A/C lost all refrigerant at WOT

[fgross2006]

I put in a brand new, not rebuilt compressor 3 years back. With that I also replaced the accumulator, the orifice tube, the switching connector on the accumulator, and the pressure hoses. I didn't change the condenser or the evap core.

It has held its refrigerant ever since the install until yesterday. I drove my daughter somewhere on the parkway and AC stayed cold. drove back to my town, AC still cold. Stopped off for a slice of pizza, came out AC was cold at first but within a block it blew warm air.

Today I added a bottle I got from Autozone with refrigerant, sealer and dye. I rad the car idle for 5 minutes. AC was cool. Took it for a drive around town. AC was cool. Took it on the parkway AC was cool until I hit WOT to pass slow moving car. I felt the warm air immediately.

Obviously I have a problem too big for Can-O-seal. It almost held but as soon as I punched the pedal, that was it. Is there any particular component that takes a hit on WOT? Just wondering before I go to my mechanic.

[gr79]

A start?
http://vb.foureyedpride.com/showthre...C-cutout-relay

[fgross2006]

That's not what my issue is. At WOT our Fox's are supposed to drop AC pressure for a few seconds. I never liked it but I know when its gonna happen and the cold air always comes back after 5 or 6 seconds. Mine just blew out a seal on WOT and dumped all the refrigerant.

[gt pony]

I have a few questions concerning your problems with your a/c, first, what type of refrigerant are you using, secondly, have you checked your a/c pressures with gauges, and lastly, where did the refrigerant escape (what component)?

[fgross2006]

I have a few questions concerning your problems with your a/c, first, what type of refrigerant are you using, secondly, have you checked your a/c pressures with gauges, and lastly, where did the refrigerant escape (what component)?

I had whatever refrigerant mechanics used when they charge the system with the big snap on AC machine. When that leaked out i just used a can of AC refrigerant with a sealer and dye I got at autozone. I didnt check pressure. the can only has a coupler to connect to the low pressure hose. I dont know where it leaked out of. Was hoping to find out if theres a known weak spot that will pop at WOT.

[Tigger]

If you don't have the glasses and light to spot the dye, I would check for oily connections and go from there. Good luck to you.

[gt pony]

I had whatever refrigerant mechanics used when they charge the system with the big snap on AC machine. When that leaked out i just used a can of AC refrigerant with a sealer and dye I got at autozone. I didnt check pressure. the can only has a coupler to connect to the low pressure hose. I dont know where it leaked out of. Was hoping to find out if theres a known weak spot that will pop at WOT.

By the indications of your comments it sounds like you're assuming that the refrigerant leaked out because the a/c stopped working. You need to have the system checked professionally to observe the pressures or lack thereof to begin to pinpoint the problem(s). Based on what I've read so far it's like you're backing into a buzzsaw and now you want to know what tooth hit you first. As a retired professional in this and many other areas associated with auto repair I'm not trying to give you a hard time or be a smart ass but we and I need more info than you've given us. As it stands now I think there may be an electrical problem and/or a combination of that and an overcharge condition.

Try this, start the car and turn on the a/c and observe if the a/c compressor clutch engages.

After further thoughts I'm editing this post and adding some initial diag. tips. If the a/c clutch does not engage take a test light and check for power at the clutch cycling switch on the accumulator, check both terminals, there should be power on only one.

If there's no power at the switch check the fuses in the fuse box I believe it is the number 6 fuse but check them all anyway with the key on.
If the fuse(s) check okay there is a a/c controller under the dash below the steering column on the shake brace I believe for that year, it should have a 7 or 8 wire connector plugged into it. Let me know what you find and we'll go from there.

Btw, I'm assuming that your system was converted to R134a 3 years ago based on your prior posts and the fact that you used a can with dye that you bought from Autozone.

[fgross2006]

By the indications of your comments it sounds like you're assuming that the refrigerant leaked out because the a/c stopped working. You need to have the system checked professionally to observe the pressures or lack thereof to begin to pinpoint the problem(s). Based on what I've read so far it's like you're backing into a buzzsaw and now you want to know what tooth hit you first. As a retired professional in this and many other areas associated with auto repair I'm not trying to give you a hard time or be a smart ass but we and I need more info than you've given us. As it stands now I think there may be an electrical problem and/or a combination of that and an overcharge condition.

Try this, start the car and turn on the a/c and observe if the a/c compressor clutch engages.

After further thoughts I'm editing this post and adding some initial diag. tips. If the a/c clutch does not engage take a test light and check for power at the clutch cycling switch on the accumulator, check both terminals, there should be power on only one.

If there's no power at the switch check the fuses in the fuse box I believe it is the number 6 fuse but check them all anyway with the key on.
If the fuse(s) check okay there is a a/c controller under the dash below the steering column on the shake brace I believe for that year, it should have a 7 or 8 wire connector plugged into it. Let me know what you find and we'll go from there.

Btw, I'm assuming that your system was converted to R134a 3 years ago based on your prior posts and the fact that you used a can with dye that you bought from Autozone.

Theres no electrical problem because the compressor kicks on and functions fine when theres refrigerant in the system. When I refilled, it worked for a few hours. Because it ran well for 3 straight summers I'll assume it was set up correct the first time. What my mechanic found today was a fast leak out of the high pressure connector. He suggests changing both connectors which we will do tomorrow. Other than that no dye leaks spotted anywhere in the system,

I wasnt asking for a complete diagnosis via the forums. i know AC is complicated. I was only asking if anyone had any knowledge of weak points that would blow out on WOT as mine did twice in 2 days. Now I know.

[fgross2006]

So my mechanic replaced the high and low pressure fittings, vacuumed and filled the system. So far its holding.

[fgross2006]

Just an update on this. After replacing the high and low pressure fittings , purging and filling the system I lost AC that same day after leaving the mechanic. Next day it was mysteriously working again. It functioned and failed for days after.

My mechanic said he thought the low pressure switch was failing. I tried 2 four Seasons #36676 which is for r134a and both would not power up the clutch.

I went to Parts Authority and got a Global Parts 1711326 which is not specific to r134a or r12 and doesn't cross reference to an 84 Stang but it works. Been running cold with no clutch failure 2 days now.

[JACook]

On the CFI engines, the compressor clutch is partially controlled by the ECU, via a relay. The ECU will always
drop the compressor clutch at WOT.

If this problem happens again, rather than just replace parts, try measuring the voltage on both sides of the
LPCO switch. That will tell you whether the switch is getting voltage, and passing it on to the compressor clutch.
A ~$15 digital meter will pay for itself the first time you don't replace a good part with one that may not be as
good as what you had. Or overcharge the system because of a failed switch.

Many LPCO switches, including Motorcraft, are adjustable to compensate for a refrigerant swap. A switch being
sold for R-12 or R-134a just means they pre-adjusted the cutout pressure for you.

Also I do hope your mechanic advised you to never, ever put sealer in your A/C system again. I will add to be
very wary of refrigerant with the Interdynamics name on the can. Some of them are just refrigerant, but most
contain snake oils that should never be added to any A/C system. Just because someone sells something at
your favorite parts store, doesn't mean it's OK to use it.