tckitt13

My 2006 MegaCab diesel lost the AC on a trip. I put a can of refrigerant in and it worked for about a half hour and quit again. I suspected a leak so I bought a set of gauges to check it out. After sitting without being driven for over a week I hooked the gauges up without starting the engine and was surprised to see about 100psi on both the high and low sides. When I started the truck and turned the AC on the compressor would kick in then right back off suggesting that the system is low. I don't want to add freon if there is a leak, so my question is:

If my system had a leak shouldn't the static pressure be zero or very close to it after sitting that long?

Where in the system would the freon only leak while the compressor is running?

Thanks for the help guys

ftltmp

What were your pressures with the truck running? Is your fan clutch working?

markqti

had the same problem, still no fix. wait until payday I guess

tckitt13

Pressure we're indicating low charge as I said. And compressor was clicking on then odd as I also stated.

I appreciate the attempt to help but really just am looking for answers to my two questions. If anyone has answers to those questions it would be a big help.
Thanks

BigIron70

Most likely the evaporator is leaking. If you have R134 sniffer check the vents when ac is on. You can also inject dye into system and check with black light and special glasses. Best to take into shop that specializes in ac repair if you do not have leak detection equipment otherwise you maybe just guessing. If the evaporator is leaking it can be pricey to replace since dash will need to be puled. Good Luck.

Stamey

Your AC system has a "static" pressure in it, from the freon at rest. It will be 70-100, or so, PSI. This is normal. When the compressor is running you will have much lower pressure on the low side vs the high side, 35-55 psi on low and 175-300 on high. When the compressor is off the low and high sides equalize.
To me, somewhere on the high side could have a leak when the system is running, as the pressure is so high there, and whatever sealing point that has failed may only fail at high pressure. That's the only reason I can think of for it to leak only while running.
The high side is from the compressor to the condenser and back out to the orifice tube, located behind your passenger battery box.
I'd put some UV dye in it, run it, then go over everything with a black light.

Chris