Either a leak or non reliable leak detector--need advice

msg on Sun October 05, 2014 11:10 AM

Year: 1963
Make: Chevy
Model: Chevy II
Engine Size: 194
Refrigerant Type: R12

After installing an original factory rebuilt AC system recently, I went looking for trouble with a newly purchased leak detector tool off Amazon and may have found it today.
I started testing with the Signstek Portable AC Refrigerant Gas Leakage Detector Tester with High Sensitivity leak detector and it started chirping when I poked it into the vent of the evap case
Here is a link to the tool
http://www.amazon.com/gp/product/B00FYO8UL8/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

I took off the faceplate on the evaporator case and got some soap bubbles and on a brush and started slathering it onto the thermal expansion valve and no bubbles grew from anywhere on it or its connections.

Back before I assembled the system about a month ago I tested the evap with the thermal expansion valve connected and submerged with around 125 psi on it and there were no bubbles then so I assumed the evap was good.

At the time I charged it with r12 I did not add the UV dye which now I wish I had. I did pick some R12 Uv Dye up but wondered first if I am worried over nothing or if I should add the dye and get the goggles and see what I can.

Can UV dye even be added at this point?

mk378 on Sun October 05, 2014 1:26 PM

Possibly a false alarm. Leak detectors can respond to vapors of other things than refrigerant.

There are tools to inject dye under pressure into a charged system.

bohica2xo on Mon October 06, 2014 6:56 PM

I wish more people took the time to leak test like that.

I would agree with 378, probably a false hit. Some sealants outgas solvents that will trip a detector for weeks after they are used. Paint drying nearby, a shop rag within a few feet & a little breeze... those & many more will set off one of my leak testers.

New interior in the car? Fresh vinyl, carpet glue, etc will do it.

-------------------------
"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.

msg on Mon October 06, 2014 7:04 PM

What has me concerned is that the beeping kicks in right when the tip get close to the evap. Before I took the evap faceplate with vents off the front it would trigger it as soon as the tip went into a vent ball.
Now with the faceplate and all off for a few days it only does it as I get it close to the evap itself. And I even dulled down the sensitivity level all the way.

I dont have any new paint. adhesives, epoxies anywhere near this area so naturally im thinking the worst.
Are there any recommended tools/methods to inject the uv dye into the system just in case?

Cussboy on Mon October 06, 2014 10:13 PM

You have the system "open", so just pour in the dye.

msg on Tue October 07, 2014 8:43 AM