A/C leak test with UV dye
04-20-2002, 10:17 PM
#1
Three Wheelin'
Thread Starter
A/C leak test with UV dye
I bought one of those UV dye kits witht the light and the glasses. Works well. I found one minor and one major A/C leak. Only good for accessable areas, but a very good device.
I was also thinking of doing a UV scan of the back seat to see what kind of freak owned this car before me but that is another story.
Greg
I was also thinking of doing a UV scan of the back seat to see what kind of freak owned this car before me but that is another story.
Greg
04-21-2002, 11:59 AM
#3
Three Wheelin'
Thread Starter
I bought mine at the local consumer auto parts store. It is a kit with 3 types of dyes. A/C (R12 and R134 safe), fluids and oils and fuel. There is a need for some presure in the system for the dye to work. about 100 lbs. high side would be sufficient to push the dye through the system.
A electronic snifter would be better since it can sense areas which you cannot see, but the dye kit in my opinion, is a good start. The dye stays in the system and can be benificial in finding leaks which occur in the future.
Quinn, how bad is your leak? does the system still come on? If it is dead, you will want to find the leak and plan to do a bit more.
Once you isolate your leak, it is important to read and understand the A/C tech tip pages on A/C websites, Greg Nichols' site and on this site. It is so tempting to fix the leak and just recharge at home, but there are a few steps to take which will insure a better and longer lasting A/C system. The dye may point you to the source, the fix may be a bit more involved.
Even if you have someone else do the work, a basic knowledge of A/C systems is important.
Be careful with the local shops. I had my system vacummed down at the corner gas station. I noticed that he had Freeze 12 on his charging station. I asked him if he had straight R12 to charge my car with and he replied that they use Freeze 12 for topping off and recharging R12 systems and don't but R12 anymore. I said thanks, but no thanks.
Personally, I will only use straight R12 and have no intention of retrofitting this car to R134. With a tight system, the cost of R12 is a one-time charge ($30/lb X3ish) and possible a top-off every few or more years. It's still cheaper than the conversion and the A/C will perform better.
A/C conversion conversations are like motor oil, coolant and tire conversations. Opinions vary greatly. There is one thing that appears to hold true, and that is that there is no "direct drop-in" replacement for straight R12. This includes the blends. R-12 is R-12. I look at it like this. If you can buy it at the local store without an EPA license, it is not true R12 and should not be dropped into your R12 system.
If you want to go the R134 retro route, it is a comprehensive job requiring system flushing, parts replacement, seal replacement, etc. Don't let anyone offer to top off your system with R134 or any of theabove mentioned blends or thing ending in 12 that is not true R12.
One man's opinion.
Greg
A electronic snifter would be better since it can sense areas which you cannot see, but the dye kit in my opinion, is a good start. The dye stays in the system and can be benificial in finding leaks which occur in the future.
Quinn, how bad is your leak? does the system still come on? If it is dead, you will want to find the leak and plan to do a bit more.
Once you isolate your leak, it is important to read and understand the A/C tech tip pages on A/C websites, Greg Nichols' site and on this site. It is so tempting to fix the leak and just recharge at home, but there are a few steps to take which will insure a better and longer lasting A/C system. The dye may point you to the source, the fix may be a bit more involved.
Even if you have someone else do the work, a basic knowledge of A/C systems is important.
Be careful with the local shops. I had my system vacummed down at the corner gas station. I noticed that he had Freeze 12 on his charging station. I asked him if he had straight R12 to charge my car with and he replied that they use Freeze 12 for topping off and recharging R12 systems and don't but R12 anymore. I said thanks, but no thanks.
Personally, I will only use straight R12 and have no intention of retrofitting this car to R134. With a tight system, the cost of R12 is a one-time charge ($30/lb X3ish) and possible a top-off every few or more years. It's still cheaper than the conversion and the A/C will perform better.
A/C conversion conversations are like motor oil, coolant and tire conversations. Opinions vary greatly. There is one thing that appears to hold true, and that is that there is no "direct drop-in" replacement for straight R12. This includes the blends. R-12 is R-12. I look at it like this. If you can buy it at the local store without an EPA license, it is not true R12 and should not be dropped into your R12 system.
If you want to go the R134 retro route, it is a comprehensive job requiring system flushing, parts replacement, seal replacement, etc. Don't let anyone offer to top off your system with R134 or any of theabove mentioned blends or thing ending in 12 that is not true R12.
One man's opinion.
Greg
04-21-2002, 01:35 PM
#4
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Greg, You are correct. Anything besides R-12 is not as good as R-12. If, someone is looking to shave a few dollars off of a repair. Then the choices are of 2 refrigerants. One is called 'Hot Shot' the other is MP-39. Both refrigerants are a blend. They both are compatible with the original oil used for R-12. Both will not react corresively with the oil and the metal hose linings.
The inside scoop is; need to recover, or make the a/c the system flat (environmentally correct Recover). Then vac the system down as close as you can to 29.99 vac. Charge the new refrigerant from a liquid state(charging as a gas will let the blend seperate and make a new refrigerant) slowly with the compressor off, till the temp/pressure is above freezing. Now, you can let the charging go at it's own pace. Kick on the compressor and finish the charging to spec. The 2 refrigerants run a 10% higher head pressure, so you need to charge 10% less than your cars capacity. Or, you can charge your system by pressure, or by the amp draw of the compressor. I recommend charging by capacity.
I do work in the refrigerant field, as I see it using one of the two is the way to go. If you can not get R-12 as low as $10.00/pound.
Dozman
'85 928 Auto, Black
The inside scoop is; need to recover, or make the a/c the system flat (environmentally correct Recover). Then vac the system down as close as you can to 29.99 vac. Charge the new refrigerant from a liquid state(charging as a gas will let the blend seperate and make a new refrigerant) slowly with the compressor off, till the temp/pressure is above freezing. Now, you can let the charging go at it's own pace. Kick on the compressor and finish the charging to spec. The 2 refrigerants run a 10% higher head pressure, so you need to charge 10% less than your cars capacity. Or, you can charge your system by pressure, or by the amp draw of the compressor. I recommend charging by capacity.
I do work in the refrigerant field, as I see it using one of the two is the way to go. If you can not get R-12 as low as $10.00/pound.
Dozman
'85 928 Auto, Black
