no refridgerant in a/c

pastaroni34 · #1 (**permalink**) 08-30-2007, 07:31 AM

So where should I start looking for leaks? Its not a slow leak, its something major as my pressure reads absolute 0. Any common issues here? It worked until we changed the clutch, what could I have broken? lol. I will pull the compressor also since the front pulley looked a bit wobbly.

**lowmileage** · #2 (**permalink**) 08-30-2007, 07:57 AM

You probably know (I hope) to not run it without refrigirant as it acts also as a lubricant.

goatster · #3 (**permalink**) 08-30-2007, 08:09 AM

The trinary switch won;t turn the compressor on unless it sees pressure so good there!

Jason it could be leaking from lots of places-- first thing to do is pull a vacuum and see if it holds --- you can maybe tell where the leak is but likely not. Next thing you can do is get a dye charge, throw it in and pressurize the system and see where it leaks out.

bob

andrewg · #4 (**permalink**) 08-30-2007, 09:49 AM

A vacuum test could tell you a lot, but try using nitrogen to pressurize the system and listen for the leak. If you do not have a vacuum pump they can be borrowed from autozone. If you have the time, you can come by the shop and borrow my air compressor powered vacuum pump.

pastaroni34 · #5 (**permalink**) 08-30-2007, 12:29 PM

Andrew,
my friend here in college station is an a/c tech. We have access to a vacuum pump, also since I am in the physics department about 2000 liters of liquid nitrogen

Thanks for the tips

-Jason

Alfisto Steve · #6 (**permalink**) 08-30-2007, 12:55 PM

Quote:

Originally Posted by pastaroni34

Andrew,
my friend here in college station is an a/c tech. We have access to a vacuum pump, also since I am in the physics department about 2000 liters of liquid nitrogen

Thanks for the tips

-Jason

andrewg · #7 (**permalink**) 08-30-2007, 07:12 PM

I wish, I could take credit for the nitrogen tip, but Chris @ Ray's Auto Electric showed me that tip. A nitrogen bottle is cheaper than dumping freon into a system, only to have it leak out.

pavanbabut · #8 (**permalink**) 08-31-2007, 07:54 AM

Quote:

Originally Posted by pastaroni34

So where should I start looking for leaks? Its not a slow leak, its something major as my pressure reads absolute 0. Any common issues here? It worked until we changed the clutch, what could I have broken? lol. I will pull the compressor also since the front pulley looked a bit wobbly.

andrewg · #9 (**permalink**) 08-31-2007, 11:06 AM

I know Autozone rents them. I would expect that most of the big parts suppliers will also rent them. Industrial welding supply shops should be able to rent you a nitrogen tank. You put the AC system under constant pressure and listen for the leaks. Using nitrogen has never let me down. You could also inject a little oil/dye combination with some freon and use the black light if is it easier. Good luck.

pavanbabut · #10 (**permalink**) 06-26-2008, 08:49 PM

Is there a way to test whether the pressure switch is working or not??

**gprocket** · #11 (**permalink**) 06-27-2008, 06:29 AM

Check that you are getting voltage at the gray-black wire. If true, check that you are between min and max pressure with a gauge. If true check that you are getting voltage at the green wire. If you are not then the switch is bad.

MrT · #12 (**permalink**) 06-27-2008, 06:47 PM

It cost me $48 to have an A/C shop check my wife's '92S to find that the evaporator(in the belly of the beast), the high pressure hose, and the compressor all leaked. But you never know just how carefully the leaks were localized. Could be connections, I guess. I'll make the acquaintance of the internals of the compressor sometime soon, I guess.

But I thought the $48 was acceptable as a diagnostic cost.