I’ve always done all my own mechanic work, but A/C is a bit of a mystery to me (most of my vehicles never had it).

Any help is VERY much appreciated!!!! :icon_thumby:


PS - If anyone can enlighten me on how to embed photos within the text of a thread (rather than hyperlinks, as I’ve done here), it would REALLY help me out!!!
 
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adsm08

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Mostly what Denise said.

I have always been told that R134a does not mix with its oil like most other refrigerants, and that instead is has to push the oil through the system. That is why sight glasses aren't generally used on 134 systems like they were with R12. This makes getting the charge correct much more important, and so using just pressure to charge it, rather than weight, is a very bad idea.

It doesn't cost much to get the system evacuated and recharged at a shop, most of the cost should be refrigerant, which you will have to buy anyway. I bought a 30lb can last summer when I had a lot of AC work to do, got a good price on it (better than most shops get), and it still works out to about $3.50 a lb.
 

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Lessee.. 12 ,22, 404a, 409, 410a, And a few others in the shed, completely out of 134, bummer! Adsm you're probably right about the oil but I've never particularly like Automotive Systems anyhow, and I really don't like working with 134 without gloves lol
Mostly what Denise said.

I have always been told that R134a does not mix with its oil like most other refrigerants, and that instead is has to push the oil through the system. That is why sight glasses aren't generally used on 134 systems like they were with R12. This makes getting the charge correct much more important, and so using just pressure to charge it, rather than weight, is a very bad idea.

It doesn't cost much to get the system evacuated and recharged at a shop, most of the cost should be refrigerant, which you will have to buy anyway. I bought a 30lb can last summer when I had a lot of AC work to do, got a good price on it (better than most shops get), and it still works out to about $3.50 a lb.
 

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Yeah, my plan was pretty much to try to fix the leaks myself and pay someone else for the evacuation part. I assume that the system needs to be evacuated prior to repairs...

...any idea how successful people are with fixing leaks of this type? I assume it would just be replacing o-rings... or, not? Finally, I have a can of A/C Pro, but I’m kind of thinking that if the system is completely drained, it will have to be refilled professionally instead, no? Sorry, I have just about no experience with A/C, even though I’ve always done all of my own mechanic work.

Thanks!
 

Denisefwd93

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Yeah, my plan was pretty much to try to fix the leaks myself and pay someone else for the evacuation part. I assume that the system needs to be evacuated prior to repairs...

...any idea how successful people are with fixing leaks of this type? I assume it would just be replacing o-rings... or, not? Finally, I have a can of A/C Pro, but I’m kind of thinking that if the system is completely drained, it will have to be refilled professionally instead, no? Sorry, I have just about no experience with A/C, even though I’ve always done all of my own mechanic work.

Thanks!
ther trouble with refrigerants for pressurizing .. is they only make pressure equal to temp.. unless they are moving in the system (being compressed and evaporating) So a hot day is better then a cold day. Soap bubbles are still one of the best ways to find leaks.
 

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So I found an A/C o-ring set on LMC for a fairly reasonable price (10 bucks). I have a few questions, however:

1. Is it possible to tell if the other components (condenser, accumulator, etc) are functional prior to replacing the o-rings?

2. Is there any way to tell if the refrigerant/oil mixture needs to be evacuated prior to replacing the o-rings? I’m assuming that the standard procedure would be to pay someone to evacuate the system, then replace the o-rings, then pay someone to refill the system. I’m just thinking that perhaps the refrigerant/oil mixture has leaked out, therefore making evacuation an unnecessary expense...

3. I have a can of A/C Pro kicking about that I’d like to try to use to recharge the system, after the o-rings have been replaced. Is this a possibility, or does oil need to be added at the same time?

Sorry I’m so in-the-dark on this topic. Thanks for any help!
 

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I'm not the one to answer all your questions. But....

There are Schrader valves (just like your tire stems) for filling, testing and evacuating the system. You can quickly bump the little stem in one of those and if you hear "pssst" then there is still some pressure in the system.

Also, on the inlet(?) of the evaporator coil ( that's the part that your cab air blows over to get cold) there is an orifice and screen. If you open the system to replace o-rings, you should inspect or replace the orifice. If the screen on the orifice is full of garbage, then chances are you compressor has failed and the evaporator coil may be clogged with similar garbage. When ordering the orifice, there are fixed ones and adjustable ones. You probably need a fixed orifuce. But don't rely on my word for that.

A/C systems are finicky about being clean and having the proper amount of oil and refrigerant. So, if in doubt, get help.

Sent from my SM-G960U using Tapatalk
 

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Take your can of ACscam and throw it away. Do not use that crap unless you have a vacuum pump to properly evac the system, and a scale to measure what is going it.

Also, oil should be added just prior to charging.

It is likely that your system is empty, so tap a valve and see that it is, then just start popping lines off.
 

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I can of AC Pro is not enough to fully charge your system that's empty.

If you add oil the chances are you will have too much oil!

so unless you know how much oil is in there don't add more! I know it's tempting because they sell the dye with the oil.

If you knew how to use gauges, nitrogen, and refrigerant to purge and evacuate you could tell what's what, but without proper gauges and vacuum pump all you can really do is disconnect replace the O-rings and put a "holding charge" in it and take it to a professional.
 

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All of this is great advice. Thanks, everyone!

Out of curiosity, is the evacuation/recharge something that an average mechanic shop can do, or does it require some kind of specialist? Hard to believe that I’ve never had it done before, but, well, there it is...
 

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All of this is great advice. Thanks, everyone!

Out of curiosity, is the evacuation/recharge something that an average mechanic shop can do, or does it require some kind of specialist? Hard to believe that I’ve never had it done before, but, well, there it is...
most automotive shops evacuate and recharge air conditioning it's probably part of their bread and butter customer base.

I literally hate Automotive Systems.

I've been in & around heating and air conditioning business my whole life.
 

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m

I literally hate Automotive Systems.
Auto AC isn't that bad. I'm sure it isn't as durable as a fixed location house unit, but it isn't that bad once you are used to it.

I am about done pissing with this mini fridge I was working on. I thought I had it fixed, it got cold inside and everything. Checked on it a day later because it didn't seem cold enough inside. Compressor was hot to the touch and the low side was under vacuum.
 

Denisefwd93

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Auto AC isn't that bad. I'm sure it isn't as durable as a fixed location house unit, but it isn't that bad once you are used to it.

I am about done pissing with this mini fridge I was working on. I thought I had it fixed, it got cold inside and everything. Checked on it a day later because it didn't seem cold enough inside. Compressor was hot to the touch and the low side was under vacuum.
Refrigeration pressures are very different from Air Conditioning, very different, the evaporator actually has to be well below zero.
Check the specs on the name plate or sticker. charge is probably under 5 ounces and yes the compressor is supposed to be very hot when it runs on these little refrigerators. Start up suction pressure should be under 5 lb and get close to zero as it gets colder inside but if it stops cooling there's a good chance you have moisture in the capillary tube. Hopefully you have a strong vacuum pump. Just one hose from your gauges holds about 3 oz lol.

Does it use 134A?
 
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So my A/C compressor face plate is now not engaging at all. I removed the plastic caps from the high and low-pressure check fittings and gently pressed down on the ball bearing inside. Got a slight “pffff” out of each (both when the truck was running with the A/C turned on and when it wasn’t). Seems like the pressure is really low in the system. Therefore, I’m kind of thinking that it would be okay to just order the new o-ring set from LMC, start replacing them, then have a shop refill the system and hope for the best. Anyone disagree? Are there any tests that can be performed on the compressor, condenser, TEV, etc or does one just have to pay for the system to be charged and hope it works?

Thanks!

PS - I’ve never had a shop evacuate and refill an A/C system before. I’m anticipating that it will be a couple hundred bucks?
 
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