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Over charge

bigmillz on Fri May 23, 2008 1:08 PM User is offlineView users profile

Year: 1998
Make: Honda
Model: CRV
Engine Size: 2.0l
Refrigerant Type: r134a
Country of Origin: United States

While I was out of town my wifes 98 crv's A/C compressor clutch started to click on and off when at idle. If she pushed on the gas just a little it would stop. It was also idling at 500 or sometimes below. I told her I would check the idle when I got home.

Well my genius brother came over and told her the freon was low. Then he put 134a in the system without a gauge. She drove it 2 or 3 times and when I got home it was blowing warm air and was way overcharged when I put my gage on it. I evacuated it until it was right. The air is cold again and the clutch is not clicking on and off anymore but there is a 5 second hissing sound behind the glovebox. It happens often while running the A/C and when I turn it off it hisses for about 10 seconds.

My question is: is this a problem and if so what can I do to fix it.

I have a lot of knowlege on repairing cars but never took the time to learn A/Cs. Any help would be greatly appreciated do to the fact that it seems like you have to be wealthy to get an A/C worked on. They charge a ton for anything dealing with Airconditioning.

mk378 on Fri May 23, 2008 1:29 PM User is offline

That sound is usually normal, it's refrigerant flowing thru the expansion valve.

The only way to be sure you're properly charged is to remove it all and then put in the right amount by weight.

As you probably know but your brother doesn't, when the engine is idling at too low a rpm the engine computer will drop out the compressor to keep it from stalling. That is why it was clicking on and off in the first place. It's not a problem with the A/C.

bearing01 on Fri May 23, 2008 3:28 PM User is offline

You have an expansion valve system. I don't know the details of your compressor but I would think it is a variable displacement type, therefore it shouldn't normally cycle on/off, except for when ^^he said. ACkits is showing you have a binary pressure switch. I'd make a guess that that switch probably disables the compressor if you lost all refrigerant or if high side pressure rockets because of overcharge or a dead condenser/rad fan or something.

Do you have a real set of (AC manifold) gauges or just a cheapo gauge that came with a can of refrigerant?

You should be able to tell (ballpark) if you're overcharged by measuring the amount of subcooling out of the condenser. You would need a real gauge set to measure your high side pressure for that.

Edited: Fri May 23, 2008 at 3:30 PM by bearing01

mk378 on Fri May 23, 2008 3:43 PM User is offline

I think it's going to be a fixed-displacement expansion valve system. On these, the compressor will not cycle rapidly because it's low on refrigerant. It will either come on and stay on, or not start at all depending on whether there is enough left to trip the pressure switch. The OP's brother should stick to American cars.

bigmillz on Fri May 23, 2008 5:25 PM User is offlineView users profile

bigmillz on Fri May 23, 2008 5:41 PM User is offlineView users profile

I took it to an a/c man and he evacuated the system and then charged it and said that the speedvalve or switch on the compressor is killing the clutch. He said I need a new compressor, drier, evaporator and expantion valve. He also said I need to flush the system because there may be metal inside. Is this for real or is he trying to take me for a bunch of money. Can I do all this my self since they took all the refrigerant out. The car cooled just fine before my brother put that can of coolant in it. The only problem was the clutch kicking on and off. This is not cool I live in south Texas and its only getting hotter.

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