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Found Leak With Dye, Nitrogen didn't do it.

extramile on Sun August 16, 2009 2:29 PM User is offline

Year: 1999
Make: Chev
Model: Silverado
Refrigerant Type: 134A

Worked on a chev 99 this week. System was empty so I put 150lbs of Nitrogen in system to find leak and was unsuccessful. Sprayed the whole system while under pressure with soap and water and checked condenser at least 3 times and no leaks. Charged system and injected dye. 2 days later I checked system and dye was emerging from the corner of the condenser. I know for sure I sprayed in that corner when I had it pressurized, why didn't it show up with the Nitrogen ?????

knightgang on Sun August 16, 2009 2:56 PM User is offline

Could be not quite enough pressure. 150lbs static pressure is quite a bit different than 200+ with a comptressor pounding behind it. Must be a very small pinhole in that condensor.

Dougflas on Sun August 16, 2009 7:33 PM User is offline

You should have put an oz or two of refrigerant in the system first and then the N2. Your leak detector would have found it.

daman on Mon August 17, 2009 9:45 PM User is offlineView users profile

I use BOTH dye and my TEK-MATE to find leaks, haven't been stumped yet, dye always comes through.

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'00 Pontiac Sunfire 2200 I4 SFI
'99 Chevy 4x4 Z-71 5.7 Vortec v8 CPFI
'97 Chevy 4x4 6.5 Turbo Diesel 2500
'95 Pontiac Grand Am GT 3100 v6 SFI
'88 Chevrolet Camaro IROC 5.7 TPI(49,000 original miles)

NickD on Tue August 18, 2009 5:54 AM User is offline

Pressure, whether air or nitrogen, 80 % air is only good for a leak down test, need a gauge in the system to make sure it holds pressure over a period of time. Like if you charge it to 150 psi and the next day it leaks down to 149 psi, you have a leak. Can also charge components individually and drop it in a tank of water, problem with this is that many air bubbles will be left on the surface when first submerged that you have to wait until they dissipate, then look very carefully for a tiny bubble forming due to a leak.

Son's HVAC guy came over to his house with a spray bottle trying to find a leak, from estimates, he was leaking refrigerant at the rate of one ounce per month, could only comment, what a waste of time. Came over with my 1/2 ounce per year sensitivity electronic leak detector, it went crazy at one of the fittings at the outside unit and really went crazy in his evaporator. Have to run the system for a few minutes, then shut it down, can't detect those kind of leaks with air blowing like crazy, has to be in a calm area. With a vehicle, best to do it cold as the heat of the engine creates a lot of air flow that even the best detector won't tell what's going on.

EPA lets you waste a can of R-134a to find leaks figuring if you find and repair it, less overall HFC's will get into the environment, but you need a very sensitive electronic leak detector and know how to use it. Must be in calm air and as refrigerant is heavier than air, it's tends to sink down. Soap and water is only good for major leaks, really major leaks. Like over an ounce per hour. System will be bone dry in a day with that kind of leak.

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