Engine Size: 3.0L
Refrigerant Type: 134
Country of Origin: United States
Is it possible for a system to hold vacuum but leak under pressure or vice-versa?
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.
Double lip shaft seals will leak under vacuum if the teflon is damaged- yet the rubber lip will completely seal under pressure- seen it many times if the shaft seal protector tool is not used and the teflon is knicked.......vacuum leaks can take time to show on your gage- don't be in a hurry to charge after a deep vacuum..........
The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......
Thanks for the replies. Reason I ask is that I just replaced the evaporator and the system has been sitting under deep vacuum for about 12 hours with no visible gauge movement. But there is a slight UV dye stain behind the clutch.
I can't rule out that the dye came from previous work on the system. Two shops worked on it without finding the evaporator leak and left a fair amount of dye around the A/C components.
I'm reluctant to install a new compressor without being sure the seal is leaking.
Would a reasonable course of action be to charge the system and see what happens?
Dye there is a pretty good sign your compressor is leaking. You might charge just a couple oz of 134a so you have positive pressure and see if it is the kind of leak that will hold vacuum but open up under pressure. Either wait a couple days and see if the pressure goes down or check with a sniffer leak detector if you have one.
Thanks. Will do.
We've updated our forums!
Click here to visit the new forum
Copyright © 2016 Arizona Mobile Air Inc.