Need Help From A/C Guys.

[Autobot]

Thanks to TDR for the recent help with #@$%! Fan Clutch. (2006 3500 Mega Cab) Anyway, condenser is leeking also. There is a visible place where I can see the "green stuff" bubblin out slowly. I called the local shop I use to see if I can buy part and replace (save money) and then have them recharge it. Shop guy said I should replace the Dryer aka Evaporator and the Expansion Valve aka orifice tube if I open the system to replace the Condenser. Can anyone chime in to tell me why this might be necessary and if it really is? If so I'll be spending an additional $137!

 

[Sean Flanagan]

I am not a real A/C guy but I just went through this repair. You need to replace the evaporator canister because it is probably saturated from the AC loosing it's charge. If you don't do this there is a good chance you will have to do it later and pay for another evacuate/recharge. The orfice tube is optional, but it is relatively low cost so replace it as cheap insurance. It can get plugged if the compressor fails. Good luck

 

[sag2]

As long as it has not/will not be open to the atmosphere for very long there is no need to replace it. If it has all leaked out and has been open for days then change the drier only. If nothing has come apart in the system there is no need to replace the orfice tube.

 

[B.G. Smith]

To make sure we are on the same page, the condenser is in front of the radiator, the evaporator is inside the truck under the dash, the receiver/dryer is under the hood near passenger side rear of engine. If the condenser is all that is leaking, you can probably get by with just replacing it but if the truck is more than a couple of years old then you should replace the receiver dryer. The dessicant in the dryer is there to trap any moisture or debris in the system. Some/most suppliers won't warrant the evaporator unless you change the receiver/dryer. If the orifice tube is in a connection in the line I would replace it, if it is in the hose requiring hose replacement I would think about it for a while. bg

 

[jelag]

The old dryers used to have a descant in the dryer to absorb water... . water in the system will freeze in the orfice tube and stop the system until it warms up and melts. . I don't know if today's systems still have descant... Today the system is so much better. . also if you can leave the vacuum pump on the system for several hours or overnight the vacuum will cause the the water to evaporate off (lower pressure lower boiling point).

I've had several open in the past few years... all the new 134A or what ever its now called... and have just left the vacuum pump on the system and came back the next day and charged it... If the orfice tube is good now there's no reason to change it. . as a speck of dirt from opening and closing the system will clog the old one or new one... .

On the other hand once the condenser is replaced, and the tube isn't clogged I'd go ahead and charge it back up... .

But I always go under the belief that if its not broken when it comes apart it goes back together with the part... I've been bit a few times but not very many...

Hope this helps. .

 

[RAB]

Its always a good idea to replace your accumulator/reciever drier when you open the system. It can make a difference in the temp of air you get out of the vents. Also it is a filter that can cause a blockage leading you to replace it sooner than later. Anytime I am changing a component that I have to open the system I replace the accumulator/reciever drier.

 

[RVTRKN]

The old dryers used to have a descant in the dryer to absorb water... . water in the system will freeze in the orfice tube and stop the system until it warms up and melts. . I don't know if today's systems still have descant... Today the system is so much better. . also if you can leave the vacuum pump on the system for several hours or overnight the vacuum will cause the the water to evaporate off (lower pressure lower boiling point).



I've had several open in the past few years... all the new 134A or what ever its now called... and have just left the vacuum pump on the system and came back the next day and charged it... If the orfice tube is good now there's no reason to change it. . as a speck of dirt from opening and closing the system will clog the old one or new one... .



On the other hand once the condenser is replaced, and the tube isn't clogged I'd go ahead and charge it back up... .



But I always go under the belief that if its not broken when it comes apart it goes back together with the part... I've been bit a few times but not very many...



Hope this helps. .

And to add a little, put a drop light on the accumulator where the drier is to heat it up when evacuating the system. (pulling a vacuum) It will help boil off any moisture, if there is any present.

 

[mwilson]

I'm with Sag2 on this one. If it still has pressure and has not been run empty you are fine.

A couple of things that do have to done with the R134A systems is a long vacuum time as Jelag does and put exactly the correct amount of refrigerant that is specified. In the R-12 days if you wanted a colder system you could put a little more in, but not the case with the R134A.



I broke down and bought my own gauges and vacuum pump a couple years ago and keep a tank of R134A on hand at the house. Buy a 30lb. cylinder in the fall when the prices drop and throw it on the shelf for the next summer.

I wish I had done it sooner as now I know that it is done correctly. With 4 vehicles, 2 of which are old, I have no shortage of a/c work at my place... . :-laf



For those of you already doing your own A/C work my ThermoKing techs have taught me to refill with the cylinder inverted (liquid fill) as they say R134A is a mix of chemicals and if you try to charge with the cylinder upright then the proper mix does not dispense. System will not work right. I changed to the liquid method and I think that they are right on. Much colder air from the evaporator even on my older stuff.



If you do try the liquid fill with vacuum in the system, pay attention as 2lbs of R134A will go in some kind of quick... ... ... ... ... ...

 

[sag2]

I liquid fill also, but be VERY careful to let the system sit for a while before you turn on the compressor. Failing to do so can cost you a compressor when it ingests a slug of liquid that does not compress very well!

 

[tempforce]

if you can get a condenser with a larger capacity, that will fit in the same place. do it. you will get better performance from the a/c system. also don't take a chance, change the oriface and drier. the parts are cheap compared to the labor.

cc

 

[madmanmanick]

A couple of things to think about with this. First off, if you are going to have the system open for a while then it would be a good idea to replace the dryer. The reason for this is when water mixes with refrigerant it becomes acid. That acid will eat at your o-rings and seals. I also agree with Jelag that water can also freeze and clog your system. The next thing you should do is go get a vacuum pump, gauge manifold set, and 30 lb cylinder of refrigerant. Then after you have completed your system repairs draw it down to a deep vacuum(as close to 30" as possible, hold this pressure for 12hrs), this will get any moisture and air and non-condenseables out of the system. Now if you pull the system to a deep vacuum, DO NOT!!! LIQUID CHARGE!!!. I can't stress that enough. To liquid charge a dry system under deep vacuum will more likely than not crack a line or the evaporator. Always wait until the system is above 0 psig and then you can start putting liquid if you feel that you can't wait for vapor. A friendly suggestion that if you evacuate the system add a 10 oz can of refrigerant oil to the system. This will help preserve your o-rings and seals, as well as the lifespan of your compressor. Hope all this was helpful.

 

[RVTRKN]

DO NOT!!! LIQUID CHARGE!!!. .

You must charge liquid due to the azeotropic refrigerant 134a, there are three different refergerants in 134a that boil off at three differant pressures and removing only the gas will cause the refrigerant to start to boil off when the pressure starts to drop. This will allow the frist refrigerant with the highest boiling point to boil first then as the temperature drops the next lowest boiling point refrigerant starts and so on. This will cause the refrigerant to have an improper mix of refrigerant and ruin the #30 bottle of 134a. If you want to protect from liquid boiling (causing exteeme cold), then you need to install an atomizor to the bottle before charging.

For those of you already doing your own A/C work my ThermoKing techs have taught me to refill with the cylinder inverted (liquid fill) as they say R134A is a mix of chemicals and if you try to charge with the cylinder upright then the proper mix does not dispense. System will not work right. I changed to the liquid method and I think that they are right on. Much colder air from the evaporator even on my older stuff.

If you do try the liquid fill with vacuum in the system, pay attention as 2lbs of R134A will go in some kind of quick... ... ... ... ... ...

Correct but add the atomizer to the bottle when charging liquid, if you slowly crack open your gages when charging liquid, the gage set will help atomize the refrigerant for you and then no need of an atomizer, as well as prevent what madmanmanick has described, even though I have never heard of it. Also you will open only the high side of the gage set, sending the liquid to the condenser and before the orifice tube allowing the refrigerant to expand before entering the low side of the system. The trick will be to allow as much as possible, as slow as possible. If the expanding refrigerant reaches the same pressure as the bottle is at, you will have to pull the rest in with the low side while running the system. So be quick about it but as careful as possible. There is a reason why an experienced tech should perform the repair. Good luck in your repairs and pay attention to what you are doing and you will be fine.



As I have noted in the past, auto AC is different than a home AC, and I will not work on auto systems, except for my own. I have performed this very procedure on my 94 gasser and never had any problems. I had to find the leak in the evaporator without being able to see it, and then replace it and go through the procedure I have described. It was opened to the atmosphere for a little time having a large leak and by adding a drop light to the accumulator where the drier is located, it dried it out, I did not replace the orifice and the accumulator. The truck is still cooling just fine 9 years after the repair. I know the person who bought my gasser in 04.

 

[mwilson]

Sorry, forgot to mention to crack the valve slowly.



Nice explanation by the way, RVTRKN.