Air vents smoking
05-08-2016, 09:52 PM
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Air vents smoking
I have a 91 Firebird 3.1L, and when I turn my A/C on smoke starts to come through the air vents after a few minutes. Im not really sure where to start to try looking to fix this problem. I live in Las Vegas and summer is coming up really fast. Im hoping some of you will have some suggestions so I can get this fixed before the 115 degree temps get here. Please help
05-09-2016, 08:21 AM
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Re: Air vents smoking
If it has no smell, it's not smoke; it's water vapor.
Most likely cause of that is, the evap is too cold, because the system is low on refrigerant. It's freezing. That happens slowly and incrementally: the first few inches of tubing get too cold because the pressure is too low and the gas is moving too slow, and water freezes out of the air onto it instead of merely condensing to a liquid, and a small section of the evap gets covered with frost; the frost is an EXCELLENT insulator, so that section of tubing gradually quits exchanging heat with the outside world; the next incremental section of tubing gets the supercooled gas at the below freezing temp still, and slowly does the same thing; over a period of time the entire evap gets covered in ice; and pretty soon the whole thing quits working. Sometimes it even blocks the air flow completely off. Good troubleshooting hint is, if you let it run like that for awhile, then turn the AC off but the fan on high, and LOTS of water comes dripping out of the drain and the air coming out of the vents smells REAL wet (oughtta be kinda obvious in Vegas), then that's whats going on.
As said, most common cause (the most common thing that happens to an AC system for that matter, even more common than working right) is that the refrigerant has leaked out and it needs a recharge.
Most likely cause of that is, the evap is too cold, because the system is low on refrigerant. It's freezing. That happens slowly and incrementally: the first few inches of tubing get too cold because the pressure is too low and the gas is moving too slow, and water freezes out of the air onto it instead of merely condensing to a liquid, and a small section of the evap gets covered with frost; the frost is an EXCELLENT insulator, so that section of tubing gradually quits exchanging heat with the outside world; the next incremental section of tubing gets the supercooled gas at the below freezing temp still, and slowly does the same thing; over a period of time the entire evap gets covered in ice; and pretty soon the whole thing quits working. Sometimes it even blocks the air flow completely off. Good troubleshooting hint is, if you let it run like that for awhile, then turn the AC off but the fan on high, and LOTS of water comes dripping out of the drain and the air coming out of the vents smells REAL wet (oughtta be kinda obvious in Vegas), then that's whats going on.
As said, most common cause (the most common thing that happens to an AC system for that matter, even more common than working right) is that the refrigerant has leaked out and it needs a recharge.
05-09-2016, 03:50 PM
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Re: Air vents smoking
If it has no smell, it's not smoke; it's water vapor.
Most likely cause of that is, the evap is too cold, because the system is low on refrigerant. It's freezing. That happens slowly and incrementally: the first few inches of tubing get too cold because the pressure is too low and the gas is moving too slow, and water freezes out of the air onto it instead of merely condensing to a liquid, and a small section of the evap gets covered with frost; the frost is an EXCELLENT insulator, so that section of tubing gradually quits exchanging heat with the outside world; the next incremental section of tubing gets the supercooled gas at the below freezing temp still, and slowly does the same thing; over a period of time the entire evap gets covered in ice; and pretty soon the whole thing quits working. Sometimes it even blocks the air flow completely off. Good troubleshooting hint is, if you let it run like that for awhile, then turn the AC off but the fan on high, and LOTS of water comes dripping out of the drain and the air coming out of the vents smells REAL wet (oughtta be kinda obvious in Vegas), then that's whats going on.
As said, most common cause (the most common thing that happens to an AC system for that matter, even more common than working right) is that the refrigerant has leaked out and it needs a recharge.
Most likely cause of that is, the evap is too cold, because the system is low on refrigerant. It's freezing. That happens slowly and incrementally: the first few inches of tubing get too cold because the pressure is too low and the gas is moving too slow, and water freezes out of the air onto it instead of merely condensing to a liquid, and a small section of the evap gets covered with frost; the frost is an EXCELLENT insulator, so that section of tubing gradually quits exchanging heat with the outside world; the next incremental section of tubing gets the supercooled gas at the below freezing temp still, and slowly does the same thing; over a period of time the entire evap gets covered in ice; and pretty soon the whole thing quits working. Sometimes it even blocks the air flow completely off. Good troubleshooting hint is, if you let it run like that for awhile, then turn the AC off but the fan on high, and LOTS of water comes dripping out of the drain and the air coming out of the vents smells REAL wet (oughtta be kinda obvious in Vegas), then that's whats going on.
As said, most common cause (the most common thing that happens to an AC system for that matter, even more common than working right) is that the refrigerant has leaked out and it needs a recharge.
There is a slight smell to it, and it smells a little like refrigerant.
05-09-2016, 03:51 PM
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05-09-2016, 03:51 PM
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05-09-2016, 05:54 PM
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Re: Air vents smoking
Possible damaged evaporator especially if you only see the "smoke" when the AC is on and has a refrigerant smell.
05-31-2016, 02:15 PM
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Re: Air vents smoking
I know its been a while but heres an update: My A/C was fully charged and there are now cracks or anything broken that I can see. I let my A/C run on high for about 10 min and the vapor stopped coming out of the vents. Vapor no longer comes out of the vents when I turn my A/C. Which is great sense its starting to hit the triple digits now. Thanx everyone for your advice
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