1 Lucky Texan Posted September 25, 2015 Share Posted September 25, 2015 either way, be prepared with a vacuum hose attachment to clean around in there. Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted September 26, 2015 Share Posted September 26, 2015 I've replaced quite a few cabin air filters lately. Most manufacturers recommend replacing them every 6 months to 1 year. I don't even know how many I've replaced that looked like they are the original filter from 5, 6, 10 years old, and they are absolutely filthy. One had about 3" of leaves and pine needles sitting on top of it. If you're having trouble with the drain, more than likely the filter is gone or has deteriorated and fallen apart and a bunch of crud has fallen into the evaporator housing. Quote Link to comment Share on other sites More sharing options...
stackman1 Posted September 27, 2015 Author Share Posted September 27, 2015 I've replaced quite a few cabin air filters lately. Most manufacturers recommend replacing them every 6 months to 1 year. I don't even know how many I've replaced that looked like they are the original filter from 5, 6, 10 years old, and they are absolutely filthy. One had about 3" of leaves and pine needles sitting on top of it. If you're having trouble with the drain, more than likely the filter is gone or has deteriorated and fallen apart and a bunch of crud has fallen into the evaporator housing. Bingo! They never put a filter in......of course this is the first time I went to replace it but still!!!! The blower is running fine and sucking in outside air (no filter) so the problem lays between the blower and the dash vents. But if it runs fine initially and then quits blowing hard - is it an icing issue in the evaporator? I actually changed the expansion valve myself two years ago. But don't remember much about it. Something I can tackle? Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted September 28, 2015 Share Posted September 28, 2015 See if the same happens when the AC is not running. The evaporator shouldn't ice over, because it's supposed to have a temperature sensor stuck in the middle of the core somewhere that shuts the compressor off if the core gets too cold. Quote Link to comment Share on other sites More sharing options...
stackman1 Posted September 28, 2015 Author Share Posted September 28, 2015 See if the same happens when the AC is not running. The evaporator shouldn't ice over, because it's supposed to have a temperature sensor stuck in the middle of the core somewhere that shuts the compressor off if the core gets too cold. You mean - see if the vent stops pushing air after awhile - without turning the a/c on? Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted September 28, 2015 Share Posted September 28, 2015 Yep. Quote Link to comment Share on other sites More sharing options...
stackman1 Posted October 10, 2015 Author Share Posted October 10, 2015 You mean - see if the vent stops pushing air after awhile - without turning the a/c on? Seems like the blower keeps pushing air through the vents when a/c isn't on....... And from what I can tell, the dripping on the passenger foot well emanates from where the black drain hose is attached to the what I assume must be the evaporator (the same black hose that runs through the firewall that I blew out). It begins just under (but not to) the large white plastic cover the hides the expansion valve. Should I pull off black hose and see if crud comes out? Also, am I correct in assuming that if the evaporator did ice over - the air flow would be diminished - even at the same blower speed? Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted October 10, 2015 Share Posted October 10, 2015 If its dripping from the hose, there could be a blockage in the hose, or it may just need a small clamp or zip-tie around it to tighten it up against the nipple. Make sure the water isn't running down from another seam or a crack on the box. Yes, if the core ices, the ice will block airflow. If the core is icing, either the evaporator thermal sensor isn't working correctly, or it has fallen out of the core and can't accurately read the core temperature. Quote Link to comment Share on other sites More sharing options...
stackman1 Posted October 11, 2015 Author Share Posted October 11, 2015 If its dripping from the hose, there could be a blockage in the hose, or it may just need a small clamp or zip-tie around it to tighten it up against the nipple. Make sure the water isn't running down from another seam or a crack on the box. Yes, if the core ices, the ice will block airflow. If the core is icing, either the evaporator thermal sensor isn't working correctly, or it has fallen out of the core and can't accurately read the core temperature. Good suggestions about tightening the hose connection. So based on the fact that when I run the a/c for a longer period and the airflow diminishes - is the only likely explanation that - the core is freezing? Assuming that is the case. Do you know if I can get at the evaporator core and replace the thermal sensor? Ever heard anyone doing it without totally dismantling the dashboard? Thanks for your feedback. Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted October 11, 2015 Share Posted October 11, 2015 I'm not familiar enough with the setup on that model to say exactly how difficult it is to replace. If it's like the 95-2000 models the blower box has to be removed, which requires removal of thee entire dash. The first thing to do is try to confirm that the core is freezing, which you may be able to do by looking in through the opening for the blower motor. You would have to run the AC until the problem starts, then quickly remove the blower motor and probably use a small mirror to see inside. Quote Link to comment Share on other sites More sharing options...
stackman1 Posted October 30, 2015 Author Share Posted October 30, 2015 If its dripping from the hose, there could be a blockage in the hose, or it may just need a small clamp or zip-tie around it to tighten it up against the nipple. Make sure the water isn't running down from another seam or a crack on the box. Yes, if the core ices, the ice will block airflow. If the core is icing, either the evaporator thermal sensor isn't working correctly, or it has fallen out of the core and can't accurately read the core temperature. I had the a/c on today and it wasn't very cold but I ran it and then checked the passenger foot well for dripping. It is actually leaking along the bottom of the plastic seal on white evaporator cover. Quote Link to comment Share on other sites More sharing options...
stackman1 Posted October 30, 2015 Author Share Posted October 30, 2015 (edited) I decided to see if I could get to the thermo sensor on the evap core. I got to where I could see it. So I disconnected the lines through the firewall that attached to one side of the expansion valve (system had been evacuated). But can't seem to figure out how to disconnect expansion valve. I had actually replaced this expansion valve a couple of years ago but my memory is bad. Here is my question: Having disconnected the lines through the firewall shouldn't I be able to pull the expansion valve and attached lines away from the firewall? It won't budge. Even if I could reach those two nuts/bolts between the lines - I don't know what tool to use on them.....they are tiny threaded bolts - not hex bolts. Jeez Ideas? Edited October 30, 2015 by stackman1 Quote Link to comment Share on other sites More sharing options...
stackman1 Posted October 31, 2015 Author Share Posted October 31, 2015 Well...after moving the air filter out of the way - I could see I needed to unscrew the hex nuts on the engine side in order to free the expansion valve inside. Don't remember doing any of that before. I am getting old. So I kept going and with some scraped knuckles got managed to pull th evap core out. The thermo sensor was inserted into the lower driver side corner of the fins. It looked ok. But there was a fair amount of crushed leaves on the the bottom inch of the the evap core. So I vacuumed and then hosed it a bit. Cleaned out the evap core holder and reinserted it. Putting expansion valve back into position was a bitch because I forgot about the positioning of the rubber gasket holder in the fire wall and lining everything up was hard with one guy. But I reconnected everything . Who knows if I caused more problems doing this or not. Didn't have Pag Oil to lubricate the o-rings but things looked ok? So I spent a day basically just to get some crud off the bottom of my evap core. Hopefully cleaning the evap core will stop my dripping/icing.....not absolutely sure it is icing but sure as hell was dripping. Drain hose from base of evap through firewall - totally clean. So since the winter is coming here in NY and the system is empty of R134 what should I do? Will it hurt the system to go through the winter without R134. Will it dry out rings? Should I put a vac on it and get rid of moisture? Add Pag Oil - if so where? I am counting on a/c next summer again for Florida - try to keep my 14 yo Subie cool. Any thoughts welcome. Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted October 31, 2015 Share Posted October 31, 2015 Man you got it all backwards! You're supposed to go to Florida for the winter, New York for the summer! You should vacuum it and charge it up. Even if you don't use it, you don't want air in the system all winter because the moisture in the air can corrode parts inside. Quote Link to comment Share on other sites More sharing options...
stackman1 Posted November 1, 2015 Author Share Posted November 1, 2015 Man you got it all backwards! You're supposed to go to Florida for the winter, New York for the summer! You should vacuum it and charge it up. Even if you don't use it, you don't want air in the system all winter because the moisture in the air can corrode parts inside. Wow - that got a laugh this morning. Unfortunately - appropriate to your handle - since I own an old home near the beach - I have to move out during the summer months to just cover the property taxes! Thanks for the input on the car as usual...I kind of felt that was the right thing to do. Any thoughts on adding Pag OIl - I see people talk about. If so, where would I add it and how much? Thanks man. Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted November 1, 2015 Share Posted November 1, 2015 Normally you only add oil if you replaced a part that holds a fair amount of it, such as the evaporator, condenser, drier, or the compressor. If you didn't remove or drain any oil from those parts, there's no need to add. Quote Link to comment Share on other sites More sharing options...
stackman1 Posted November 4, 2015 Author Share Posted November 4, 2015 Well.....I bought 19oz of R134a. Put my vacuum on for 45 minutes and got a solid vacuum. However when I turned the vacuum off and had gauge valves close. It didn't hold the 29hg mercury like it has in the past. Probably dropped to 15hg. Anyway. I decided to vac it again and then quickly recharged hoping that there might be sealant in the refrigerant. Drove it around and it was freezing. But after about 5 minutes..... not so much. Popped the hood and look at the white-out on my pipes! Quote Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted November 4, 2015 Share Posted November 4, 2015 if you haven't, change the o-rings at the suction and discharge hoses on the compressor - they almost turn to plastic with heat and age. had to do that on my wife's 03 OBW. Quote Link to comment Share on other sites More sharing options...
stackman1 Posted November 4, 2015 Author Share Posted November 4, 2015 Now - not completely surprised it didn't hold a great vacuum because frankly I was pretty aggressive over the weekend. I got to the Evap Core because I felt that maybe it could tell me more about the both the dripping in the footwell as well as the reduced airflow after running the a/c for awhile. I had it in my mind that the evap core was freezing up. So I essentially dismantled everything a/c related from the firewall in the cabin. I disconnected the evap core. It had crud on lower inch. Checked thermo-sensor for any visible damage. Didn't see any. I didn't change the expansion valve which I should have but had my fingers crossed. Putting everything back was a bitch. Got the evap core back in after cleaning - tried not to crush thermo-sensor? Then reconnected the evap core lines to the old Expansion Valve and then tightened the expansion valve by tightening the hex and bolt on the spacer from engine side of firewall. So like I said it was really cold and then I popped the hood. Quote Link to comment Share on other sites More sharing options...
stackman1 Posted November 4, 2015 Author Share Posted November 4, 2015 It would appear that the expansion valve is likely operating - since I understand it is the part that makes the refrigerant turn cold? Is the evap core maybe not receiving the refrigerant - might that explain the frosted pipes? Tex - When I had system evacuated I looked at the o-rings on the compressor - low and high - they seemed ok. Would that explain the frosted lines? Any thoughts appreciated. Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted November 5, 2015 Share Posted November 5, 2015 In the whole time the AC was running before you noticed the lines were frosted, did you ever hear the compressor cycle off? Quote Link to comment Share on other sites More sharing options...
stackman1 Posted November 5, 2015 Author Share Posted November 5, 2015 In the whole time the AC was running before you noticed the lines were frosted, did you ever hear the compressor cycle off? No Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted November 5, 2015 Share Posted November 5, 2015 That, I'm about 95% positive, means the thermal switch on the evaporator is bad. It's not telling the ECU to turn the compressor off when the core temperature drops to 32°F. It could also be due to a faulty expansion valve, but even if the valve is bad, the thermal switch should still be turning the compressor off when the core gets too cold. Quote Link to comment Share on other sites More sharing options...
stackman1 Posted November 5, 2015 Author Share Posted November 5, 2015 That, I'm about 95% positive, means the thermal switch on the evaporator is bad. It's not telling the ECU to turn the compressor off when the core temperature drops to 32°F. It could also be due to a faulty expansion valve, but even if the valve is bad, the thermal switch should still be turning the compressor off when the core gets too cold. I assume by the thermal switch you mean the sensor with a wire that is inserted into the fins of the evap core? If I recall Subaru wants some absurd price....I was stupid. I should have replaced the expansion valve when I had the damn thing disassembled. Last time I used an after market Expansion Valve from RockAuto - Subaru wanted $90 - Rockauto charged me $18. It seemed to work fine. I should have ordered another one before I re-charged and put it in. Quote Link to comment Share on other sites More sharing options...
stackman1 Posted November 5, 2015 Author Share Posted November 5, 2015 Well - Just got off the phone with the local Subaru Dealer. They would have to order it. It is called a "thermistor". It is $75 - less than I thought they would charge. If I bite the bullet and order it would you suggest paying the $89 for the Subaru Expansion Valve or just using Rock Auto again for $17? Anything else I should get if I move forward? Thanks FairTax Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.