f1anatic Posted July 7, 2007 Share Posted July 7, 2007 Howdy... I feel compelled to add a little A/C refrigerant to my system. Compared to the A/C performance of other local members, mine seems a little weak. I kept looking at the vacation pictures and seems a little confusing. I have recharged the A/C on many cars before - I know all about the little hose and how you connect, puncture the can...etc etc I just want to make sure that the LOW pressure port is the one closer to the windshield and marked with a gray cap with L on it. The other HIGH pressure port (and not to be used) is closer to the radiator and the cap is gray but not marked H. I looked up in the vacation pictures but the diagrams were not very clear. I wanna make sure I get it right before I burst the HVAC system and the can in my face. I plan on adding the smallest size can - it is about 4 ounces. Link to comment Share on other sites More sharing options...
mwiener2 Posted July 7, 2007 Share Posted July 7, 2007 That's not how AC systems work. Just adding the "smallest" can is a very dumb thing to do. If you are concerned about your AC, take it to a pro. My Mods List (Updated 8/22/17) 2005 Outback FMT Running on Electrons Link to comment Share on other sites More sharing options...
rao Posted July 7, 2007 Share Posted July 7, 2007 The ports are different sizes so that you don't mess up. The high pressure hose (which goes from the condenser) is smaller diameter and the low pressure hose (coming back from the evaporator) is larger). Rob IF YOU CARE ABOUT YOUR CAR YOU SHOULD NEVER DRIVE IT Link to comment Share on other sites More sharing options...
PhilT Posted July 7, 2007 Share Posted July 7, 2007 As long as you add gas and not liquid to the LP side you should be fine. Never used one of those small cans so not sure if they are labelled which way up. Double Award Winning Legacy GT Wagon Link to comment Share on other sites More sharing options...
pillboy Posted July 7, 2007 Share Posted July 7, 2007 Maybe yours is over-filled. I'm with mweiner on this one...pro with the proper equipment to test it. It is still ugly. Link to comment Share on other sites More sharing options...
f1anatic Posted July 7, 2007 Author Share Posted July 7, 2007 They are labeled for usage on the low pressure side. I am adding just the smallest size because there has been a slight decline in cooling power, outside temperature independent. Compared to last year. I have a digital thermometer that I used to measure temps at vents. I do not want to pay a pro 150 dollars to diagnose that I need a wee bit of charging. I just want to make sure the low pressure port is the one I "marked" in my picture. End of story. Link to comment Share on other sites More sharing options...
mwiener2 Posted July 8, 2007 Share Posted July 8, 2007 low refrigerant is not always the reason for decreased performance...which is why you need a pro to look at it. My Mods List (Updated 8/22/17) 2005 Outback FMT Running on Electrons Link to comment Share on other sites More sharing options...
mwiener2 Posted July 8, 2007 Share Posted July 8, 2007 and the outdoor temp at that time? My Mods List (Updated 8/22/17) 2005 Outback FMT Running on Electrons Link to comment Share on other sites More sharing options...
rao Posted July 8, 2007 Share Posted July 8, 2007 Get a pressure gauge and check it - it is not hard to do. Rob IF YOU CARE ABOUT YOUR CAR YOU SHOULD NEVER DRIVE IT Link to comment Share on other sites More sharing options...
bosco Posted July 9, 2007 Share Posted July 9, 2007 The ports are different sizes so that you don't mess up. The high pressure hose (which goes from the condenser) is smaller diameter and the low pressure hose (coming back from the evaporator) is larger). +1 and you are also correct on a pressure test w/gauge before you just add some refrigerant. you just keep adding refrigerant to the system and you will do some serious harm to compressor. bosco Stay Stock Stay Happy Link to comment Share on other sites More sharing options...
fweasel Posted July 9, 2007 Share Posted July 9, 2007 FWIW, the AC systems in both of my Legacys run about equal and are definately the most anemic coolers of any car that I've owned. ignore him, he'll go away. Link to comment Share on other sites More sharing options...
mwiener2 Posted July 9, 2007 Share Posted July 9, 2007 lately i've noticed that mine works better if i turn the temp UP It's been about 100 degrees on several day sover the last few weeks and at 73 degrees is just blew full blast constantly. Then I tried turnin gup to about 76, a more reasonable temp, and the blower was able to turn down and the recirc turn off. Design temp of an AC system is about 20 degrees below ambient. So if it's 95 degrees out, the inside temp won't go below 75. Try turning your temp UP and see what happens. My Mods List (Updated 8/22/17) 2005 Outback FMT Running on Electrons Link to comment Share on other sites More sharing options...
pillboy Posted July 9, 2007 Share Posted July 9, 2007 I never use the auto mode, always manual. Me too, I hate that effin fan running fill bore. Design temp of an AC system is about 20 degrees below ambient. Thanks. Useful info. Always wondered about the expected temp drop. It is still ugly. Link to comment Share on other sites More sharing options...
bosco Posted July 9, 2007 Share Posted July 9, 2007 lately i've noticed that mine works better if i turn the temp UP It's been about 100 degrees on several day sover the last few weeks and at 73 degrees is just blew full blast constantly. Then I tried turnin gup to about 76, a more reasonable temp, and the blower was able to turn down and the recirc turn off. Design temp of an AC system is about 20 degrees below ambient. So if it's 95 degrees out, the inside temp won't go below 75. Try turning your temp UP and see what happens. that might be b/c at the lower temp setting the fan is going full speed which doesn't give the coil enough time to cool properly there is such a thing as to much air flow. bosco Stay Stock Stay Happy Link to comment Share on other sites More sharing options...
f1anatic Posted July 9, 2007 Author Share Posted July 9, 2007 For reference, I sat in RC0032's car. At 73 F and level 3 fan speed I was freezing. In mine at 69 and level 3 it is acceptable. 90 degrees outside both times. Running on the highway as well. Recirculate. Link to comment Share on other sites More sharing options...
LIZARD Posted July 9, 2007 Share Posted July 9, 2007 I agree with most here, adding a "wee-bit" of refrigerant isn't the best thing to do. The AC system is "supposed" to be a closed sys. Buy a press. test kit first, determine if there's a leak, could just need a gasket. I too have recharged many different AC systems on many different cars, unfortunately never the LGT. I always do a pressure test first. Most GM's (I know, it's not a Chevy it's a Suby) the compressor gasket fails first. .02 Stage2.5376, TDC ProTune,blah blah blahhhh and....Alky/H20 injection Link to comment Share on other sites More sharing options...
LIZARD Posted July 9, 2007 Share Posted July 9, 2007 FWIW, setting the AC on auto is utterly useless. Stage2.5376, TDC ProTune,blah blah blahhhh and....Alky/H20 injection Link to comment Share on other sites More sharing options...
bosco Posted July 9, 2007 Share Posted July 9, 2007 this is the best way to charge any AC system, super heat. bosco http://www.contractingbusiness.com/25/ServiceClinic/Article/False/17963/ServiceClinic Stay Stock Stay Happy Link to comment Share on other sites More sharing options...
OBieXT Posted July 9, 2007 Share Posted July 9, 2007 Don't d*** around with that stuff. If you're going to do it, get yourself a set of gauges, high side and low side, and learn how to use them. There are resources on the web for that. Our systems only have a total capacity of 14-16 oz. If you dump a 4 oz can into there, you might by some rare alignment of the planets make things better. More likely you'll create a significant overcharge which will actually make your cooling worse (assuming of course it doesn't pop the relief valve which may fail to completely reseal and slowly bleed the system or that a slug of liquid refrigerant doesn't go through the compressor and pop the reed valves). Don't get me wrong, it's not rocket science, but you need to know what's going on in the system before just dumping more r134 into it. What you're proposing is akin to saying "I filled my car up last week and didn't drive it much but I'm leaving on a trip tomorrow and want to make sure I've got a full tank, so I'm going to dump this entire 4 gallon can into it." The miniscule capacity of our systems means that ANY leakage creates a serious undercharge situation. The flip side of that is that it won't take very much excess refrigerant to create a serious overcharge. Link to comment Share on other sites More sharing options...
LongHiway Posted July 9, 2007 Share Posted July 9, 2007 FWIW, setting the AC on auto is utterly useless. +1. My A/C works fine on manual. As BOSCO noted, I think higher fan speeds (like on Auto), push too much air across the coil. Try some experiments. Turn the A/C on in manual, leave the windows open (sunroof vented if you have one) for a few minutes. I think, this purges much of the hot air from the car simply sitting still. Leave the fan setting to 3, maybe 4. The close the windows. I end up turning the fan down to 1 or 2 even on hot days - just driving myself. More people in the car does add a bit more thermal mass. Link to comment Share on other sites More sharing options...
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