A/C help

[oh_SHO]

First of all. I don't know much about the a/c system. I'd like to see if I could get it to work in my '95. The car sat for about 10 years but the a/c worked when it was parked. I had the water pump and timing belt replaced (ouch!) but told them to forgo the a/c repair since I was out of money. I figured the system was low of freon so i went and added some. Now the gauge reads on the high end for the ambient temp but the compressor hasn't kicked on.

Please point me in the right direction! Thanks!

 

[jman1200]

What were the symptoms when it died? Many things can go wrong, that could help troubleshoot.
When you recharged it, was the compressor running? If not, how did you recharge it?
If it ran, you might have over charged it and now the high pressure switch is triggered. With the engine and AC running, slowly bleed some refrigerant out until you see the compressor kick in.

 

[Tim Brand]

Just to add you could have a blown fuse the compressor or the clutch itself may be frozen up since it has been sitting for 10 years. Or like jman said you may have overcharged it, or not at all not sure of they have a low limit switch but if it does it won't let the compressor come on either

 

[luigisho]

Can you afford to have an a/c pro give you a diagnostic and estimate on it? If you are not familiar with a/c systems you could spend alot of time and money throwing parts at it. At that point you can determine if you want to do it yourself or pay them to get it up and running

If you don't have the extra shekels then I agree with bleeding it off to start.

 

[rubydist]

No, this is wrong. DO NOT bleed off anything.

There is no way it could be overcharged to the point where the high pressure switch is always tripped. That is over 200 psi and the canisters do not have that kind of pressure in them.

Start by removing the connector on the low pressure switch and jumper that connector. Does that make the compressor kick on?

If not, remove the connector on the compressor and put a 12V light across the two pins of the connector. Does the light come on when the a/c should be on?

If not, then there is some wiring issue to chase down.

If it does light the light, then tap on the compressor clutch to see if that will engage it. These clutches are known to wear such that a shim removal is required. I have seen these go from working fine one day to not working at all the next, so the clutch is the most likely culprit.

 

[oh_SHO]

Thanks rubydist. I will start there. I talked it over with a co-worker who's dad did HVAC for years and he basically recommended the same thing.

 

[jman1200]

The DIY way to recharge a car's AC is to hook up your canister to your low pressure line (compressor's intake). Canisters do not have 200 psi in them, but the compressor will suck and compress in as much gas as you feed into that line and go past 200 psi.
If you keep putting gas in you can get to a point where the high pressure switch WILL kick in. I know because I have done it, I spent a whole Summer sweating in my Sienna thinking the AC was broken just to realize, 12 months later, that I've overcharged it. Bled some out and it worked again like new.

 

[Airborne]

Get some guages and get back to us. Even if you jumper the compressor, that only tells you info about the compressor. Guages will tell you what is going on.

 

[zak]

On my 95 MTX there was a corroded pin in the harness at a connector half way in between the CCRM (relay module bolted to top of radiator support) and the plug on the side of the compressor near the pulley. Cleaned both sides of the connector (electrical contact cleaner for the female side, fine black sand paper on the pin) and the compressor worked fine for another 15 years.

Another item that takes these AC systems out is the clearance in the clutch which opens up after time, especially given that the clutch is opening and closing on a relatively high winding engine (don't know the spec off hand, but you are measuring, with the car off, the gap between the metal plate on the compressor clutch and the black rubber puck underneath. If you have small hands and can get the AC clutch plate removal tool from Autozone you can pull the bolt and the plate off, remove one of the two washers and close the gap down.

 

[rubydist]

The DIY way to recharge a car's AC is to hook up your canister to your low pressure line (compressor's intake). Canisters do not have 200 psi in them, but the compressor will suck and compress in as much gas as you feed into that line and go past 200 psi.
If you keep putting gas in you can get to a point where the high pressure switch WILL kick in. I know because I have done it, I spent a whole Summer sweating in my Sienna thinking the AC was broken just to realize, 12 months later, that I've overcharged it. Bled some out and it worked again like new.

The above is true, but the op says in the first post that the compressor will not kick on, therefore there is no way the compressor will build up the pressure. That is why it is impossible for it to be overcharged in this case. Please note I did not say it is impossible ever to overcharge them with the canister, I was responding to the specific symptoms he stated, for which my response was correct.

 

[jman1200]

On my first post I asked the OP how did he recharge the system. So far he has ignored the question.
I don't care if I am right or wrong, apparently you do. You said my comment was wrong without having all the pieces of the puzzle. Again, I do not care, I give advise, that is what forums are for, the OP can either listen or not. I never said you comment was wrong, it is the right thing to do once you know it is not overcharged.

I'm not here to pick fights, therefore this will be my last contribution to this thread. Moderators should encourage participation, not shut it down.

 

[luigisho]

It's ok to disagree as long as it's done agreeably. It's the internet and communication gets clumsy interpreting text. believe me, things can get ugly online and this board is really good by comparison.

 

[rubydist]

What I care about is giving useful direction to a person asking questions. In this thread, the op was given conflicting advice regarding whether the system might need to have pressure removed. It is literally impossible for both "bleed off some pressure" and "do not bleed off any pressure" to be correct and helpful direction to the op. Therefore, in order to be of help to the op, it is necessary to point out which of those directions is appropriate, given the description provided to us. I don't care a whit who made the proper suggestion, but I care a great deal that the op is given direction that does not waste his/her time and/or money.

 

[oh_SHO]

I will respond to questions that weren't already answered in previous posts. So if I'm ignoring a question them, most likely, it was already answered. I should be able to read between the lines and apply the right logic to my situation. I appreciate the help either way.

So here is my update. I was able to bypass the low pressure switch which the clutch did engage and started the compressor. I was able to add the rest of the re-fill can I had (only a couple ounces) but the system wasn't building pressure. When I pulled the jumper and the compressor kicked off the pressure on the low side went to 60 psi (I think. I don't remember the scale of the gauge). I have a feeling there still just isn't enough pressure to actually cool anything but I found someone proper set of gauges. He's willing to hook them up so we can see whats going on with both sides of the system. I will post back with what we find. Probably another couple of days.

 

[luigisho]

Post back. Curious to see what the issue is. At this age anything could be wrong with the thing. I spent a ton of money redoing the entire ac system on a car I got rid of the next year. Cost me a pretty penny but summers are hot and humid around here and gotta have it

 

[rubydist]

sounds to me like its still low. every time I have started from a very low system, I have had to jumper the low side switch to get the compressor to run in order to pull the refrigerant into the system. if its that low, it will take 2 cans.

 

[oh_SHO]

We just dumped two cans in and i have cold air. I think it's still a bit low but I don't want to put in anymore until I know if it's gonna hold for 2 hours or 2 months. I think it's supposed to hold 2 lbs so i probably have put in around 26 ounces ( 2x12 onces cans + one partial).

Engine was real hot but once it cools down I'll remove the bypass and plug the low pressure switch in. I didn't totally understand the pressures but it's holding right around 30 psi on the low side with the compressor running. Just in time as it's supposed to be in the 90s by the weekend. Fingers crossed it holds.

 

[oh_SHO]

Oh. Has anyone used stop leak products in the a/c system? Or is it like fix a flat and only do it on a car you'll never see again?

 

[luigisho]

I wouldn't do it but I wouldn't use it in the coolant system either. Are you planning on using this car over the medium term? If so I would locate the leak(s) and decide from there.

 

[oh_SHO]

I don't have a set plan for the car. I'd probably sell if someone walked up and offered me something reasonable. But I'll probably run it for the next year at least so I'd rather not do harm to it. As of now it's probably just seals. I don't want to get into condensers and the like cuz i plugged it up trying to band-aid it.