Re: [DML] finding freon leaks

["Walter" <Whalt@xxxx>]

The symptoms of my leak is that the a/c was first working fine. Then I let
the car sit for nearly 3 weeks while I took my time replacing the trailing
arm bolts and the front springs & shocks. After that my a/c compressor
wouldn't kick on. I put a gauge on the low side and read 45 psi which
according to the manual should be at least 60 psi. So I put a 24oz can of
freon in there. This brought the static pressure up to around 75 psi. I
since drove the car to the SEDOC cruise in (about a 7 hour trip) and the a/c
worked good, but I was driving at night. The compressor would stay on
continuously at idle and cycle at 3 to 4 second intervals at higher RPMs. I
didn't know enough about a/c systems to know if I had too much Freon in
there or not enough. DMC Joe helped me out. He put a gauge on there and
watched it cycle and said that it was still too low. The manual doesn't
explain how to top off a low system. Instead it just says to suck it all
out and start over. That is fine if you have freon recovery equipment
handy. But most of us don't. Joe explained that a properly charged system
should cycle on for 7 seconds and rest for 4 seconds at 2000 RPMs. He said
to add just enough R-12 or Freeze-12 to the system until it starts cycling
at this rate.

On the way home, the a/c just wasn't keeping up with the sun load, so I put
most of another can in there. I have never had much luck getting gas out of
one of those cans without using a heat gun to boil it out. I ended up
sticking the can over the exhaust for a while to keep it warm. This got
enough freon in there to keep me cold the rest of the way home. When I got
home, I used a heat gun to get the rest of the freon out of the can and into
the system. Those cans leak a lot after you open them, so I figured I might
as well dump it in rather than waste it. Now the compressor cycles at
around 9 to 13 seconds at 2000 RPMs, so I figure I have too much gas in
there.

Now I'm not really sure if I have a leak. I understand that leaving a car
sit for as little as a week will allow the compressor seal to dry out enough
to start leaking. Now newer cars will run the compressor for 20 seconds or
so every time you start the car to keep the seal lubricated in case you
never run the a/c.

Since last night, I learned a lot about how freon sniffers work. The first
one I bought yesterday was defective. It had already been out of the
package and fooled with by someone else. After a while it totally glitched
up and wouldn't do anything but beep wildly. Before it was sensitive to
temperature changes (hence triggering when putting it up my shirt sleeve.
The new one ignores my smelly arm pits.) I have learned, however, that
these sniffers are sensitive to fuel odors, so that is why I was getting a
positive reading around the fuel tank. I don't have any remarkable leaks
there, but these units are very sensitive to such things. I can't explain
the positive reading I was getting from the condensate drain with the old
sniffer. But the new sniffer doesn't detect anything there. I was getting
a reading off of a bend in the rubber hose at the frame going to the
accumulator, but not now. Perhaps it only leaks from this hose (the high
side) after the a/c has been running a while. Or maybe I was picking up a
fuel odor.

Thank you all for your suggestions so far. I will consider the dye as a
last resort. I don't want to put it in there unless I really have to. I
don't think my Schrader valves are leaking. I removed the brass caps and
got a positive reading, but then I also got a positive reading on the same
spots on my 3 year old truck which hasn't been touched since it left the
factory. I blew the area clean with shop air and didn't get a reading
afterwards. I got a spray bottle of soapy water, so I'll use that along the
hoses to confirm any leaks. I hate to go to the trouble to replace those
lines, but if that's what it takes then I don't have a choice.

I'll keep y'all posted as this story unfolds.

Walt Tampa, FL