Can't find leak after UV dye.

[420benz]

Injected UV dye into a/c system,put 50miles on car and with UV lite could not find any signs of dye anywere. Ran car in garage for 5min. to check cond.from evap. coil,no dye.Now what??? BTW system is putting out 51Deg. temp. Last year i put 1.5 lbs. into system to reach propper temp.

[Kestas]

What pressures are you getting?

[420benz]

Pressures are: 40/44low -138 hi. low side fluctuates between 40 and 44

It may be leaking inside your ac box and you just wont see it with dye until you remove the evaporator. Your pressure definitely indicates you are low on freon. You can use a sniffer to check and see if its leaking inside the box but sounds like that’s the place if you do not see any dye. I would make sure you checked it real through though before you go replacing the evaporator. Good luck

[420benz]

Where is this box located and how do i get to it? Also if i do find freon in this box can i asume it is leaking from the evap. coil?

[ksing44]

For me it took driving all summer, two injections of UV dye, and multiple trips to the shop, to find out that my system was leaking from the condenser. I suppose I was lucky to dodge the evaporator repair. I was told that the dye would have shown in some kind of weep holes, if the evaporator were the site of the leak. They said it could take multiple injections for the dye to show at the weep holes.

Are you using a black light and shooting(yellow) glasses?

Did you shine a black light into the condensation drain water under the car while it was dark?

How bad is your leak? Your pressures sound as if the system is not near full enough. If this is the case it may not be cooling well enough to make any condensation drain water.

Provide as much info as possible.

Good luck,

[420benz]

I bought a Spotgun Jr Injector #331500 which came with sae-j-2297 certified yellow dye. I am using a Spectroline # bib-150b black light [365nm]. I ran car in the garage for 5min. and checked the condensation drips[two drip spots] and no sign of dye. I do not have the yellow glasses but i will get a pair today. Should i put another ounce into the system or put more miles on the car? Last year i had to add 1.5 lbs into the system.I am getting 51deg. out of center vents.

[420benz]

What are the yellow glasses for,safety or better to see yellow dye?

You can see the dye much better with the glasses I would not add more dye just drive it and it will show up.

Yes, you need not add dye. I'm sure there is enough in the system. The yellow glasses do indeed help recognize dye. Sometimes it is hard to find and they help.

I'm concerned that you said that there was only two drops of condensation. Was it not cooling well? It would be nice to have a nice, fat puddle to look at in the dark with your bright light and yellow glasses. When the dye shows up in condensation water it is not as if the water was pure dye. It is in there in a trace amount. You need a strong light, yellow glasses and a dark area. The water will only glow slightly if the evaporator is leaking.

Good luck,

[djcheung]

I had exactly the same problem about two years ago. Tried the UV dye twice but couldn't see anything. Eventualy traced the (small) leak on the inside of the condenser, in between the water radiator and ac condenser so it was difficult to see.

[420benz]

Larry: I am getting [two drip spots] both about 4in. in dia. It is about 80 deg. in Ga. every day with an overcast, not very hot. I am getting 51 deg. out of the center vents. I can see merky bubbles in the sight glass.It is cooling enough now,but when it gets up to the 90's the cooling will stop.

djcheung: I was wondering how to find a leak behind the cond. coil. How did you find it?

[djcheung]

At first we used the UV light but couldn't find anything obvious. Becase it wasn't a big leak, small but big enough to leak out completely within a month. We started looking from underneath the car rather from above. Found a small trace of UV dye between the two radiators. Took the water radiator off and found there were a lot more UV dye there. Replaced condenser and all still working now.

[420benz]

djcheung: How much dye did you inject,and how many miles did you put on the car before you found the leak?