A/C Guru's have a question?
09-23-2010, 08:04 AM
#1
A/C Guru's have a question? Guys,
I recently redid the entire A/C on my wife's suburban due to a compressor going bad, got lucky as I caught it before it dumped crap in the lines. Replaced compressor, dryer/accumulator, orifice tube, seals, flushed all lines and had a shop pull a vac and add the appropriate amount of R134a. I was supprised at how easy it was and now I want to turn my attention to my T/A. The A/C works fine and blows fairly cold but not really cold and like any typical older car the freon charge slowly leaks over a period of a year or so. I'd like to do some maintenance on her as I have read it's best to replace the dryer on most cars after about 4 years and since this car is 15 years old now would it be worth it? I was thinking of running some dye in it to see where I might have leaks and then replacing the dryer, seals and possibly the expansion valve (no orifice tube this year) to update the system. Also, can you drain the compressor oil to add fresh oil to the system? Then have a shop pull a vac and recharge the system. Is this a good idea or am I asking for more trouble? I'd like her to blow ice cold again, but not sure if I should even mess with it? Let me know what you think.
I recently redid the entire A/C on my wife's suburban due to a compressor going bad, got lucky as I caught it before it dumped crap in the lines. Replaced compressor, dryer/accumulator, orifice tube, seals, flushed all lines and had a shop pull a vac and add the appropriate amount of R134a. I was supprised at how easy it was and now I want to turn my attention to my T/A. The A/C works fine and blows fairly cold but not really cold and like any typical older car the freon charge slowly leaks over a period of a year or so. I'd like to do some maintenance on her as I have read it's best to replace the dryer on most cars after about 4 years and since this car is 15 years old now would it be worth it? I was thinking of running some dye in it to see where I might have leaks and then replacing the dryer, seals and possibly the expansion valve (no orifice tube this year) to update the system. Also, can you drain the compressor oil to add fresh oil to the system? Then have a shop pull a vac and recharge the system. Is this a good idea or am I asking for more trouble? I'd like her to blow ice cold again, but not sure if I should even mess with it? Let me know what you think.
09-23-2010, 08:17 AM
#2
If it ain't broke, don't fix it, BUT who ever listens to that?
Anytime you open the system up, you should replace the dryer/accumulator, the desiccant inside absorbs moisture quickly. IF you open it up, go ahead and replace the cheap stuff like you mentioned, the seals and expansion valve.
I would also remove the compressor to get the oil out of it. A general tip is to put the compressor in a vice and turn it over by hand or with a speed wrench to remove the oil. Some of them have drain plugs, some don't.
While those parts are out, pull the condenser out and make sure to flush it from back to front to remove all the trash inside the fins.
Whenever you are flushing the system, you cannot be too generous with compressed air to remove all of the flush agent. That stuff can do some serious damage to the ac system if left inside. I spent probably 2-3 hours with compressed air trying to remove all of the flush and dye agent from the condenser and evaporator. I didn't bother to flush the compressor. The hard lines are easy to flush as you can tip them and move them to make sure all of the flush agent is out, where it is a PITA to get it all out of the condenser due to all of the twists and turns. Same with the evaporator.
If any of your lines have mufflers in them, DON'T flush that component, either replace it, or do nothing with it. Some designs have internal baffling and vanes and is almost impossible to remove the flush agent.
Also, you don't need to take it to a shop, you could probably get a vacuum pump and manifold set from Harbor Freight for cheaper than a shop would charge. I have used those two tools from Harbor Freight, they were my boss' tools, and they worked great.
One last tip, make sure to get the proper weight of oil, I think it usually PAG46 or PAG150. Good luck!
Anytime you open the system up, you should replace the dryer/accumulator, the desiccant inside absorbs moisture quickly. IF you open it up, go ahead and replace the cheap stuff like you mentioned, the seals and expansion valve.
I would also remove the compressor to get the oil out of it. A general tip is to put the compressor in a vice and turn it over by hand or with a speed wrench to remove the oil. Some of them have drain plugs, some don't.
While those parts are out, pull the condenser out and make sure to flush it from back to front to remove all the trash inside the fins.
Whenever you are flushing the system, you cannot be too generous with compressed air to remove all of the flush agent. That stuff can do some serious damage to the ac system if left inside. I spent probably 2-3 hours with compressed air trying to remove all of the flush and dye agent from the condenser and evaporator. I didn't bother to flush the compressor. The hard lines are easy to flush as you can tip them and move them to make sure all of the flush agent is out, where it is a PITA to get it all out of the condenser due to all of the twists and turns. Same with the evaporator.
If any of your lines have mufflers in them, DON'T flush that component, either replace it, or do nothing with it. Some designs have internal baffling and vanes and is almost impossible to remove the flush agent.
Also, you don't need to take it to a shop, you could probably get a vacuum pump and manifold set from Harbor Freight for cheaper than a shop would charge. I have used those two tools from Harbor Freight, they were my boss' tools, and they worked great.
One last tip, make sure to get the proper weight of oil, I think it usually PAG46 or PAG150. Good luck!
09-23-2010, 05:10 PM
#3
If it ain't broke, don't fix it, BUT who ever listens to that?
Anytime you open the system up, you should replace the dryer/accumulator, the desiccant inside absorbs moisture quickly. IF you open it up, go ahead and replace the cheap stuff like you mentioned, the seals and expansion valve.
I would also remove the compressor to get the oil out of it. A general tip is to put the compressor in a vice and turn it over by hand or with a speed wrench to remove the oil. Some of them have drain plugs, some don't.
While those parts are out, pull the condenser out and make sure to flush it from back to front to remove all the trash inside the fins.
Whenever you are flushing the system, you cannot be too generous with compressed air to remove all of the flush agent. That stuff can do some serious damage to the ac system if left inside. I spent probably 2-3 hours with compressed air trying to remove all of the flush and dye agent from the condenser and evaporator. I didn't bother to flush the compressor. The hard lines are easy to flush as you can tip them and move them to make sure all of the flush agent is out, where it is a PITA to get it all out of the condenser due to all of the twists and turns. Same with the evaporator.
If any of your lines have mufflers in them, DON'T flush that component, either replace it, or do nothing with it. Some designs have internal baffling and vanes and is almost impossible to remove the flush agent.
Also, you don't need to take it to a shop, you could probably get a vacuum pump and manifold set from Harbor Freight for cheaper than a shop would charge. I have used those two tools from Harbor Freight, they were my boss' tools, and they worked great.
One last tip, make sure to get the proper weight of oil, I think it usually PAG46 or PAG150. Good luck!
Anytime you open the system up, you should replace the dryer/accumulator, the desiccant inside absorbs moisture quickly. IF you open it up, go ahead and replace the cheap stuff like you mentioned, the seals and expansion valve.
I would also remove the compressor to get the oil out of it. A general tip is to put the compressor in a vice and turn it over by hand or with a speed wrench to remove the oil. Some of them have drain plugs, some don't.
While those parts are out, pull the condenser out and make sure to flush it from back to front to remove all the trash inside the fins.
Whenever you are flushing the system, you cannot be too generous with compressed air to remove all of the flush agent. That stuff can do some serious damage to the ac system if left inside. I spent probably 2-3 hours with compressed air trying to remove all of the flush and dye agent from the condenser and evaporator. I didn't bother to flush the compressor. The hard lines are easy to flush as you can tip them and move them to make sure all of the flush agent is out, where it is a PITA to get it all out of the condenser due to all of the twists and turns. Same with the evaporator.
If any of your lines have mufflers in them, DON'T flush that component, either replace it, or do nothing with it. Some designs have internal baffling and vanes and is almost impossible to remove the flush agent.
Also, you don't need to take it to a shop, you could probably get a vacuum pump and manifold set from Harbor Freight for cheaper than a shop would charge. I have used those two tools from Harbor Freight, they were my boss' tools, and they worked great.
One last tip, make sure to get the proper weight of oil, I think it usually PAG46 or PAG150. Good luck!
On the vacuum and charge, you can rent a vacuum pump and gauges from autozone and do it all yourself. It costs $300 to rent but you get all your money back when you return it.
For what its worth, I would just do an evacuate and charge to make sure its full, if it hasn't leaked out a lot and blows fairly cold after several years I wouldn't really mess with it, and it never hurts to have a little dye in it for when a leak does occur. So a evac and charge with dye sounds good.
09-23-2010, 08:40 PM
#5
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any places that look oily such as the front seal on the compressor or any place where lines connect would be a good indicator of a leak with out dye. completely removing the condesor to clean it will work wonders for your a/c. the more heat you pull out with the condensor the colder the freon is in the evaporator.
09-24-2010, 06:42 AM
#6
Great advice, all GM is PAG 150 that I am aware of BTW.
On the vacuum and charge, you can rent a vacuum pump and gauges from autozone and do it all yourself. It costs $300 to rent but you get all your money back when you return it.
For what its worth, I would just do an evacuate and charge to make sure its full, if it hasn't leaked out a lot and blows fairly cold after several years I wouldn't really mess with it, and it never hurts to have a little dye in it for when a leak does occur. So a evac and charge with dye sounds good.
On the vacuum and charge, you can rent a vacuum pump and gauges from autozone and do it all yourself. It costs $300 to rent but you get all your money back when you return it.
For what its worth, I would just do an evacuate and charge to make sure its full, if it hasn't leaked out a lot and blows fairly cold after several years I wouldn't really mess with it, and it never hurts to have a little dye in it for when a leak does occur. So a evac and charge with dye sounds good.
09-24-2010, 07:48 AM
#7
If you are going to put new freon in the system, I would replace the accumulator at the minimum, that thing will absorb alot of moisture over 15 years. Plus, its only $40.
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09-24-2010, 07:54 AM
#8
Yup, I was tinking the same thing. Do you think the expansion valve will need replacing as well? I know on newer systems you always replace the orifice tube as it's cheap and easy but not sure on older systems about the expansion vavle?
09-24-2010, 07:56 AM
#9
I'm not near as familiar with expansion valves. If you had an orifice tube, I would say 100% to replace it, but I don't know if the expansion valve has any kind of filter media like an orifice tube does.
EDIT: After some quick googling, I would replace it for the $30, more so for the piece of mind. I would hate for the orifice to be over sized and not allow the proper pressure and volume of freon to flow through. If the pressure and flow are too high or too low, the freon will not be able to vaporize as efficiently, which may be what is happening in your current situation, hinting at why it may be inefficient by 5-6*F. There were also symptoms of them getting clogged, so some may have filter media in them.
EDIT: After some quick googling, I would replace it for the $30, more so for the piece of mind. I would hate for the orifice to be over sized and not allow the proper pressure and volume of freon to flow through. If the pressure and flow are too high or too low, the freon will not be able to vaporize as efficiently, which may be what is happening in your current situation, hinting at why it may be inefficient by 5-6*F. There were also symptoms of them getting clogged, so some may have filter media in them.
Last edited by 1SLwLS1; 09-24-2010 at 08:03 AM. Reason: adder
