I was driving up to Dallas with some friends yesterday. While I was passing a truck I shifted late, went into redline, about 7000 rpm and the redline starts at 6500 rpm. There was a small pop/jolt and shortly after the ac stopped blowing cold air. Stopped to check on it. Ac belt is fine. Ac compressor doesn't kick on when the ac is turned on. Aux fans don't kick on. The ac clutch turns freely when the car is stopped. All the fuses look fine. I can't test the relay until I get home. What do you guys think is wrong?
ac is dead. Ideas?
- Thread starter alphatarget1
- Start date
By "aux" fans your referring to the main cooling fans right?, these should come on every time the AC is on to pull air through the condenser coils so my guess is it's prolly a relay. BTW a lot of cars will disengage the compressor with a WOT (wide open throttle) condition so as to have more power available for passing..
Bartman39
Elite Member | For Sale/Trade
- Jul 4, 2000
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LOL...! I remember when they started doing this way back when on Suzuki cars when I worked at a Nissan dealer... We thought it was to allow the rubberband to wind up better...:thumbsup:
I agree if the aux fans dont work also then there is a power problem which points to the AC relay which I think also controls the aux fan relay on most cars...? What car is this anyhow...?
Replaced A/C relay and the thing didn't work. I'm leaning towards a dead compressor. Is the cooling fans for the condenser temperature dependent? Right now when I turn on the A/C, the compressor clutch doesn't engage. I'll check the clutch operation tomorrow, factory service manuals are handy lol.
CrackRabbit
Lifer
- Mar 30, 2001
- 16,642
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I'm not sure if newer cars have them but you might look for a refrigerant pressure switch.
I had one go bad in an old truck of mine. Took me forever to figure out that was the problem.
I had one go bad in an old truck of mine. Took me forever to figure out that was the problem.
Bartman39
Elite Member | For Sale/Trade
- Jul 4, 2000
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Normaly you can hookup a set of AC gauges on the system and should see base pressure around 100psi or a bit more... Crackrabbit has a good thought the pressure switch might have stuck...?
Still need to know what car we are dealing with...? Kinda makes a difference...
Take the wiring harness out of your condenser bottle and short the 2 leads with piece of wire to see if it's a pressure, or pressure sensor problem. The compressor should engage when you do this.
On my '94 Escort the AC was almost like an extra brake, I had to click it off before even attempting an on ramp..
It's a '05 Subaru Legacy. Service manual says to provide power to the magnetic clutch to see if it engages. If it doesn't, replace the compressor. I'll try to see if the magnetic clutch engages before looking at the switch.
Checked AC compressor clutch. Clutch works fine. No voltage to the compressor. I suspected it was low on refrigerant so I took it to a shop. They checked it and said there is a hole in the condenser. I bought a new condenser and I'll put it in and have the shop evacuate/recharge the system. Way better than replacing a compressor!
It makes sense now. When I was passing the truck a rock hit the condenser and knocked a hole in it. The "pop" was from the compressor disengaging as it should. Replacing it shouldn't be horribly hard...
One more question for you guys- as far as the compressor oil goes, do I actually have to physically remove the compressor to get the old oil out and new oil back in? I'd rather now as this means I have to remove the compressor and replace 2 more o-rings.
Meghan54
Lifer
- Oct 18, 2009
- 11,684
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1. Replace the condenser and since you've opened the system, you need to replace the receiver/drier, too.
2. Have system evacuated out.....vacuumed out. (Some will recommend this prior to disassembly of the system, but since you've got a hole in your condenser, that point is moot as the system will just let the vacuum suck air through the hole.)
3. Recharge with Freon.
I try not to use my AC except when it's really brutal outside, for some reason or other AC systems don't seem to last as a car gets older. If I'm cruising on the highway I just roll down the windows, my last car I bought new (94 Escort) I got the AC to last to 185K by using it sparingly..
using it sparingly may actually prematurely kill it. using it regularly may put extra wear on the compressor, but will keep seals and o-rings in better condition and likely extend the life of the system
True, but I always run it for 10 minutes or so every week, year round. Also most cars will engage the compressor in defrost mode anyway..
That is really only needed if it is necessary to do so in order to comply with warranty terms of a new compressor. You are not going to have the system open long enough to have the drier become saturated with moisture and if you are going to have it open for a while plugging the ends of the drier does the job.
The reason most people should replace them, and why shops do, is they simply are not going to pull a vacuum long enough. Fifteen minutes is not sufficient. If you have access to a vacuum pump then simply pull the vacuum for 6-8 hours or overnight and there is simply no way there is going to be any moisture trapped in the drier.
Not likely. Air is not going to get into a small hole that easily and then contaminate the whole system. It just isn't. Especially if he has been driving it regularly which means everything gets hot.
Doesn't matter anyway. If you understand anything about vacuum you would realize you could leave the drier open to the air for months and still pull all the water out of it by vacuuming it for a long time. At 29 inches of vacuum water boils at about 45F. So unless you are doing this in freezing temperatures you are going to get all the water out if you leave the vacuum in place long enough. The pump constantly vents to the atmosphere so you will remove all the water.
EDIT....I'm to tired and have a headache so I am not going to rewrite the above, it was not intended to sound insulting.
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