Automotive Air Conditioning Information Forum (Archives)

Provided by www.ACkits.com

We've updated our forums!
Click here to visit the new forum

Archive Home

Search Auto AC Forum Archives

Expansion Valve

Gerald K4NHN on Fri September 12, 2008 7:36 PM User is offlineView users profile

Will an Expansion Valve at ambient temps have any flow of air through it or will be totally closed off.

Gerald K4NHN
Cayce, SC

mk378 on Fri September 12, 2008 7:56 PM User is offline

It should be open, assuming the pressure sensing port is open to the atmosphere at zero psig.

Edited: Fri September 12, 2008 at 7:57 PM by mk378

Gerald K4NHN on Thu September 18, 2008 8:11 PM User is offlineView users profile

mk378
You may have answered my question fully but here is what I have in the 82 Chevy Luv diesel that I'm working on. It's the first AC that I've had to really get into that uses an expansion valve, and I'm not sure about the evaporator unit. I'm guessing that the inside is like the pictures that I'm encloseing. I don't see any place for a orifice tube to be in the line, so the expansion valve must all be inside like the pictures. The picture show an external equalizer line coming off the Expansion valve. I want to flush everything that I can before I start sealing it all up, but there isn't any air flow either way in or out of the lines going into the evaporator unit. I'm trying to not have to take that unit out from under the dash if I don't have to. Do I need to do anything on the external line to make the EP to open up or am I ready to go with the vacuming down. I noticed that when I opened the system up, that the pressure came off the high side and the low side still had pressure. After the high side was gone I then opened the low side to get the pressure off of it.. I thought that was odd. Was it. I'm open to alll suggestions about this..

http://home.usit.net/~gcromer/Chevy%20Luv%20evaporator%20a.jpg

http://home.usit.net/~gcromer/Chevy%20Luv%20evaporator%20b.jpg

Gerald K4NHN
Cayce, SC


mk378 on Fri September 19, 2008 12:19 AM User is offline

I think you need to replace the TxV. Sounds like it is blocked. This should be a typical Japanese design where you can readily take the evaporator box out after removing the glove compartment, without disassembling the whole dash.

You cannot flush through a TxV regardless. The evaporator needs to be disconnected and flushed seperately. Even with a good valve, you can't get enough air flow through it to effectively blow the flushing agent out of the evaporator.

Note that the equalizer line is just used to sense pressure. There won't be any flow should you test by blowing into it.

Back to Automotive Air Conditioning Forum

We've updated our forums!
Click here to visit the new forum

Archive Home

Copyright © 2016 Arizona Mobile Air Inc.