AC is blowing hot air... diagnose?
So every Google search result basically says to recharge with AC Pro... but one result warned not to use this unless you actually know you have a leak (because putting something like that in your system that is designed to clog leaks can damage your car if you don't actually have a leak).
Without getting raped by a dealer, how can I tell if my AC is blowing hot air because I need a recharge? What other issues could it likely be, and how can I find out? Thanks in advance for your help! FYI: This is a constant warm air problem, not intermittently. |
First would be to check if the compressor is running
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Several reasons why this could be happening other than a leak. Diagnosing requires test equipment and knowledge. To avoid being raped by a dealer, I would get recommendations of a trustworthy indie. It's a Chevy, the A/C system is pretty much generic GM.
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You don't need a recharge unless you have a leak. They will need to check the pressure to see how much is there and then (most likely) do a leak check to find the component that is leaking. Repair cost will depend on the failed part such as compressor or condenser.
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Originally Posted by stingray71
(Post 1597405486)
You don't need a recharge unless you have a leak. They will need to check the pressure to see how much is there and then (most likely) do a leak check to find the component that is leaking. Repair cost will depend on the failed part such as compressor or condenser.
I got mine checked since it's been hot air only. They said it has NO Freon left in the system. It's either all burnt out or leaked. To find the leak, they have to fill it with NEW freon with dye that will show where the leak is. That's a $150 job. Finally, once the leak is determined, then the repair of that part will be another issue. The tech told me, since the car has low miles (35K), compressor & condenser are most likely not the problems, but the valves in the line - those are more prone to leaks. I am having the AC checked out at another shop next week....we'll see what happens! :willy: |
Originally Posted by Vette_Fan
(Post 1597449367)
Goodyear stores are having a special - Check AC for $9.95
I got mine checked since it's been hot air only. They said it has NO Freon left in the system. It's either all burnt out or leaked. To find the leak, they have to fill it with NEW freon with dye that will show where the leak is. That's a $150 job. Finally, once the leak is determined, then the repair of that part will be another issue. The tech told me, since the car has low miles (35K), compressor & condenser are most likely not the problems, but the valves in the line - those are more prone to leaks. I am having the AC checked out at another shop next week....we'll see what happens! :willy: |
Originally Posted by NDMIKE88
(Post 1597449458)
Maybe I'm old school but I never heard of Freon being "burnt out". I thought AC units were a sealed system and the only way to be low on Freon or no Freon is if you have a leak?
I think it's a leak too. Going to another shop to get the Freon FILLED with DYE to check the leak. Only then we'll know the actual location of the leak. |
Freon being burnt.
Freon contaminated by burnt refrigerant oil, and metal after compressor burns out. |
Originally Posted by HK770
(Post 1597449645)
Freon being burnt.
Freon contaminated by burnt refrigerant oil, and metal after compressor burns out. Hope not...:ack: |
One thing to check is the A/C fan belt for looseness or slippage.
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One issue's not been mentioned a possibility, also.
IF system checks-out w/ no leak(s) might very well be AC's working. If so there're 'curtains' directing air, it quit remaining closed instead of opening. When this happens there's no air flow hot or cold. Repairing this is a genuine PITA fixing curtains/doors. Dash must comes out for access to components for proper repair/replacement, then parts. Beaucoup labor hours, naturally. Let's hope it's only a leak. :cheers: |
Three things for hot air: 1) Leak 2) compressor 3) switch
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Originally Posted by corvette312
(Post 1597450722)
Three things for hot air: 1) Leak 2) compressor 3) switch
This worked for my Toyota. |
Originally Posted by Shaolin Crane
(Post 1597405164)
First would be to check if the compressor is running
More than likely the system has no/low pressure or, there is an issue between the A/C compressor and the A/C head unit (fuse, relay, etc) You can rent a set of A/C manifold gauges from most parts stores that rent tools to check system pressure. I know Autozone rents them out. With these you can check your system pressure both high and low sides and if your system has any pressure at all. There are many good videos on Youtube on how to do this. Once you understand the procedure it takes just a minute to do. |
And if you do recharge your system NEVER, EVER, EVER put anything in the system other than pure Freon (R134a in the case of the C6) or, pure Freon containing dye. NEVER use ANY freon with any stop leak additive! It can wreak havoc on your A/C system (particularly the compressor, evaporator and orifice tube) and, the recovery equipment used when if/when the system is ever evacuated for component replacement. That stuff can kill an evacuator machine, literally causing thousands of dollars in damage to the shop's equipment.
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Originally Posted by VtVette
(Post 1597451562)
^ this is the proper first step. If it comes on you might have an issue in the heater matrix behind the dash that is preventing the cold air from getting to the correct vent(s).
More than likely the system has no/low pressure or, there is an issue between the A/C compressor and the A/C head unit (fuse, relay, etc) You can rent a set of A/C manifold gauges from most parts stores that rent tools to check system pressure. I know Autozone rents them out. With these you can check your system pressure both high and low sides and if your system has any pressure at all. There are many good videos on Youtube on how to do this. Once you understand the procedure it takes just a minute to do. |
Most stop leak isn't really "stop leak" any more. Just a different velocity oil that treats o rings which typically cause the small leaks. Even older stop leaks would mever go as far ss the damage described because it would never make it past the orifice tube, rendering the system useless anyways
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If you don't know anything about how system works take to AC specialty mechanic. Some of the information offered and/or suggested is not credible. Could be many causes. It is not going to be diagnosed on this forum.
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Originally Posted by Shaolin Crane
(Post 1597451800)
Most stop leak isn't really "stop leak" any more. Just a different velocity oil that treats o rings which typically cause the small leaks. Even older stop leaks would mever go as far ss the damage described because it would never make it past the orifice tube, rendering the system useless anyways
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Step one is to make sure that the compressor clutch kicks in once you turn the A/C on.
Step two is to get gauges on the low and high side, and check for your pressures. The system has a high pressure switch, and if the pressure gets too high in the system as the Freon heats up, it will kick the system off so you don't blow a line. Note a orifice tube filter is will show up on the pressure test, with the high to low pressure way out of the norm. Now the ugly one, and that if the system has a leak. Hence if the system did a full leak out with no pressure in the system, it gets nasty real quick, since this induces moisture to the system, that can not only case rust in the system/parts, but clog the orifice tube filter as well. So even finding the leak to begin with to correct it, doing a vacuum draw on the system to pull all the moisture out of the system, you can still have rust in the system, and/or a clogged orifice tube filter as well. https://cimg5.ibsrv.net/gimg/www.cor...492a9ec779.jpg So on a system that you find way, way low on Freon, then the run down becomes to find the source of the leak to begin with to correct it, pull the system apart to check for rust/clean the system and change the orifice tube filter out if needed, vacuum the system to boil out any water in the system, then recharge the system with fresh Freon and oil. |
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