eseiler Posted April 27, 2006 Share Posted April 27, 2006 Hi...I'm back again. Hope you all have been doing well. I have a 96 OB and I was wondering if there were any special precautions I needed to take before attempting to recharge the A/C system. (I can't afford another trip to the ER). I bought 680 grams of 134a and I am concerned about possibly overfilling the system. Right now the A/C blows barely cool and the label under the hood above the radiator says 700-900 grams. Can anyone recommend the proper tool to refill the system? Thanks for your help. Damien Quote Link to comment Share on other sites More sharing options...
Subarian Posted April 27, 2006 Share Posted April 27, 2006 At the same place you bought your R-134a they should sell a filler hose with a guage. It indicates the pressure on the low side of the system. Just fill it according to the instructions that come with the guage, and you'll be fine. The other option is to evacuate the sytem and fill it with a known quantity of refrigerant. Quote Link to comment Share on other sites More sharing options...
nipper Posted April 27, 2006 Share Posted April 27, 2006 This can truly put you in the er if you do not know what you are doing. I am an epa certified a/c tech, if you dont know what your doing STOP and let a shop do it, its much cheaper then the ER bill. You need the proper gauges, and a vacume pump. You have to pull a vaaccum on the system to make sure all humidity is out, and you know that there is exactly zero refridgerant in the system. Evacuation of the system does two things, it creates a vacuum within the system for a full recharge and reduces the boiling point of water from 212 to around 70, nominal temps., making it possible to remove the moisture. SOme links http://experts.about.com/q/Auto-Air-Conditioning-1591/AC-Recharge.htm http://www.allpar.com/forums/index.php?showtopic=20709&st=80 http://autos.yahoo.com/maintain/repairqa/fluids_heat_air_conditioning_general/ques023_0.html Wear saftey glasses, wear saftey glasses, did i mention saftey glasses? nipper Quote Link to comment Share on other sites More sharing options...
Andyjo Posted April 27, 2006 Share Posted April 27, 2006 hey nipper, any reason my AC compressor doesn't kick on when i push the button? or.. the clutch doesn't even engage :-\ Quote Link to comment Share on other sites More sharing options...
nipper Posted April 27, 2006 Share Posted April 27, 2006 you have two pressure switches, a low pressure and high pressure. After checking fuses and rlays and such, i would bet your low on refridgerant. nipper Quote Link to comment Share on other sites More sharing options...
LosDiosDeVerde86 Posted April 27, 2006 Share Posted April 27, 2006 Hi...I'm back again. Hope you all have been doing well. I have a 96 OB and I was wondering if there were any special precautions I needed to take before attempting to recharge the A/C system. (I can't afford another trip to the ER). I bought 680 grams of 134a and I am concerned about possibly overfilling the system. Right now the A/C blows barely cool and the label under the hood above the radiator says 700-900 grams. Can anyone recommend the proper tool to refill the system? Thanks for your help. Damien you have to make sure you're putting it into the right hole. there's a high pressure and a low. you need to find out which one you need. i think it's the lower, but i'm not sure. Quote Link to comment Share on other sites More sharing options...
Andyjo Posted April 27, 2006 Share Posted April 27, 2006 you have two pressure switches, a low pressure and high pressure. After checking fuses and rlays and such, i would bet your low on refridgerant. nipper can't you bypass the pressure switch to see if the compressor works? Quote Link to comment Share on other sites More sharing options...
Subarian Posted April 27, 2006 Share Posted April 27, 2006 Sure, just jumper across the terminals on the plug. Quote Link to comment Share on other sites More sharing options...
Subarian Posted April 27, 2006 Share Posted April 27, 2006 you have to make sure you're putting it into the right hole. there's a high pressure and a low. you need to find out which one you need. i think it's the lower, but i'm not sure. You fill it on the low-pressure side. Your hose should only fit the low-pressure port. If you're not sure which is the low-pressure port, follow the line from the compressor back to the evaporator (the part inside the firewall) without going through the condensor (the part in front of the radiator). The low pressure port will be on that side of the compressor. The high-pressure side would likely blow up your refrigerant can, so you definitely don't want that one. Quote Link to comment Share on other sites More sharing options...
nipper Posted April 27, 2006 Share Posted April 27, 2006 Dont run the compressor too long. The refrigerant also lubricates the compressor, and thats not a cheap peice of metal to replace. nipper Quote Link to comment Share on other sites More sharing options...
tcspeer Posted April 27, 2006 Share Posted April 27, 2006 Nipper, on the 98 Wagon I bought the compressor wont come on unless I use a jumper wire from battery, then it runs fine. I checked the fuse and it looks good. Is their only one fuse? the one under the hood. If I remember right they are four relays do I need to change them all or is there a way to check them? you have two pressure switches, a low pressure and high pressure. After checking fuses and rlays and such, i would bet your low on refridgerant. nipper Quote Link to comment Share on other sites More sharing options...
nipper Posted April 27, 2006 Share Posted April 27, 2006 you have a relay that may be bad, its under the hood in the relay/fuse box on the drivers side. It is also possibble you have bad switches. If you have no pressure in the system its not going to run. Double checking the haynes book there is only one pressure switch (sorry) Take a metter to that switch, if its open, thats why the ac wont work, and it means that most likely there is no pressure in the system. This is where it gets hard to explain things over the net. Start with checking the pressure switch. Jump that switch and see if the AC come on normally. If it still doesnt come on, check the AC Relay. WHen you turn on the ac do the cooling fans come on too? With the compressor engaged (do not do this longer then a minute) check to see if the AC is blowing any cool/cold air. If not you have no freon or are low. There is a site glass, its on the pass side where the pressure switch is.Its on a black can behind the strut tower and near the ww motor. WIth the ac on there should be fluid in there 1/2 full (hard to explain). nipper Quote Link to comment Share on other sites More sharing options...
dmanaenk Posted April 27, 2006 Share Posted April 27, 2006 Ok, another AC question to nipper With engine warm or cold my compressor clutch engages for 10-30 seconds with 5-10 second breaks. Within 10 seconds after engaging AC blows real cold until disengagement. After that it's somewhat cold until next cycle. Pipe from the receiver/drier to evaporator is warm, from evaporator to compressor - fairly cold. Any idea on why it cycles on/off so often? Is the system overcharged/undercharged? I guess I'll go to autozone and borrow gauges to measure high/low pressure. Quote Link to comment Share on other sites More sharing options...
nipper Posted April 28, 2006 Share Posted April 28, 2006 Ok, another AC question to nipper With engine warm or cold my compressor clutch engages for 10-30 seconds with 5-10 second breaks. Within 10 seconds after engaging AC blows real cold until disengagement. After that it's somewhat cold until next cycle. Pipe from the receiver/drier to evaporator is warm, from evaporator to compressor - fairly cold. Any idea on why it cycles on/off so often? Is the system overcharged/undercharged? I guess I'll go to autozone and borrow gauges to measure high/low pressure. they all short cycle, thats normal. It saves gas as opposed to having the ac on all time.. System sounds fine. Gauges do you no good unless you know how to read them properly. Use a thermometer to determaine what the temp is of the air coming out of the ac vents. Depensgin upon your refridgerant 40-50F when it is 70 outside is fine, though 50 would have nme concerned with freon. Quote Link to comment Share on other sites More sharing options...
dmanaenk Posted April 28, 2006 Share Posted April 28, 2006 they all short cycle, thats normal. Well, Haynes manual says both pipes should be cold, that's why I got concerned. And in our other newer car AC compressor runs for a few minutes continuously when actively cooling (or with open doors), I though that was normal. Is subie AC system different? Quote Link to comment Share on other sites More sharing options...
nipper Posted April 28, 2006 Share Posted April 28, 2006 Well, Haynes manual says both pipes should be cold, that's why I got concerned. And in our other newer car AC compressor runs for a few minutes continuously when actively cooling (or with open doors), I though that was normal. Is subie AC system different? The 97 and 98 short cycled and blew cold air. When i had gauges on it it was fine. There must be an error in the haynes manual. Actually the hoses should be cold and colder, and it takes a few minutes for the lines to reach their true temperature. http://www.rationalautorepair.com/AC.html You cant really compare differnt makes of cars, as it depends upon the refridgerant too, the design of the system etc etc. nipper Quote Link to comment Share on other sites More sharing options...
dmanaenk Posted April 28, 2006 Share Posted April 28, 2006 Come to think of it - I see no way how condenser and receiver/drier would make refrigirant colder than ambient temp. So Haynes must be wrong there... Quote Link to comment Share on other sites More sharing options...
nipper Posted April 28, 2006 Share Posted April 28, 2006 Come to think of it - I see no way how condenser and receiver/drier would make refrigirant colder than ambient temp. So Haynes must be wrong there... one side can be frosty cold, and the other side cool, and depending where your grabbing hoses, the one side of the compressor is going to be hot, so be careful. WARNINIG .. thermodynamics lesson ahead http://www.chemistry.wustl.edu/~edudev/LabTutorials/Thermochem/Fridge.html nipper Quote Link to comment Share on other sites More sharing options...
dmanaenk Posted April 28, 2006 Share Posted April 28, 2006 Another question: on nasioc couple of people insulate couple of inches of refrigerant return line near firewall and near compressor. Does it really help? Seems like a good idea to me, but there might be smth I don't know rendering it useless/danegerous. Quote Link to comment Share on other sites More sharing options...
idosubaru Posted April 28, 2006 Share Posted April 28, 2006 STOP and let a shop do it, its much cheaper then the ER bill. depends how good your insurance is!! nipper being certified is the one you should listen to but i'll share my experience. buddy had a bad compressor in his honda that the shop wanted $1,300 to fix. i swapped in another one and i told him we needed to pull a vaccuum on it and i even have a vaccuum puller. he refused, he's impatient. he put about two cans of R134a in and the thing still blows colder than mine ever has to this day. can came with some cheap gauge and instructions on it. if i tried that mine would quit working in 4 months i know it!! $100 for parts and my free labor and he's been golden since. i've pulled vacuum and charged a/c myself. i'm not certified and i know little about refrigerant and stuff. i read up on the internet and got a set of gauges, vaccuum puller. (i'll admit i rarely use the gauges, boo for me) some subaru's (the XT6's for sure) have the glass you can look through. this isn't how you're "supposed" to do it, but it is a method that others have used and i have too without problem yet. again, it's not right, you're not supposed to, there's a "real" way...all that disclaimer stuff. Quote Link to comment Share on other sites More sharing options...
86subaru Posted April 28, 2006 Share Posted April 28, 2006 this might be be a dumb question but what name brand should i buy when doing it myself? + some of the cans says oil for your compresser , how often should oil be added ? Quote Link to comment Share on other sites More sharing options...
nipper Posted April 29, 2006 Share Posted April 29, 2006 And this is where you need a factory service manual. If i remeber correctly (somone correct me please) you dont need oil. Some compressors use oil in the freon to lubricate, other compressors are sealed and use internal lubrication (like a crankcase). Now IF you have the kind that circulates oil (i dont see an oil spec in the haynes manual so i am assuming subarus dont need it), the oil stays in as long as the AC is functioning. This is one of the reasons some older AC compressors will self destruct if they loose pressure and keep runing. There should be a label someplace on the ac compressor or under the hood stating how much refridgerant the system takes. If it needs oil, it will state how much there too. Refrigerant really only comes from one company, dupont, and is re packaged by different companies. Honeywell makes refrigerant too, but not for automotive use. Now do you have the right refrigerant for your car. Nothing personal but you are not giving me the warm fuzzies in the area of confidence that you know what your doing. i just don't want to see anyone hurt. nipper Quote Link to comment Share on other sites More sharing options...
jjou812 Posted April 29, 2006 Share Posted April 29, 2006 if you open a system (to change compressor for instance) air will get in. since air does not condense in the condenser you will get high head pressure. don't guess at this, have someone show you how it's done. also- if the comp cycles too frequently it's probably low on refrigerant and cycling the low pressure control. Quote Link to comment Share on other sites More sharing options...
nipper Posted April 29, 2006 Share Posted April 29, 2006 Short cycling is again one of those things that are hard to tell over the net. If in doubt, have it checked. This is really the one area of car repair that can seriously hurt you or worse, with the others being getting a hand or tie caught in the rotating parts, the radiator or blowing up the battery. nipper Quote Link to comment Share on other sites More sharing options...
86subaru Posted April 29, 2006 Share Posted April 29, 2006 i have recharged my own system a few times ,i bought a kit from a local auto store ,and followed all directions + asked a local shop , and the shop showed me the correct way to do it , no i do not do it for a living or even work on cars for a living , and yes it can be dangerous ,but if all directions are followed ,it's not that hard to do Quote Link to comment Share on other sites More sharing options...
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