Automotive Air Conditioning Information Forum

Got the car recently and the system had just a few psi. Vac for 15 minutes and waited another 15 and it held near -30 psi, so vac'd another hour and charged to spec so that the a/c blows ice cold. A week later it's still ice cold. A month later, nothing. Gauges at a few psi. Put in a half pound r134 for leak testing. Using a Mastercool IntellaSense leak detector. Get no hits under the hood along the condenser, around the compressor and across the lines. Go to check the interior, and soon as I open the door the detector goes off. Not so much at the vents but just inside the cabin. Evaporator leaking? How hard to replace on this model?

Evap definitely leaking unless the fittings are not tight, which is unlikely. To be sure, sniff the drain tube under the car. 134 is heavier than air. If drain tube wakes up the sniffer, then that confirms the evap.

'95 "N" car evaps aren't too bad- I've done a dozen or so. The drain pan comes down, the heater core is removed and the evap comes out, there are about 13 5.5mm screws (brass-colored) that need to be removed- most mechanics only put about 8 of them back in- thats how I tell if evap has been replaced before. Two or three of those screws are a PITA to get to. I've seen cracked drain pans where it was ripped out because of a tight area to work. Nobody over 250 lbs can usually get one out laying upside down under the dash.

Don't let sniffer get water in it from an active drain tube-- will take a couple of days for it to work right again once it drys out. I always make sure there is dye in the system. I add dye to all my reserve oil - so that every car gets a dose of dye when I add oil. Then I collect the drips from the drain tube in a clear glass mason jar- and view the green tint in the water- or to be sure- pull the drain tube (elbow) off and shine your black light inside of it-- to be absolutely sure evap is leaking. Most of the time you can actually smell the oil/refrigerant unique smell inside the cabin of a fresh recharge when evap is bad. Just evaluated a smelly Pontiac sunfire last week for bad evap.