Air Conditioning Trouble Shooting

[XJRob2]

Here's another "cool" tidbit - Properly evacuated, a vehicle system will usually draw in nearly a full charge of freon from the high pressure port with the system OFF.

Of course, don't leave anything except a gauge connected to the high pressure side while running.

Yes, it's that time of year again and there will be plenty of AC questions to go around. Anybody reading this thread should google and learn all they can about freon AC. It's fairly simple to understand and troubleshoot once you know the theory of operation.

You are right about the charging from the high side while in vacuum. Also it will take the charge as a liquid.
For those of you worried about high pressure mess with a system that runs 410a. I am a HVAC service tech, and there is a lot more to this stuff than just adding freon to a system.

 

[Johnny O.]

I am assuming that meant R-12?
I didn't think that R-22 was used in auto's. I have a 90 XJ, and was thinking there is R-12 in it.

Yep. That’s what I meant. I did most of my work on homes, that’s why I have that R-22 stuck in my head. I never meet a car that used R-22

 

[kennzz05]

ditto on the 410a the first time i hooked up to it i expected my gauges to start popping (hoses) hvac tech also 30 years. recently retrained to be an over the road truck driver i know i know whats this got to do with ac??? nothing, sorry

 

[XJRob2]

I am going to my local NAPA and see if they stiff carry hotshot-12 which is supposed to be a much cheaper drop-in replacement for r-12. I will reply here as soon as I find out for sure.

 

[splitz]

Ok, I tried again with what was left in the can. I started filling it up, and the gauge wasn't moving very much. So I cut the engine off, and I start hearing this hissing noise. It is hard to tell where it is coming from, but it sounds like the compressor.

 

[Rick Anderson]

Front Shaft Seal on the compressor is usually the first to go. Its hard to see, behind the clutch, look for some leaking AC oil.

R-22, I "believe" is stationary refrigerant, for homes and business. I "think" they do use it in some of the auto refrigerant blends, like Freeze-12.

Charging with a vacuum on the system and the compressor off, of course you can charge to any port as liquid if you desire. The lower the pressure the faster the liquid refrigerant boils into a vapor. Although illegal, if you've ever seen a can of refrigerant opened up to the atmospheric pressure, just imagine opening it up to a vacuum, the stuff instantly flashes to a vapor.

 

[splitz]

So that sounds like a job for a pro...grrr this $2600 jeep keeps getting more and more expensive!!!

 

[XJRob2]

So that sounds like a job for a pro...grrr this $2600 jeep keeps getting more and more expensive!!!

Mine was $800.00, and it costs to keep up too, but still love it.

I went to the local NAPA today, and got the Freeze12 upfit kit to the sum of $25.00 including one can of the stuff. I added it to the system, and whala........nice cold a/c.
There was also a kit to change over to 134a for about $40.00 with everything needed, but I don't think the 134a will cool as well with the existing (smaller) coils that were designed for r12. Maybe that is just me though.

 

[splitz]

Anyone know how much replacing the Front Shaft Seal goes for?

 

[Rick Anderson]

Most AC Compressors, rebuild or replacement of parts on/in the compressor is a professional job.

BUT, I have spoke with more than one person that have replaced the front shaft seal on a compressor themselves without totally rebuilding the compressor.

I'm sure that depends on the compressor, some have a front shaft seal that is easily replaceable and others need a total tear down. But it might be worth it, to do a little research and see if you can replace that front seal.

If you have to tear down the compressor, you might as well just get a rebuilt compressor and replace it. You'll need to get a filter/drier as well, and vacuum down the system before servicing. You probably have been losing oil out that leak, so, when replacing the oil that will be lost in the component replacement (there are usually guides in the manuals as too how much oil to add for each component replaced) you may want to add an extra once or two on top of those figures, because the systems probably been leaking a while losing oil with the leak and is lower than normal on oil level.

 

[1bolt]

Mine was $800.00, and it costs to keep up too, but still love it.

I went to the local NAPA today, and got the Freeze12 upfit kit to the sum of $25.00 including one can of the stuff. I added it to the system, and whala........nice cold a/c.
There was also a kit to change over to 134a for about $40.00 with everything needed, but I don't think the 134a will cool as well with the existing (smaller) coils that were designed for r12. Maybe that is just me though.

This is an interesting question, does anyone know the answer? is Freeze12 just the same "R134a retrofit" stuff with a different branding?

 

[EMSJEEP]

BTW, its illegal to service an AC System with a known leak, unless you at least attempt to repair the leak...

Tell that to my dealership, they wouldn't believe me or fix the leak, just sent me home saying "its cool now, but theres a leak and we can't find it, good luck."

 

[Rick Anderson]

Just adding dye to the refrigerant is considered by some enough to attempt to find and solve a leak, thus they are covered if thats all they do.

I have actually solved a slow leak in one of my vehicles by simply tightening up all the fittings in the AC system. There is a lot of wriggle room in the stipulation to "at least attempt to repair the leak". I could easily see some more surly shops blowing off the requirement completely, a dealership that has a surly service department is NO Surprise at all.

Freeze12 is NOT the same as R-134a retro-fit. R-134a is NOT compatible with R-12 oil, and it should be changed out with a compatible oil.

Freeze12 is a "BLEND" of several different refrigerants, the blend gives you performance that is closer to R12 than R134a is. BUT, it does have some draw backs. Just like when you boil a mixture of water and alcohol, the alcohol boils off first leaving the water behind, the same thing can happen with these refrigerant blends. So if you have a leak in the AC system, it is likely the "BLEND" will change drastically as it leaks, since the refrigerant with lower pressures of evaporation will leak out first.

Even worse in the case of Freeze12, since it uses mostly refrigerants that cannot MIX with R12 oil, it uses some propane/hydrocarbon refrigerant to serve that purpose. If you have a leak, the first refrigerants of the "BLEND" to leak out will be the propane/hydrocarbons leaving enough pressure for the AC system to continue to work, but NOT enough propane/hydrocarbon to circulate the oil and the system can be damaged from lack of lubrication.

Freeze12 may perform well, but it does have it draw backs, I definitely would NOT use it in a leaky system that you have top off from time to time.

 

[MudDawg]

Sounds like Rick Anderson knows his way around a gauge set.:thumbup: I'll just add a couple of things. R-22 has never been used as a factory automotive refrigerant in any american car...(unless there was some obscure usage)...the hi side pressure and temp will take it past critical.....generally speaking 1990 and older cars use R-12...newer cars use R-134a...(Some manufacturers jumped on the 134 bandwagon early)....R-410a was also mentioned....not applicable to automobile A/C service....uses POE oil and runs a MUCH higher head pressure than even R-22....I see head pressures of 380+ in super high efficiency central systems...if these were in cars, with the limited condenser area...it would easily go past tubing failure pressure...

 

[XJRob2]

bandwagon early)....R-410a was also mentioned....not applicable to automobile A/C service....uses POE oil and runs a MUCH higher head pressure than even R-22....I see head pressures of 380+ in super high efficiency central systems...if these were in cars, with the limited condenser area...it would easily go past tubing failure pressure...

Dern right 410a has high pressures and is also a mixed type of gas.
As far as being "illegal" to service a system without fixing a leak, I have to say that is wrong. Atleast in hvac repairs. I have also never heard of that law here for auto mechanics.There is a certain rate/amount that has to be leaking to be illegal. It IS good business and enviromentally consious to repair them all if possible.
I don't know exactly why cars would be different as far as leaks go. I think the epa just wants to charge more and uses the enviroment as a scapegoat to some degree. I may be wrong, and it wouldn't be a first. I do however have some experience in the hvac world. :eeks1:

 

[Rick Anderson]

I just did a quick search and found nothing from the EPA stating you must at least attempt to repair any leaks before servicing.

There was some stipulations about the rate of leak and total leakage before repair is necessary, but it was in the Stationary section.

I must have confused the regulation stating you can NOT intentionally release refrigerant into the air. If you continue to service a known leaking system, are you NOT doing exactly that? But the reg doesn't say that, I guess some people just interpret it that way.

 

[XJRob2]

The newer freons are supposedly "enviro friendly" which one would think could be vented. I would not recommend it, as there is a hefty fine that could come from it if caught. And I do mean a hefty fine. :shiver:

 

[Rick Anderson]

The old refrigerants had chlorine in the molecule, which was devastating to Ozone (thats Ozone, NOT the Ozone layer, which is still very debatable if it was hurting the Ozone layer or if the Ozone layer was ever depleting). They were classified as OZONE DEPLETING.

The new HFC refrigerants are classified something like Ozone Damaging, or something to that effect. They are not nearly as damaging to ozone, but I guess they can hurt some.

All the rules are the same for all refrigerants, well I guess official refrigerants that have an EPA designation, you can't vent them into the air, if you need to remove them it has to be recovered with machinery and turned in for recycling, etc.

The only difference is, the old Ozone Depleting Refrigerants have been banned from production, you can still purchase from the existing stocks, which is re-cycled so it will be available for years to come. Its sale is also restricted to licensed techs only, thats why you don't see R-12 for sale anymore in the retail stores. You can only find it at Pro-Supply Shops and have to present a license for them to sell it to you.

 

[Mudweiserjeep]

I have a 87 XJ that the AC is not working. I have been reading this thread and others....reading on the net to repair my system and convert it to the 134a. I have been looking at this setup: http://www.id-usa.com/product_landing_ac.asp
Reading the instructions it says to take the vehicle to a shop to have the old coolant recovered. I figure mine has leaked out....not sure if any is still in there. If I was to want to get the remaining coolant out myself...How would I do this? Can you open one end of it and use an air compressor to blow the systen clear?

Just thinking in and out of the box here. :compwork:

 

[Shorty]

The newer freons are supposedly "enviro friendly" which one would think could be vented. I would not recommend it, as there is a hefty fine that could come from it if caught. And I do mean a hefty fine. :shiver:

MUDWEISERJEEP^
it's no joke- all it takes is one A-hole neighbor with an axe to grind and a cell phone/camera to get you into a world of poop!
that being said, unless you jeep on the moon, the system will only leak down to equal pressure with the air around you (atmospheric pressure) and the remaining refrigerant will still be in the system and along for the ride until you vacuum it out. Your best bet is to pull a vacuum and verify it holds-- this will remove any questionable refrigerants and boil off any moisture that has entered the system in the last 20 years, change your receiver/drier, and recharge with your choice of refrigerants and a compatible oil.
To evacuate and pull vacuum, I use a local AC shop that only charges me the hourly labor rate for AC work and perform the necessary nuts-n-bolts work and recharge myself-- much cheaper in the long run:spin1:
--Shorty