Desperatly seeking A/C help...

[areonic1]

Ive been to this forum alot, but never reg/posted so i wasnt an annoyance, but things just keep getting worse in my situation. Alright, It might be a little lengthy, but I want to give as much info as possible to prevent back and forth, and sorry if it seems Ive bounced around...

1993 Ford Explorer, Limited

I bought the car about a week ago, and the owner said the only thing wrong with the AC system, is the clutch wont engage and it needs freon. So read up a lil, found out how to test the clutch bypassing everything. Clutch worked, and it had 0 freon in it, so i thought the sensor wouldnt let it kick in with no freon. Filled it up with freon, clutch engaged, seemed to be getting better, turned car off, heard leek, was coming from the pully shaft on compressor.

Bought new compressor, bought more freon, filled it up again, started blowing ice cold, all of a sudden, i burst of sound, like pressure relief or a BOV from a turbo...now its empty on freon again. Figured I put too much, tried again, filled it up just enough to where the clutch would stay engaged, instead of going in and out, time it stayed engaged, i stopped. Seemed to hold, put it in gear to test drive, everything blew out again.

Now I take it to a repair shop, they say the dryer thing, and orface tube needs to be changed, I bought the parts, payed them to put it in, (this is all coming from what they say) The original orface tube was put in wrong, they had to put oil in and what not to get it out. Put new stuff on, ac blew cold for a few mins, they drove it down the road, warmed up and no more cold air. THEY CLAIM ITS A LEAK. I asked for proof, How do you know its a leak etc....They said the system was at 35psi, and now its at 20..an hour goes by before I get there, so if theres a leak, it would be even lower. I asked to put a meter on it, to see if it went lower, they refused and argued its a leak. I dont believe it at all. They even went over it with a sniffer in front of me and it never beeped.

I take it to a different shop on the way home, really upset i just blew money and in a worse situation. He checked the pressure, its 90+ when the ac is turned OFF, but as soon as the clutch engages, the pressure drops down to 20 for some reason. He said theres no leak, since the pressure was fine when its not on. Something about its pulling a vacuum on the low side or something. That the first group might have put something on wrong, or what not.

Now later in the day, someone told me, that something similar happened to them once, and its cause garbage was in the lines or something and they blew it out with an air compressor and it started working fine. That a clog could cause my problem.

My problem is, I dont know much about ACs, but I can do alot of other stuff with working on cars. I really cant afford to drop alot more money on something I can do, if i knew what to do. Like today, I could of saved $200, just by standing in front of my car for 8 hours, swapped a part that took 30mins and screwed it up. I would really appreciate ANY HELP at all on this, cause Ive already gone through 600bux and I cant afford it to keep going. AC isnt a big deal, until i try to drive with my 4 and 1 year old in the car.

Thank you in advance!!

EDIT!! Its an Accumulator and orface tube that got swapped, not a dryer.

 

[Iron Weasel]

Easy "shade tree" way to check for a leak is to look for an oily residue and debris collected in a certain area of the A/C components. A more precise but more expensive way to find the location is to put some dye in it that glows under UV light. Any reputable shop will do this for you and usually charge a diagnostic fee which is a lot better than throwing parts at it. If you would rather do it yourself, you can usually pick up a leak detection kit that includes the dye, UV light, and goggles for $50 - $100+ depending on where you buy it.

If it's blowing R12 (or R134a if it's been converted) out and you can hear it, you need to figure out where it's blowing out from, then you'll have a better idea of why.

Here's the pressure / temp chart from my 94 so you'll have a better idea of what the pressure readings should be.

If it was 65° outside when you had it checked, then 90 PSI on the high side is fine, otherwise you're still running low on refrigerant which is to be expected if you have a leak somewhere. Also, here are the component test charts...sorry for the size but they're a little hard to read at smaller sizes. :

Static pressure won't really tell you anything, you need some manifold gauges hooked up while the vehicle is running then you'll be able to look at the pressure / temp chart and get a good idea of what the pressures should be. From there, look at the two charts above and match the pressures / symptoms up.

 

[areonic1]

But the second guy doesnt think there is a leak, it was holding the same pressure an hour or 2 later. Whats happening is, when the ac clutch engages, the pressure drops, then goes back up when it disengages.

 

[kelvin37]

there is a clog in a condenser. i had the same problem on my 91. i replaced an orfice tube, compressor, and a condenser, with 134 a synthetic. i constantly blow 38 degrees down the road and 42 at idle. if your dont want to replace your condenser you can take both hoses off and run brake cleaner from the low side through the high side, and blow it out with an air compressor. just make sure you have a filter on your air hose so you dont get water in there.

 

[areonic1]

Alright, So i started on it today, took the orface tube out and a bunch of oil and junk came out with it. Sprayed brake cleaner in the evap core, and air compressed it to get the rest of the milky oil gunk out. Swapped compressor for another new one. Hooked it back up, put freon in it, AC temp started to drop, got really cold, was at 45psi with the AC on. Closed hood and everything, put it in reverse so i can test drive it, soon as i put it in reverse, it blows all the freon out...think theres a relief valve. Now, it blows 80f out the vents, put more freon in it, till about 45psi, sat there for a min, it blows out. Now its just sitting between 80-85 out the vents.

Not sure if it matters, when the AC is off, its about 90-100psi , but when it kicks in, thats when it drops to the 45ish.

Any suggestions?

 

[Iron Weasel]

So if it's just sitting there at idle speeds, everything is cool (pun intended)?

What happens when you rev the engine without putting it in gear?
What about a different gear (1st or Drive depending on transmission)?
Does it still blow refrigerant out everywhere?

There's a pressure sensor that sits on top of the compressor and interrupts power to the compressor if the high side pressure is too high, but that doesn't actually vent refrigerant. There's also a relief valve on the high side line near the power steering pump, it should have a 2-wire plug going to it...looks like a black oval.

Clutch Cycling switch: http://img202.imageshack.us/img202/8412/dscn0789h.jpg
Pressure cut out switch: http://img713.imageshack.us/img713/9379/dscn0790.jpg

The text doesn't stand out real well on the picture of the cut out switch, but it's right next to the switch. At any rate, that's why I suggested adding some dye to the system and then buying / borrowing a UV light and goggles so that you can see where the refrigerant is blowing out from. It could be coming out from the pressure cutout switch, the high side service port, etc...you need to figure out "where" then you might have a better idea of "why".

 

[areonic1]

Its coming out from under the engine, kinda close to the firewall....if that helps any

 

[areonic1]

Ok just went back out, I think I really know where its coming from....The block thing you bolt into the back of the compressor, theres 2 lil valve looking things on there, I think its coming from there, the reason why is...I just pt the compressor on, so it should be dry with nothing on it, I wiped around that spot and there was oil and residue there, along with all over the stuff surrounding it. So I THINK thats where its blowing out..

I have not done the condensor thing yet btw, cause I cant afford to keep buying parts unless I know its that.

 

[Iron Weasel]

That little block you're talking about only fits on one way, but it can be kinda hard to actually get in position.

Make sure you only have one O-ring per hole back there. Also, the bolt only gets something like 15ft-lbs of torque, so make sure you aren't going all ape-**** on it.

 

[areonic1]

Theres one more thing, might be dumb...but when i got the compressor, one side had a lil rubber thing in the hole and it had a stim on it, was i suppose to leave that on or take it off before attaching the block? Cause I took it out, it looked like a block or something

 

[areonic1]

That block that bolts into the back of the compressor, has the one bolt in the middle that holds the block on. Then theres 2 other things on it, one right beside it, and one on the bottom side of the block, I think its blowing out of the port beside the bolt that holds the block on

 

[areonic1]

OK took the block off, there is nothing else in there, except the 1 oring on each side of the compressor

 

[Iron Weasel]

The "port" you're talking about is a round plug looking object with a hex on one end that you can put a socket / wrench on, right?

If so, the one on the bottom is a big Schrader valve, while the one on the back that is horizontal is the High Pressure Safety Valve. If it's blowing out of the safety valve, then you could very well have a clog on the high side line somewhere.

 

[areonic1]

Alright I got an update and I hope this helps....I filled it back up with freon, until it got about 38psi. Sat there with the gauge on it for about 5mins, not putting freon in it, it slowly, really slowly climbed to almost 45psi itself. Alright, now I have a gauge in the vent to say the temp, before I started, it was 106, add freon and at idle, it went to bout 79-80. AC clutch stayed engaged as well. NOW for the wierd part, wanted to take it for a quick drive to see if it cooled more then at idle, Started to go, now I can hear the AC clutch turning off and on , and the temp is going up to about 86-87. When i stop to turn around, it starts to cool again, dropping to 80, I go back to my house, it starts again, clutch in and out, and temp going up, stop at house, clutch stays on, temp dropping again....

Thats what I got, now Im stuck,lol

 

[Iron Weasel]

OK, so at idle the compressor clutch clicks on and stays on?

When you're actually moving (increasing RPMs), the compressor clutch cycles on and off?

 

[areonic1]

That is correct

 

[Iron Weasel]

Just for comparison sake, I went out and hooked a gauge up to my Explorer....it uses R134a, yours uses R12 unless it was converted.

Anyway, it's about 88° here right now, and the low side pressure with the engine on, A/C off is about 125psi. Turn the A/C on and let it run for about 5 minutes and it drops down to 55psi.

 

[Iron Weasel]

When the clutch cycles while driving, is it fast or slow?

 

[areonic1]

Im using 134 as well, Its converted....Not really fast, like every few seconds.But at idle, it stays engaged

 

[Iron Weasel]

Hrm....

OK, you had about 45psi in it earlier....what's the pressure on it now?

While you're out checking, start the engine up and let it run for a few minutes.

Check the pressure at idle and then while you have someone rev and hold the engine at about 1500 RPM.