Fox_

I've had a slow refrigerant leak for awhile now.

I confirmed low refrigerant levels with a set of gauges and confirmed operation of the compressor. Since the level was not low enough to trip the compressor cut off I injected ~1/4 ounce of UV leak detection dye. I ran the compressor long enough to circulate the dye in the system.

I've found all of nothing other than where I injected the dye.

Looking at it, I don't think I want anything to do with resealing the entire system at the moment. Leaning toward evacuating the system, recharging, and seeing what happens. However, dealing with r12 makes all of that a PITA.

Thoughts?

Speedtoys

Where didnt you look for the leak?

And how much time did you give it?

Time since the last confirmed fill?

The Forgotten On

^^ This. I would also get a freon "sniffer" and use it near the inside vents. You make have a leak in a evaporator.

You could also have a leak under the passenger side seat where the solenoid valve for the rear AC is located.

FredR

The worrisome bit about leaks is when you cannot see where they are leaking from [i.e. the evaporator].

When you have a slow leak and it takes a long time for the system pressures to drop not too surprisingly the oil leakage rate is also very slow.

Maybe time to get an ac shop with a sniffer to test for you before doing anything else.

FredR

If he has one

Fox_

I ran the compressor ~30 minutes, I'm going to recheck with the light in the morning.


No idea the last time it was charged.





Mention "r12" and "Porsche" and all the local shops start whining.




What I'm worried about.

...and yes it has rear AC.

SteveG

?? This would seem to be key here, everything about a/c issues needs numbers. If you are only topping it off once every two years or less often, perhaps?, then you are chasing what I would term a very small problem. And I'm one of those that thinks we need to be concerned about the ozone. But eventually, you don't know how much oil is left in the system and you need to have it drained, flushed, replace dryer, recharge by weight.

Your options are: convert the system to 134, or establish how much it is leaking and track the problem -- at some cost, maybe a lot of cost. If the leak is small which would seem to be since you don't know when it was last filled, then I would get the EPA certificate (easy) and get 12 oz R12 cans off ebay.

Lots of discussion here on merits of r12 vs. 134 and stop leak "additives" that supposedly are compatible with R12.

They don't want to contaminate their equipment ($$$$) so they simply don't touch R12. Perfectly understandable on their part.

Good luck.

Speedtoys

Ya, 30min is nothing.

Run the AC for a few weeks, then go hunting.

Fox_

Not applicable without a recharge.

I don't want to damage the compressor.

Anyways,

Evac, recharge by weight, see what happens seem to be the best path for me. Dye should help if the problem reappears.

Speedtoys

??

If you are not triggering the low pressure sensor, you're not going to damage anything. You're going to refill the system with R12 twice to fix the leak?

I get what you're concerned about..but the only issue is that it wont get as cold as you like...but you will find your leak.

Fox_

Other than mildly interesting photos of the mess where I put the dye in and the sightglass, the UV dye didn't turn up anything.

Not that I'm surprised.





I considered converting to 134a, but to do it "right" doesn't seem reasonably feasible.

Getting to get lines running from the compressor that are buried does not look fun.

Speedtoys

In 30min a multi-year leak isn't going to expose itself...needs more cycle time to find it.

FredR

How did you get the dye into a live system as a matter of interest? I have piece of kit for doing that as well as adding oil to the system but could not figure out how to do so without the risk of admitting air as well. I have also seen a piece of kit like a hypodermic syringe for doing such activity.

Fox_

Screw/twist type injector.

Filled, pressurized, and burped it with a screw driver to clear the hose.

I had similar concerns. It's possible a very small amount of air was included, but the plan was and is to fully evacuate the system.

dr bob

Better electtronic sniffers claim they can detect leaks at the "grams per year" level. The technique for that includes wrapping each connection with plastic wrap with the probe inside, letting the refrigerant accumulate in the somewhat captive wrap for minutes. Realistically, a "grams per year" leak doesn't show up in a year of system use. Point is though that it's a lot faster and easier to find leaks with a sniffer if you are determined.

Using the dye is an OK way, but it requires that you sanitize the areas around every possible connection point and other leak spots. Great where connections are exposed so you can see the dye with a blacklight. Great where you can add the dye, go drive the car for a day, a week, and a month. Long enough that the leaking refrigerant to carry some oil out, since it's the oil that carries the dye. Then find it in the dark.

Pick a good sniffer. I dislike the ones that auto-zero, if only because they seem to continuously auto-cal while the probe is stuck inside the plastic wrap.for the tiny leaks. Be aware that the sensors on the snifferes have a limited lifespan once opened. As you look at snifferes, make sure you can get replacement sensor tips for it. Get extras now and stick them in the freezer, sealed in their little foil packets.