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If you need a PT chart grab the Danfoss Refrigerant Slider I linked a few posts up. It's an app, has every refrigerant in it, and does Celsius/bar as well.
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Jun 12, 2017 23:04
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Motronic posted:Those are York compressors, and the only time you'll find one on a vehicle anymore is because someone is using it for onboard air to run tools and fill tires. I've got like 5 or 6 of these old York compressors from the Audis: 
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Jun 13, 2017 12:31
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monsterzero posted:Hmm. My high-side pressures we're in-range when the pump was on but my lows were low. Like 25psi instead of over 40psi. Should I add more refrigerant? I'll let Motronic confirm, but when charging my Subaru a few weeks ago after a condenser replacement, when my high side pressures were in spec my low side pressures were 5-10psi lower than the P/T chart. AC is ice cold though, so that's good enough for me. The compressor has almost 200k l presume, because I've never replaced it while I've owned the car. I didn't weigh the refrigerant going in, but the system calls for .88+/-0.07#, or 14-15.2oz. I put a 12oz can in, and enough from a second can to get the high side pressures in mid-spec, which wasn't much.
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Jun 13, 2017 15:53
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monsterzero posted:Hmm. My high-side pressures we're in-range when the pump was on but my lows were low. Like 25psi instead of over 40psi. Should I add more refrigerant? Sounds like lack of refrigerant + a restriction in the system. Did you replace the TXV or cap tube as well as the dryer? That's usually where you'll find restrictions. But in the end.....if it's working and holds like this I'd run with it. It doesn't need to be perfect if it's cold enough and you don't have pressures that are gonna blow up components.
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Jun 13, 2017 20:41
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Motronic posted:Sounds like lack of refrigerant + a restriction in the system. Did you replace the TXV or cap tube as well as the dryer? That's usually where you'll find restrictions. Didn't replace any parts, just added refrigerant. It's cold, and if it stays cold when it breaks 100 this weekend I'll call it good.
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Jun 13, 2017 21:31
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Boys who love boys
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What will make central air short cycle (like 2 minutes on, 5 minutes off) but only when it's above 90 or so? I cleaned the condenser and changed the air filter. Even after hosing it off for 10 minutes it wouldn't kick back on when I switched the thermostat back to cool. System is 4.5 months old. Already called the installer but they won't make it out tonight. Also, my tundra is the same as the Subaru. It doesn't seem to go above the mid 20's on the low side but cools ok. Just going to replace the leaking schrader and be done with it.
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Jun 15, 2017 02:54
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rdb posted:What will make central air short cycle (like 2 minutes on, 5 minutes off) but only when it's above 90 or so? I cleaned the condenser and changed the air filter. Even after hosing it off for 10 minutes it wouldn't kick back on when I switched the thermostat back to cool. System is 4.5 months old. Already called the installer but they won't make it out tonight. If it's short cycling it's going off on one of the pressure controls. Without having gauges on it, couldn't tell you which one. If it only happens when there's a high ambient though, it sounds like it might be either overcharged, or have some airflow issue with the condenser. Though if it's only 4 months old it shouldn't be that dirty.
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Jun 15, 2017 03:32
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ExplodingSims posted:Without having gauges on it, couldn't tell you This. Covered in the OP, bur maybe I need to make it more obvious that AC problems typically can't be divined out of symptoms.
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Jun 15, 2017 03:37
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It's in warranty, I don't think I should put my gauges on it. Cars and my old lovely one, no problem. Hopefully the tech does tomorrow or whenever they come out. Just want to know for sure what they should be looking for or what I could do in the mean time. I did hose off the outdoor unit this afternoon, and changed the filter so it's getting decent airflow. The evaporator coil doesn't appear to be dirty. Would a compressor blanket cause this? Is there a thermal cutout on a Copeland scroll compressor and how do you check that? rdb fucked around with this message at 04:15 on Jun 15, 2017 |
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Jun 15, 2017 04:12
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As a follow up, the company stopped by today and removed some refrigerant although it did not appear to be that far off. The engineer said the unit called for 10 degrees subcooling and left it at 9.3. I asked if the blanket was the cause and he didn't think so. Either way it's supposed to be 93F/sunny with a dew point in the 70s tomorrow. If it fucks up again they will come back out.
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Jun 15, 2017 21:06
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When you say blanket, you're talking about the noise insulator jacket that goes around the compressor? That would not cause it to overheat. The compressor itself is not cooled by air, it's cooled by the refrigerant coming back into it.
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Jun 15, 2017 22:29
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If I have a vehicle with just a few PSI in the AC system (obviously leaks somewhere), am I safe to just change all the under hood o-rings, dryer, vac the system and charge it assuming it holds vacuum? If the r134a just leaked out slowly, I shouldn't have to bother adding oil, right? Also assuming the system is clean, not full of black poo poo, etc, etc.
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Jun 18, 2017 01:54
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Yeah, there's oil in the refrigerant, so as long as you're not changing the comp you'll be fine.
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Jun 18, 2017 02:42
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I'm gonna assume the compressor is fine, I don't have reason to suspect it's bad, nor do I feel like changing it. It's my dad's truck and I'm tired of him complaining the AC doesn't work every time I talk to him in the summer.... (and hey, it's father's day tomorrow) I know some oil accumulates in the dryer, should I add a few grams to replace it?
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Jun 18, 2017 02:57
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I wouldn't really worry about it. Like I said, there's oil in the refrigerant.
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Jun 18, 2017 04:49
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How old is the truck? Refrigerant slowly diffuses through barrier hoses over time. It's possible the rest of your system is fine and just needs a recharge. Wouldn't hurt to put in one can that has dye mixed in though, just in case. E: Also I could be mistaken, but if you've got some positive pressure, there shouldn't be any moisture in the lines and you can leave the dryer alone.
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Jun 18, 2017 06:34
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Enourmo posted:How old is the truck? Refrigerant slowly diffuses through barrier hoses over time. It's possible the rest of your system is fine and just needs a recharge. Wouldn't hurt to put in one can that has dye mixed in though, just in case. It's a 2005, so likely the system has never been touched. I realize that refrigerant leaks out over time, but it seems really stupid not to change all the o-rings and dryer while the system is drained. If you gonna do it, do it right. And yea, I'd definitely put dye in to help find future problems. ExplodingSims posted:I wouldn't really worry about it. Like I said, there's oil in the refrigerant. Only if I buy a can of refrigerant that has oil in it... chrisgt fucked around with this message at 12:12 on Jun 18, 2017 |
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Jun 18, 2017 12:08
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All refrigerant has oil mixed in with it. You can get specialty cans that have a bit extra in them, but otherwise there is already oil mixed into a regular can.
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Jun 18, 2017 14:40
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For some reason just had an idea about cleaning the condenser having an effect on the AC efficiency and watched an ETCG video where it lowered high PSI by 60. Anyone done this? I'm going to have the front bumper off anyway so am thinking that I might as well do it.
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Jun 18, 2017 14:52
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Oh yeah, a dirty condenser will absolutely effect efficiency. Airflow is very important to the cycle, so it's a good idea to hose it out even once in a while. Luckily, car condensers don't get anywhere near as dirty or impacted as normal A/Cs can. You'd be surprised just how much dirt can get crammed in between fins. In fact, that's what kills compressors more than anything, lack of airflow.
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Jun 18, 2017 15:06
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ExplodingSims posted:All refrigerant has oil mixed in with it. You can get specialty cans that have a bit extra in them, but otherwise there is already oil mixed into a regular can. I'm not sure where you're getting your refrigerant, but that's just not the case for me, even in small cans. I've done enough stupids with can taps coming loose/bleeding out the last of a can (totally by accident!) that I would know for drat sure if there was oil in those cans.
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Jun 18, 2017 15:37
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ExplodingSims posted:Oh yeah, a dirty condenser will absolutely effect efficiency. Airflow is very important to the cycle, so it's a good idea to hose it out even once in a while. Cool, I'll be cleaning / straightening my condenser then.
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Jun 18, 2017 16:17
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MrOnBicycle posted:Cool, I'll be cleaning / straightening my condenser then. FYI: https://www.amazon.com/ABN-Condense...rator+Coil+Rake Will make your life a lit easier.
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Jun 18, 2017 16:28
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Motronic posted:I'm not sure where you're getting your refrigerant, but that's just not the case for me, even in small cans. Do they use a different blend of 134a for automotive use then? Because all the 30lb cylinders of refrigerant we use at work all come with oil mixed in. Motronic posted:FYI: https://www.amazon.com/ABN-Condense...rator+Coil+Rake Just be careful if you intend to use this on your car's condenser, as those are usually microchannel condensers, and don't have traditional vertical fins.
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Jun 18, 2017 16:38
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I've never heard of oil in refrigerant cylinders either. It would be kind of stupid because you don't want to mix oil types and what oil is in it? Never had to order a cylinder of refrigerant by oil type
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Jun 18, 2017 17:03
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I guess I was wrong. I had always heard that there was generally a little bit of oil mixed in with them but I guess about spending in a sentence. Or I had some wires crossed in my brain, I guess working 80 hours a week will do that to you.
ExplodingSims fucked around with this message at 17:29 on Jun 18, 2017 |
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Jun 18, 2017 17:27
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The cans you buy with leak sealer in them will generally have some pag100 oil in it to replace what may have been lost to a leak. That may be what you were thinking of.
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Jun 18, 2017 21:24
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I was confused by oil in refrigerant, too... I generally only see cans come with oil when it's a "DIY fix your AC by adding this stuff without knowing what you're doing" kit that tend to cause more problems than they solve. I fell victim to that in my infancy of working on cars, it was the most effective way of turning an otherwise good compressor into a pile of parts on the road, literally. 10 years later I've recovered from my stupid mistake and finally bought all the tools to do AC somewhat properly without blowing poo poo up, two of my trash heaps now have working AC, it's nice.
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Jun 19, 2017 02:27
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So I've got a bad head gasket on my freshly recharged Subaru. I'll need to disconnect the AC lines to pull the motor. Do shops take walk-ins who want their systems evacuated an refrigerant collected? I don't want to vent it because I already feel guilty about loving the atmosphere with my 2smokes. I'll need to replace the filter/dryer and seals when I put it all back together. Will I need to replace anything else, like the expansion valve?
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Jun 22, 2017 18:06
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I've never had to open the system to pull the motor on a Subaru. Just unbolt the compressor first and push it out of the way. You'll have to be careful about the condenser, I normally use a piece of 1/4" plywood that covers most of the rear face to protect from accidental bumps.
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Jun 22, 2017 21:56
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PitViper posted:I've never had to open the system to pull the motor on a Subaru. Just unbolt the compressor first and push it out of the way. That's promising. It's a 3.0L 2nd-gen Outback and the factory service manual recommends opening the system. I'll try to take a hard look at it and see if I'll be able to move the compressor and lines enough. Just sucks because it will be infinitely more difficult to responsibly evacuate the system once I start the pull.
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Jun 22, 2017 21:59
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I've only ever had to pull the 2.5s for head gaskets, but I imagine like all the other Subaru Lego cars, it's probably the same compressor and lines. I believe I just pulled the compressor and lines off to the driver side, but it's been a while.
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Jun 23, 2017 05:12
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A buddy of mine has a ~2010 Acura TSX with weak AC. I told him to bring it it my place so we can check it out. I've got gauges, plenty of 134a, and this thread. He said no, that he's seen on the forums that TSXs do better with a full evac and recharge. It's not my money or time, so I didn't argue the point, but is there any truth in it?
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Jun 23, 2017 11:05
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EVERYWHERE 
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Welp, the Audi 90 has an AC leak somewhere, it'll hold a good charge for about two months before the compressor starts short-cycling. Probably just need to do the seals all around and the drier. Had to dump a can of PC Duster (8 oz) in it this morning to get it working again. Question though: Is it common, with a slow leak, for the oil to leak out as well? Need to figure out if I need to go pick up a can of ester oil. CommieGIR fucked around with this message at 11:48 on Jun 23, 2017 |
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Jun 23, 2017 11:40
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Seminal Flu posted:A buddy of mine has a ~2010 Acura TSX with weak AC. I told him to bring it it my place so we can check it out. I've got gauges, plenty of 134a, and this thread. He said no, that he's seen on the forums that TSXs do better with a full evac and recharge. The only way I treat my cars is with full evac and recharge. I dealt with mini splits for work mostly and that's the only way to do them right as well. Weigh what you take out. If low - there's a leak and no point vaccing out until you deal with it. If the charge you pull out is correct, well then you know you have a blockage or some other mechanical problem maybe - deal with that before throwing in new refrigerant (E: or maybe even airflow problem evap or condenser - in car filter/dirty fan, collapsed ducting or condenser fan cutting out etc). If over, then someone reading threads like these charged by pressure. Could be overcharged due to an underlying partial restriction that just got worse. You can't charge by pressure, you can't know operating pressures etc if you don't know the design spec. Reading a gauge can tell you if something is seriously wrong, but 100kpa or more off where you think it should be could mean nothing so it's bad when someone charges by their ideal pressures. Pressures to an exact number range only mean something when you know and can measure design temps as well. I didn't work on cars much, but in refrig there's a whole lot of difference between large evap and low td/high humid fruit and veg coolers compared to high TD low humidity beverage coolers with smaller evaps. What pressures you get depends on evap size, TEV/oriface and of course car air cons and not designed or charged to work or show design pressures while at stand still with no real air flow, and you can't look at gauges and charge while driving down the highway exactly (not a challenge). Reclaim and weigh (and check charge to give clues as above), evac and charge by weight. Fo3 fucked around with this message at 12:07 on Jun 23, 2017 |
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Jun 23, 2017 11:43
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CommieGIR posted:Welp, the Audi 90 has an AC leak somewhere, it'll hold a good charge for about two months before the compressor starts short-cycling. Probably just need to do the seals all around and the drier. You're mixing two types of refrigerant in the same system? STOP IMMEDIATELY DO NOT USE THE AC. The 152a won't carry anything other than ester oil, and as such you're going to destroy the compressor. You need to evac the system, completely flush it, fix the leaks, and start over. Seriously, stop using the AC.
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Jun 23, 2017 12:05
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chrisgt posted:You're mixing two types of refrigerant in the same system? STOP IMMEDIATELY DO NOT USE THE AC. The 152a won't carry anything other than ester oil, and as such you're going to destroy the compressor. You need to evac the system, completely flush it, fix the leaks, and start over. Seriously, stop using the AC. No, it only has R152a. I'm not new to this. R152a is the only thing I use, and I've disassembled and reassembled this AC system twice. Please see previous AC threads, its not my first AC thread, nor my first time rebuilding and maintaining automotive AC systems. CommieGIR fucked around with this message at 12:28 on Jun 23, 2017 |
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Jun 23, 2017 12:26
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While replacing the front suspension on my wife's 1991 Tracker my hand slipped and the wrench tapped the top of the compressor. There was a 'SSSSSSSSSSSSSSSSSSSssssssss" that slowed down then stopped after probably 30~ seconds or so. I haven't done any leak testing yet but I'm confident the one I caused it the metal piping on the very top of the compressor where the two lines go in. We bought this Tracker about 4 months ago and the compressor would kick on when you'd flip the AC but it blew warm. Now that I know it was under pressure and I vented it to the atmosphere I suspect that it had just slowly leaked out the R12 since I doubt the system has been charged since 1991. The vehicle was a snowbird's winter car so was always driven with the top down. My questions: I need to replace the filter inside my drier core (according to my official service manual) for one since I vented, but should I convert the system? R-12 isn't impossible to get and this Tracker has all of 90hp to begin with and I'd rather not lose any sort of cooling performance out of it. It's also a convertible so it will be losing cool are in the cabin from that. My wife loves it so she'd like to start driving it all the time which means cruising around in 98 F weather with close to 100% humidity. I also have a 1990 Honda Acty with AC that works great once I had it charged with R12, and that thing has maybe 40 hp.
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Jul 3, 2017 18:45
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So I had a mechanic check my system and the compressor works fine, and barring a pressure sensor not working its likely the problem is low pressure. I also know there's some pressure in the lines, so hopefully just needs some more coolant. Instead of paying $2-300 for a mechanic is there any reason not to buy a canister of coolant and feed it in a little at a time until the clutch kicks in?
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Jul 3, 2017 19:30
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Seminal Flu posted:A buddy of mine has a ~2010 Acura TSX with weak AC. I told him to bring it it my place so we can check it out. I've got gauges, plenty of 134a, and this thread. He said no, that he's seen on the forums that TSXs do better with a full evac and recharge. Fo3 posted:The only way I treat my cars is with full evac and recharge. I dealt with mini splits for work mostly and that's the only way to do them right as well. To follow-up on this, he took it to a place that diagnosed a valve that needed to be tightened. They topped the refrigerant, and he's good. Sometimes you get lucky.
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Jul 3, 2017 19:31
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