Empty/leak......Dye

[Jonny525]

hello all , I have a 95 dodge neon that have a leak in the ac system. I connected an ac manifold to it and the static pressure on both gauges read zero. The ac worked last summer but now, as the days r warming up its blowing hot . I would like to add a dye to the system to find the leak. I have both the liquid dye and also the dye that come in a can . How do I get the dye into the system ? and also which one is better to use . I am almost certain the evaporator is leaking because when the ac was working u could smell a faint refrigerant from the air duct. Do i need to vaccum the ac system to get the dye in a can in ..........or would it be better to use the liquid dye instead ?

[Cusser]

I'd say the issue to consider first is that it's not that easy to see a leak in the evaporator area with dye because it's enclosed in a plastic case. You'd be limited to looking for dye in the condensate drain. You may want to have a shop troubleshoot this leak for you; an electronic detector (sniffer) in the vents or in the condensate drain tube typically is used for leaks in that area.

OK: your original question: how to add the dye? Well you need dye and refrigerant, the refrigerant will circulate the dye as you run the system a bit. So the choice would be refrigerant that contains dye, of your two stated choices. You'd likely need at least two cans (one could be plain refrigerant) to get the unit operational, so the dye can circulate and you might be able to see any leak with UV light and special glasses. Never use sealants or conditioners in an AC system.

So, you add the two cans, and actually find the leak. Then your two cans are "lost" unless you have a way to recover the refrigerant, as dispersing/venting into the air is illegal.

So, when all that is taken into consideration, I think a specialized AC shop is better idea.

[Jonny525]

Thank you Cusser for the quick and informative reply. Just for personal information....... to introduce the 2 cans of refrigerant (dye included) into an empty system does the ac system need to be vacuum 1st ? Yes or no ?

[Cusser]

Great question.

My own opinion, and opinion only. If one KNEW that this would only be used for leak finding, with no plans to recover the refrigerant, would probably be OK.

But what if you do that, and find it is only a connection that needs to be slightly tightened, that has loosened from vibration? If you had evacuated the system beforehand, you could simply tighten a hair to stop the leak, add correct additional amount of refrigeration, and be on your way. If you don't evacuate first, you'd need to re-do.

Doesn't AutoZone have loaner vacuum pumps and gauge sets?

[Jonny525]

I was gifted a manifold and a vacuum pump and a bunch of other auto tools from my ageing father-in-law. So i do have that. So i guess u are telling me it is better to vacuum the ac system 1st. Then check to see if the ac system holds a vacuum to determine if there is a leak in the system or not. If the vacuum does not hold i am taking it that it would be hard to find the leaking spot with out a dye. So i guess i should add the dye and refrigerant after and give it time to work it self thru the system . To see where the dye leak out. Am i right ?

[Cusser]

I was gifted a manifold and a vacuum pump and a bunch of other auto tools from my ageing father-in-law. So i do have that.

Great - you're way ahead of a lot who post here.

ISo i guess u are telling me it is better to vacuum the ac system 1st. Then check to see if the ac system holds a vacuum to determine if there is a leak in the system or not.

Yes, vacuum it, better. But remember the system is designed to hold refrigerant in. But still - a leakage test can be a decent indicator.

If the vacuum does not hold i am taking it that it would be hard to find the leaking spot with out a dye.

Not necessarily. I found the hole in my own evaporator (right in the center) in 2002 using plain old soap bubbles, as it still had some refrigerant in the system. I had taken out a plastic duct part and had access.

So i guess i should add the dye and refrigerant after and give it time to work it self thru the system . To see where the dye leak out. Am i right ?

Yep add some refrigerant, use dye, soap bubbles, whatever works. Check hose connections, crimps, compressor seal, etc. Yes, and some makes/models have more issues with evaporators leaking than others.

[Jonny525]

one more question , what design is a 10PA17C Compressor? is it a vane, scroll or a piston type?