a/c problems - can anyone help
Jul 14, 2008, 09:31 AM
#1
a/c problems - can anyone help
alright all you lovely keyboard engineers out there...
I've verified that it's not coolant.
The smell emitting from my car was sourced from my cabin filter... (smelled like mildew and squash air freshener when you get up close to it... gross)
The current problem is described as this:
The a/c is functional for the first 20 minutes of the car running.
Once the car gets up to temp, the a/c compressor disengages and the a/c stops.
The a/c then never turns back on. Coasting from 3krpms and up have no affect on it.
Is that a sign of a faulty a/c compressor?
car: 2004 Evo8
I've verified that it's not coolant.
The smell emitting from my car was sourced from my cabin filter... (smelled like mildew and squash air freshener when you get up close to it... gross)
The current problem is described as this:
The a/c is functional for the first 20 minutes of the car running.
Once the car gets up to temp, the a/c compressor disengages and the a/c stops.
The a/c then never turns back on. Coasting from 3krpms and up have no affect on it.
Is that a sign of a faulty a/c compressor?
car: 2004 Evo8
Jul 14, 2008, 12:07 PM
#4
I'm wondering if it's the compressor's clutch (the pulley on the end of it that the belt turns it with). I know my base Lancer and the Evo probably have different AC compressors, but it would be worth looking into.
I had a similar problem a couple of years ago. Several mechanics couldn't find the problem until I tried the wisest and oldest one that I know. If you are able to see the AC clutch pulley with the engine and AC on, during normal functional operation it should move towards the compressor and away from the compressor, just slightly, every few minutes as it engages and disengages. What my mechanic noticed was that that the clutch would work when the car was first turned on, but wouldn't move after one or two cycles. I can't recall whether the pulley was being pushed out or in when it was engaged and disengaged, but it would do one of the two once and not move any more. He even took a pry bar, while the car is moving (don't try this at home kids), and moved the clutch pulley as it was turning and presto! the AC blew cold again, until it moved back to being disengaged.
Apparently this clutch is operated by an internal electro-magnet that can wear out over the years. If this ends up being the problem, I would recommend you to replace both the compressor and clutch together. The clutch on it's own normally costs 2/3 the price of a compressor and clutch together, if you can even find one. You'd probably need a new dryer too, since most places that sell new AC compressors won't warranty them without changing the dryer first (since the system will be open and exposed when the compressor is replaced). www.acpartsnow.com (aka brightauto) has them pretty cheap. That's where I got mine and haven't had any problems with it.
But anyways, take a look and see if the clutch is engaging and disengaging. It's easy to check and doesn't cost you any money.
I had a similar problem a couple of years ago. Several mechanics couldn't find the problem until I tried the wisest and oldest one that I know. If you are able to see the AC clutch pulley with the engine and AC on, during normal functional operation it should move towards the compressor and away from the compressor, just slightly, every few minutes as it engages and disengages. What my mechanic noticed was that that the clutch would work when the car was first turned on, but wouldn't move after one or two cycles. I can't recall whether the pulley was being pushed out or in when it was engaged and disengaged, but it would do one of the two once and not move any more. He even took a pry bar, while the car is moving (don't try this at home kids), and moved the clutch pulley as it was turning and presto! the AC blew cold again, until it moved back to being disengaged.
Apparently this clutch is operated by an internal electro-magnet that can wear out over the years. If this ends up being the problem, I would recommend you to replace both the compressor and clutch together. The clutch on it's own normally costs 2/3 the price of a compressor and clutch together, if you can even find one. You'd probably need a new dryer too, since most places that sell new AC compressors won't warranty them without changing the dryer first (since the system will be open and exposed when the compressor is replaced). www.acpartsnow.com (aka brightauto) has them pretty cheap. That's where I got mine and haven't had any problems with it.
But anyways, take a look and see if the clutch is engaging and disengaging. It's easy to check and doesn't cost you any money.
Jul 14, 2008, 01:07 PM
#5
thanks for the input lumpy...
when the car is first turned on... it functions properly...
turning the a/c system on and off made the clutch engage and disengage...
once the car is up to temp... the clutch disengages and never tries to re-engage...
any more ideas would be appreciated.
regards
flip
when the car is first turned on... it functions properly...
turning the a/c system on and off made the clutch engage and disengage...
once the car is up to temp... the clutch disengages and never tries to re-engage...
any more ideas would be appreciated.
regards
flip
Jul 14, 2008, 01:12 PM
#6
yes... i have a cabin filter...
cabin filter smelled like mildew and my squash airfreshener... was pretty dirty...
i plan on picking up a new one today to alleviate that issue.
is there any way to verify if the evaporator is clogged? any way to unclog it?
thanks for the input!
regards
flip
Jul 14, 2008, 01:55 PM
#7
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Most cars have a temp sensor in the cooling system (for just a/c) that if temps get to high, the a/c will turn off to help prevent over heating.
Also do your fans run when the a/c is turned on?
A/C is a very simple system to understand. But we need more info.
Also do your fans run when the a/c is turned on?
A/C is a very simple system to understand. But we need more info.
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Jul 14, 2008, 02:02 PM
#9
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When the a/c turns off after xxx time, have you checked to see if there is 12 to 14 volts going to the clutch.... when your not driving 65
Jul 14, 2008, 04:59 PM
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If you have no voltage- that means something is telling the a/c not to cycle on/off. Possible high/low pressure switch
If you have battery voltage there- chances are you compressor coil is weak, or the air gap between the clutch and coil is too much. When the a/c is turned on but not functioning- check for battery voltage at the compressor. If you have it- very carefully (I can't stress this enough) poke the front of the compressor with a piece of wood and see if the compressor comes to life. Again- be careful doing this
If you have battery voltage there- chances are you compressor coil is weak, or the air gap between the clutch and coil is too much. When the a/c is turned on but not functioning- check for battery voltage at the compressor. If you have it- very carefully (I can't stress this enough) poke the front of the compressor with a piece of wood and see if the compressor comes to life. Again- be careful doing this
Jul 14, 2008, 05:17 PM
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3 other components that will shut down the A/C are the Air Thermo Sensor inside the evaporator housing, Refrigerant Temp Sensor in the compressor, and the Dual Pressure switch. If the evaporator gets too cold, the A/C ecu deems that it is freezing up and sends a signal to the ECU to turn off the A/C relay. If you let the car sit for 1/2 hour will it work again? The Refrigerant Temp Sensor on the compressor will shut down the A/C clutch coil if there is a restriction that causes the refrigerant to get too hot (302°F)