just another A/C thread.

[truckintim05]

When I bought my truck just over a year ago the A/C didn't work, and I figured it was just a leak. This summer I decided to tackle the problem and replaced the compressor lines. I could see where oil was leaking from the schrader valves. I recharged the system, and cleaned out the blower motor, etc. All was chill for about a week. Now there is no refrigerant again. Next I refilled with some r-134 with the dye in it. The a/c blew cold, but there was no sign of any dye ANYWHERE. Once again the refrigerant is all gone. I've looked top to bottom, front to back with a UV light and I can't find ****.

Anyone know another common place for leaks that won't be apparent with the dye? Since middle of june we have not had a day that has not been over 100*.

 

[Marcos]

Evaporator core under the dash maybe?

I had a leak, it was coming from the front compressor shaft seal so I could never see it since it was under the clutch.

I jsut used some super seal, **** works.

 

[truckintim05]

Evaporator core under the dash maybe?

I had a leak, it was coming from the front compressor shaft seal so I could never see it since it was under the clutch.

I jsut used some super seal, **** works.

I hope its not the evaporator core. Looks like a total ***** to pull that out. Do you really think that sealant stuff with work on a fast leak like this?

 

[Marcos]

Depends on the truck, my trucks compressor was leaking and is runs about 130 bucks, so I decided to just try super seal, its not the stop leak kind, its some nasty stuff if you use it incorrectly.

http://www.idqusa.com/proddetail.php?prod=325

 

[truckintim05]

I took the plunge and decided to inspect the evap core thoroughly, and pulled my entire dash. Now I'm down to the heater box and can't figure out how to get it out of there. I got one bolt going into the firewall from the inside, two bolts directly behind the engine block going in, and three that were behind the coolant overflow. To take the box out, will I have to remove the heater core, and does that mean I need to drain coolant?

A mechanic friend of mine was almost certain the leak was in the evaporator, so I ran with it. Hopefully it won't be a waste of my time. Pulling the dash sucks.

 

[truckintim05]

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So I went ahead and installed a new evaporator core. I got it changed out without having to remove the heater lines. After I reinstalled all the HVAC electronics I refilled with a can of r-134. Now the compressor won't engage. I figured maybe there was not enough pressure for it to get started so I tried another can. There seems to be plenty of pressure, as nothing changes and the pressure in the lines will not rise.

any ideas?

 

[SAATR]

The most likely scenario is something isn't plugged in, such as the low pressure switch, the compressor clutch coil connector (say that three times fast!), or a connector on the control head. I forget if the button or something on the control head lights up when you turn the A/C on in the old style dash, but if it doesn't/isn't then you're going to be looking for the control head or the low pressure switch to be disconnected, or possibly another subharness under the dash.

Aside from that, you could have broken the control head or one of the said switches, in which case you would need a replacement. Quick check for the low pressure switch is to jump across the pins and see if the compressor kicks on. If you know there's freon in the system and compressor runs, then you have a faulty switch.

If all else is working, then check for voltage at the compressor clutch coil connector. If it is present, you either have a faulty ground or a faulty clutch.

Any current info to add?

 

[truckintim05]

I'm back in business now. I took it to a local garage to have the air evacuated, and the proper amount of refrigerant added. He also made sure there was the correct amount of oil present, because I surely lost a lot changing all that out. We thought there may be a bad pressure switch as well, but after a good charge everything was fine.

 

[SAATR]

Ahhh, the old "not-enough-refridgerant-to-turn-the-compressor-on" excuse . Just kidding with you dude, glad it worked out!

 

[Toms94z71]

yeah air in the ac system causes all kinds of issues, you did the right thing getting it vacuumed out.