Automotive Air Conditioning Information Forum (Archives)

Provided by

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

Archive Home

Search Auto AC Forum Archives

Need help Identifying Item

clindahl on Mon May 31, 2010 5:49 PM User is offline

Year: 1993
Make: Ford
Model: Aerostar
Engine Size: 4.0
Refrigerant Type: 134a
Country of Origin: United States

Hello! I have a 1994 Ford Aerostar that has a leak on the line set that goes to the compressor. After having the system evacuated I was able to take the line set off and see what is going on. The fitting on the right side of the block is okay, and from what searching I have done that is the over pressure release, i.e. if the system were to get to 450+ PSI that would let go. That one is not leaking. The one that IS leaking is the brass fitting with the little yellow X on the top. It will hold a vacuum all day long, but as soon as the smallest amount of pressure is introduced it will hiss. If I push my thumb on the top it stops, but as soon as I let go it starts hissing again. What is this thing?


JACK ADAMS on Tue June 01, 2010 12:08 PM User is offline

By surprise, this is a Low pressure relief valve. Why Ford did this is a surprise to me. The part is available by Ford Only, Part# F4TZ-19D644B sells for about $30.00 special order.

clindahl on Wed June 02, 2010 7:06 PM User is offline

Thank you! That is very interesting indeed why Ford would put a low pressure relief valve. Oh well - now that I know what it is I can replace it Thanks again!

mk378 on Wed June 02, 2010 9:39 PM User is offline

If it's leaking around the base, you may just need to unscrew it and fit a new o-ring. Leaking out the hole in the side you would need a new one, or some way to stop it up permanently.

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.