Herb

I lose freon quickly but show no leak when I vacuum the system.
I can see using dye that it shows up around the connections to the accumulator but before I changed the O rings I thought I'd
try some A/C stop leak first.
I added the stop leak and a can of 134A
and the gauges were reading properly so off I went with nice cold A/C.

Within twenty minutes the cold air stopped and the light on the auto was blinking which
meant I was Low on freon. I ordered a new accumulator which comes in in the morning but for grins I did a vacuum check and after 1 hour and 30 min the needles haven't moved off the pegs. How can I be losing freon if the system is not showing any leaks?

Cliff Harris

My guess is that it's leaking at the compressor seal, so it only leaks when the engine is running.

Herb

Well, when I use the UV light it doesn't show
any dye anywhere around the compressor.

Churchkey

If no AC oil residue on the system firewall forward the evaporator is suspect.

Suggest having the system leak tested with an electronic leak detector they are a bit more sensitive than the vacuum loss method & will pinpoint where the leak is at.

antfarmer2

You can buy a cheap sniffer they work well for $20

Benny42

Leak testing with vacuum is the poorest method. Pressurize the system and LOOK for leaks. You will find it if it's that big. I agree with above, evaporator is suspicious.

Herb

Well, I'm going to change the accumulator because that's where the dye showed up even though it was changed along with the compressor.
I left the gauges on all night and they were still on the pegs!
I'm thinking when you have a vacuum on the system the o rings are being pulled in but when there is pressure (freon) on the system the o rings are pushed the other way.
I don't know!
I'm just tired of putting freon in it!
guess the electronic sniffer is next if this doesn't work.
thanks for the info!

hcbph

What about using the UV light with it running? Need to insure you have ventilation and dark enough but might see something that way you're not otherwise seeing.

Good luck

antfarmer2

Good chance it is your fill valve easy to change with the right tool. Will not loose freon. And sure you see the dye there but just expect it. Try this low tech test. Put spit in the valve and look for bubbles.

ddahlgren

Vac is 14.5 psi temp difference in the other direction. All the running pressures are at least double that in the other direction.

desertmike1

If your loosing a full system charge in as little as 20 minutes, you have a gross leak. large enough to blow bubbles with a soapy solution applied..

the problem with both a dye, or a bubble inspection is you can't access all of the possible areas, yet with an HALON leak detector you can sniff around the discharge vents and hidden spots. This may tell you something. Leak testing is a bit of an art that takes a little bit of patience and practice.

first step: is looking the entire system over carefully for signs of oil residue or dye, the next step would be; by mixing a solution of dishwashing liquid and water, spray this over as much of the system as you can access and look for bubbles.. if all that fails then it's time for the sniffer.

keep in mind each and every time you loose Freon, you also loose a little bit of lubricant as well..

Stay away from the stop leaks!!

desertmike1

FYI..

http://www.harborfreight.com/electro...tor-92514.html

antfarmer2

Got mine off ebay $20 works great.

ex-x-fire

You can treat an a/c system like a leaky tire, get a spray bottle & fill it with soapy water & hose it down.