palfer Posted June 13, 2016 Share Posted June 13, 2016 Gave in and took the Subie to the dealer for an A/C leak diagnosis. They pulled out what was left and recharged but could not find a leak. they let it run for about 20 minutes and couldn't spot anything. Service writer was honest and said they can usually see the oil leaking out from somewhere. When they can't they usually diagnose it as the evaporator since that is the one part they can't see. Starting to have intermittent issues with it now. On really warm days (110+), it will work for a bit then stop. Other days it will work just fine. Finally got a chance to put gauges on it today, when the compressor comes on it gets to about 180 psi on the high side and 25 psi on the low. Compressor turns off and pressures change to 150/50 and I noticed the clutch turn very slowly for about a 1/2 turn they she'll click on again. Cycling like this about every 30 seconds. Not sure if the clutch shuddering is due to the system being undercharged or an unrelated problem? Am thinking of trying another shop and see if they are better at finding the leak... Quote Link to comment Share on other sites More sharing options...
winginit Posted June 13, 2016 Share Posted June 13, 2016 i changed all the rubber o-rings on my A/C hoses and refilled the system and has been working great at a steady 43degrees. Quote Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted June 13, 2016 Share Posted June 13, 2016 I have read once or twice about weak a/c relays - also, some folks have had to re-set the gap on the clutch so it engages better. also, some folks have had intermittent radiator fans but, that doesn't fit well with your clutch observations. Quote Link to comment Share on other sites More sharing options...
palfer Posted June 13, 2016 Author Share Posted June 13, 2016 Thanks. I've changed all the O rings Quote Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted June 13, 2016 Share Posted June 13, 2016 (edited) are you losing refrigerant? there are bottles of refrig. with dye in them - maybe you have a leak at the condenser or ???? often, using a vacuum pump on the system , in addition to removing moisture, can determine if there is still a leak. Edited June 13, 2016 by 1 Lucky Texan Quote Link to comment Share on other sites More sharing options...
palfer Posted June 13, 2016 Author Share Posted June 13, 2016 Yes, I have been. I've used the dye, can't see any discernible leak however. I've vacuumed it down and it does hold but over time I keep losing refrigerant. Frustrating. I hate the idea of swapping the evaporator per the dealer's logic but not sure what else to do Quote Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted June 13, 2016 Share Posted June 13, 2016 I suppose it could be the guts of the schrader valve. Those and the o-rings are common leaks. And if the vacuum pump is using the leaky schrader valve, it certainly wouldn't show as the leak! a pro may be needed - there ARE refrigerant sniffers you can buy aftermarket, but I don't know how accurate/sensitive they are. If the evaporator was leaking, I guess it would detect that at an a/c vent but I have no experience with that. Quote Link to comment Share on other sites More sharing options...
mkc1962 Posted June 13, 2016 Share Posted June 13, 2016 (edited) I dont know if you have nitrogen or maybe even argon at your disposal. BUT when I have stubborn such ac systems I pressurize the system with either of the two. (have even used dried air on occasion, but air can contain moisture) I take the system to about 50-70 psi. Then I make up a squeeze bottle of soapy water and go to dousing all fittings, coils, etc....you WILL eventually see bubbles somewhere....about the only that is very hard to find is the front bearing seal fo the compressor, but usually on those if that is the case you will see oil residue behind the clutch. It is very rare to have leaks on the internal evaporator coil, but you might where the outside lines connect to the coil. Most cars now adays have even those external to the engine bay but your 97 might still be inside the air box.. Change all your orings, be sure to wipe a bit of regrigerant oil on each of them. then try the above. usually on the sniffers you have to be within about 1/2" of the actual leak unless its pouring out. Once you think you have it...put a good 40-60 minute vac on the system Shut the port to the vac pump and let the guages sit for a few hours. What you want to see is zero loss of vac on teh guages, If it wont hold vacuum it wont hold pressure. Edited June 13, 2016 by mkc1962 1 Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted June 13, 2016 Share Posted June 13, 2016 More common place for leaks than the evaporator are the lower corners of the condenser. It will corrode and leak slowly down at the bottom where it's hard to see. Also common for the shrader valves to leak at the service ports. Make sure you have both caps on tight and that both have the rubber seat still in the top of them. On a 90 degree day I would expect to see pressures around 200 on the high side 30-35 on the low. On a hotter day it will be higher. Quote Link to comment Share on other sites More sharing options...
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