A/C compressor failure
 

Hi! I've been having trouble with my 1999 civic's A/C lately and I was hoping someone could help me with it.

Symptoms:
High preassure too high on minimun (200 psi)
High preassure rises up to 400 psi when accelerating
High preassure gauge vibrates
Compressor sounds loudly
Activates and deactivates repeatedly
Takes a lot of power out of the car
Doesn't cool air as it should

I already have:
Changed dryer and expansion valve (2 months ago)
Replaced condenser fan motor
Cleaned the entire system
Cleaned condenser and evaporator

Questions:
Is it the compressor that's failing or could it be something else?
If I replace the compressor, should I also change the valve and dryer, even if they're only a couple months old?
What else should I do to replace the compressor?

Re: A/C compressor failure
 

System is seriously Overcharged or there is a blockage?

What is the low side pressure doing at idle
and what is the low side pressure doing when the RPM is raised and high side goes off the chart?

Re: A/C compressor failure
 

System is not overcharged. It is actually undercharged, only has 400 g of R-134a because i didn't want to charge it completely. I don't know if is is blocked somewhere, but I changed expansion valve and dryer checking if they were blocked and it didn't solve the problem.

At idle, the low pressure side is at 40 psi, and when I rev up the engine it goes down slightly, around 20 psi. It used to go lower, almost to 0, before I changed the valve and dryer.

Re: A/C compressor failure
 

Too much oil in the system can mimic an overcharge condition, as it takes up valuable space inside the system and can't be compressed in liquid form.

Condenser fan is operating when the AC is running?

You say you cleaned the condenser and other parts.....did you check for good flow volume through the condenser pipes?

Has it ever had a compressor failure?
Does this compressor sound noisy?

If the system is truly undercharged then there almost has to be a blockage somewhere after the high side service port.
(A failing compressor will often send debris into the condenser, which becomes a restriction. If your high side service valve is between the compressor and condenser, you would be able to see extreme pressure on the gauge.)

Feel the system while it is running, figure out where the high side of the system makes a big temperature change.
If there is a restriction, it should also act like a second orifice or expansion valve and should cause a temperature change.

Re: A/C compressor failure
 

Well, I hadn't paid much attention to the condenser fan since it had been replaced recently. Turns out that now it isn't running, and I'm guessing it never worked very well since it is not an original part, and that's why it didn't solve my problem. Now that it does't work it got way worse. So can the failure I describe be caused by the malfunctioning of the fan? I took it to a A/C shop, they threw water through the compressor and the pressures instatly dropped to normal levels, as if the heat exchange couldn't be done on its own with regular air, so I'm guessing condenser fan is a good guess.

On the other hand, I don't know if there's excess of oil. Is there a way to measure that without bringing down the compressor?

About an obstuction, I can't check what you say about the change in temperature since I can't turn the A/C now.

Re: A/C compressor failure
 

Absolutely, that's why it was up near the top of my guesses LOL.

Fix that and recharge with the correct amount of freon (if necessary) and see if it cools correctly again.

If it cools ok after that then I wouldn't worry about the oil.

Re: A/C compressor failure
 

As you said, seems like the fan was the problem. I replaced it and works great, considering it has less gas than it should, although I didn't get the chance to check it with the manometers. I'll do that and if everything goes well, I'll add the neccesary amount of gas.

Thanks a lot!