I'm an A/C n00b

[Wrider]

Cross-posting this from CRN.
So I work on bikes. Bikes don't have A/C yet (yes I'm eyeing you Goldwing and BMW).

Long story short, my sister has a 2002 Impreza 2.5 TS with A/C that was not blowing cold. It blew weakly last summer, and this summer is completely useless. I bought one of the Wal-Mart cans of refrigerant and drained the system (it still had full pressure btw), then put in the can until the recommended pressure. It's still not blowing cold (even weakly).

My train of though says that this means the compressor is bad. It does engage, it's not seized or anything, but since the refrigerant is brand new, I'm guessing there's something else in there that's bad.

What say you?

Oh and if the compressor is bad, does anyone have a compressor off of an EJ25 they're wanting to get rid of?

[Cornfed]

A/C system works just like the heating system.
Antifreeze is to freon.
Water pump is to compressor.
Radiator it so condenser.
Heater Core is to evaporator core.


The compressor could be engaging, but not actually moving the freon due to an internal failure. I.E. water pump is turning but the propeller is broken/eroded and not moving antifreeze.

Hope that helps.

[Wrider]

Makes perfect sense. Will be looking for a new compressor then.

Anyone have an EJ25 A/C compressor for sale? Anyone?

[mauser72]

can you watch the compressor clutch turn on and off? If the comp is cycling its prob. ok my guesse is it just needs to be charged properly those refrigerant in a can is not a good way to charge the system it needs to be put under a vacuum for at least an hour to pull out any moisture and to find any potential leaks in the system and then filled to the factory specs take it to a shop with the proper equipment before doing anything else.

[madvlad]

Check for a leak or also maybe its the temperature blend motor.

[Wrider]

FWIW the blend motor definitely works. If you turn it to hot it blows you right out of the car at these temps.
No leaks. Like I said it had 100% pressure before I started on this journey.

I might just do the shop thing. Anyone know how much that usually costs?

[mauser72]

Should cost about an hour of labor and whatever 134a costs these days. Once you get the ac squared away tell your sister to turn on her ac a couple of times during winter months, the compressor seal needs to stay lubricated in order to keep a good seal otherwise it will slowly leak out and will need to be charged again in the summer.

[matt2778]

What did you charge it to? When working with a/c there really isn't anything like 100%. On a car it needs to be filled with the correct around of freon measure in pounds. If you are undercharged it wont work if you are overcharged it won't work. If a compressor is bad it won't work. A compressor clutch/pulley may be bad. You may have a blockage causing it not to work. An expansion valve could be stuck. A pressure switch could be bad or wiring to any of the switches,connectors or sensor could be bad.

[Wrider]

On the back of the can it said in 85-90 degree ambient temp to charge it to 45-50 psi. I was right at 47 psi so I'm pretty sure it was right unless the gauge was off.

I'm thinking I'll just help her out with the service bill on it because I was reading how many ounces the AC was supposed to take (15-19), and with a 22 oz can I was able to charge it to the correct pressure 3 times with some left over. Blockage seems to be the biggest candidate here.

[matt2778]

Did you charge from the low side or high side? Low side pressure should be about ambient temp. Those charge in a can really don't work that well.

[Cornfed]

Makes perfect sense. Will be looking for a new compressor then.

Anyone have an EJ25 A/C compressor for sale? Anyone?

Let me clarify, I only said that to give you a general understanding of how the system works, not to tell you to replace the compressor. I work at Brakes Plus and we charge $75 labor + $25 a pound to diagnose and recharge the system. You may or may not be able to find the A/C service cheaper, however Im confident whatever you pay a shop it will be cheaper than hanging parts it doesnt need.

[NUTZ]

Is the compressor constantly cycling on and off?

[Wrider]

Did you charge from the low side or high side? Low side pressure should be about ambient temp. Those charge in a can really don't work that well.

Low side. Tried from the high side until I figured out the connector wouldn't work, then traced it and found the high side. Guess the H and L caps should have given it away, but I can be a bit thick sometimes... lol

Let me clarify, I only said that to give you a general understanding of how the system works, not to tell you to replace the compressor. I work at Brakes Plus and we charge $75 labor + $25 a pound to diagnose and recharge the system. You may or may not be able to find the A/C service cheaper, however Im confident whatever you pay a shop it will be cheaper than hanging parts it doesnt need.

Probably, that's seeming like what it's going to come down to, plus you guys can pull a vacuum on it, which I don't have the tools to do.

Is the compressor constantly cycling on and off?

No, stays on while it's on, then turns off while it's off.

[cbrjohnny]

the schrader valves are a common place for leaks. the stuff you get in a can sucks. you need to have the system evcacuated and charged then test for leaks with a leak detecter. this is the only way to start the diagnostic process on ac. dont waist money on "ac pro" b.s.!

[eg bter]

Good write-up:

1. Introduction
   
   
   
   • When a air-conditioning system (A/C) is being diagnosed, it must have Freon in the system. If the system has sprung a leak somewhere and the Freon is gone, it is no longer an active system that can be checked. A leak would have to be repaired before further diagnosis can continue. Freon can't be released into the atmosphere and must be reclaimed in a machine and reused. There is a major fine for releasing it into the air. For the purpose of this procedure, a circuit tester and a set of air-conditioning gauges will be needed.
     
     
   
   About the A/C System
   
   
   
   • There are several parts to an air-conditioning system, making it somewhat complex. The main parts of the air conditioning system include:
     Compressor: This raises the pressure and temperature of the Freon.
     Dryer: This removes sediment and captures and retains moisture.
     Condenser: This acts like a radiator and releases the heat to the atmosphere.
     Accumulator: This does the same as the dryer, except it's used to also capture liquid Freon so it doesn't reach the compressor. depending on the year, the Honda Civic may have a dryer or an accumulator, but never both.
     Expansion valve: This takes high-pressure Freon and turns it into a low-pressure, low-temperature spray that moves into the evaporator inside the cabin and withdraws the heat.
     
     
   
   Diagnosis
   
   
   
   • Because there are so many parts involved, the first thing is to test the system from inside the car and see exactly what is happening so there's an appropriate place to start looking for a problem.
     If the inside fan doesn't come on with the A/C, lift the hood with the engine running and the A/C on. Look to see if the compressor is turning and feel the largest A/C hose to see if it's cold. If it is and the compressor is on, the system is all right and the problem is in the blower motor. If the compressor isn't on, the problem could be a matter of power to the system, a bad control head on the dash or no Freon. Start by checking the fuses in the fuse and relay panel under the hood on the driver's side. Replace the fuses as necessary.
     If fuses were not the problem, hook up the A/C gauges to the system with the red line going to the high side (the small line) and the blue line going to the opposite, large-diameter, low-pressure side. The gauge should show close to 80 lbs. on the blue low side and 140 on the red high side, depending on outside temperature. This is with the compressor off. It takes this much pressure to turn on the low side switch and allow the compressor to work. At this point, the inside fan is a separate issue if the compressor was not on and will be dealt with next.
     If the pressure on the gauges was less than prescribed, there is a leak in the system. It must be repaired to continue under the hood. The fan is under the passenger side dash close to the glove compartment. Use the circuit tester and check for power at the 2-wire connector on the blower motor (the key and fan must be on). If there is no power to the fan, the fan is bad. If there is no power, move to the blower motor resistor right next to the blower motor. It's usually to the left and slightly to the rear, and is used to control the speeds of the fan. Check to see if there is power to the resistor. If there is power, the blower motor resistor is the problem and should be replaced. This is a very common problem and inexpensive. It can be done without going to a shop. If there is no power, it's a bad control head on the dash.
     
     
   
   
   
   • If the A/C system has too little or too much Freon, the high or low side valve will shut down the system to prevent damage to the compressor. If this is the case, a very expensive reclaimer must be used to adjust the Freon level. An ASE technician certification and a MACs card is needed to own one, so it must go to a shop for further diagnosis. However, if there is Freon in the system, the following is a good diagnosis of problems that can be identified.
     
     
   • 1. If there is a clattering noise under the hood with the A/C running, the compressor is going bad and will soon need replacing.
     2. If there is a metal-to-metal sound like a grinding when the compressor comes on, the clutch is bad on the compressor and can be replaced separately.
     3. If the system isn't cold enough, feel the large line under the hood for the A/C. If it's warm, feel the small line but be careful; if the compressor is working, the small line should be hot. If not, the compressor is going bad. If the large line is cool but not cold and the small line is hot, the system just needs a recharge.
     4. If the compressor keeps cycling on and off frequently, the system is low on Freon and only needs a charge.
     5. If both lines are warm or hot to the touch, the expansion valve is malfunctioning and must go to the shop.
     6. If the A/C is cold when the car is in motion and warms up when stopped, the condenser fan under the hood isn't working.
     
     

[madvlad]

I found a TSB on AllData that relates to this issue. I'll try and e-mail it to you. PM me your email

[Ricky]

Does it have one of those little viewer window things? Usually you can see the refrigerant moving through the pipes when the compressor is engaged, compared to when it's not running. Just a thought.

[highpsi03]

Does it have one of those little viewer window things? Usually you can see the refrigerant moving through the pipes when the compressor is engaged, compared to when it's not running. Just a thought.

I haven't seen that used as a method since R12....

If you want to see if the compressor is working grab both lines, high and low. You'll notice one is hot as shit and one will be ice cold and sweating..

[Wrider]

You are just digging up all kinds of dead threads today aren't ya?
Turned out to be a bad condenser.
Fixed in late July.

[jbnwc]

Just curious... How much did it end up costing to fix?

[Wrider]

I had no idea what I was doing so we took it into a shop we like. I think the total price ended up being just under 300 including replacing the compressor.

[jbnwc]

I had no idea what I was doing so we took it into a shop we like. I think the total price ended up being just under 300 including replacing the compressor.

compressor or condenser? I was quoted a price for just the compressor(no labor) at $675.

[Wrider]

I'm honestly not sure. Sister's car. I'll ask later.

[highpsi03]

You are just digging up all kinds of dead threads today aren't ya?
.

Who cares really? The information i have given could help someone in a future search.