Need some AC advice/help EXP VALVE FIXED!!!!!!
Printed From: TheAMCForum.com
Category: The Garage
Forum Name: HVAC
Forum Description: air conditioning, heater and associated controls
URL: https://theamcforum.com/forum/forum_posts.asp?TID=105494
Printed Date: Apr/23/2024 at 7:51pm
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Topic: Need some AC advice/help EXP VALVE FIXED!!!!!!
Posted By: Texas275
Subject: Need some AC advice/help EXP VALVE FIXED!!!!!!
Date Posted: May/05/2020 at 8:31pm
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In need some help with my add on AC/Heat. I picked up a working used Sanden Compressor, used clean condenser, new dryer, new hoses, new evaporator/heat unit. Since the compressor was used I drained and refilled the oil according to Sanden specs. Everything connected and working, but I cant get it to cool to any lower than 60 degrees at the vent. Heat not on. I found no leaks, it held a vacuum for 3 weeks before I charged it. No noise from the compressor, engages fine when powered on and spins like it should. When I hook up the gauges and I get 80 psi static on both gauges at 80 degree ambient temp. When its running, on high, the Low Side gauge is at 95 psi, and the High Side is at 90 psi. Looking at the sight glass on the gauges it looks pretty frothy, like its got a lot of air in the system. According to the charts the Low should be 40-50 psi and the High should be 175-210 psi. So what am I missing? I don't have a problem evacuating and recharging, If I need to replace something I can do that, I'm just kind of stuck as to my next step.  Any help would be greatly appreciated, Tom
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Replies:
Posted By: Heavy 488
Date Posted: May/05/2020 at 8:49pm
| Expansion valve? |
Posted By: Texas275
Date Posted: May/05/2020 at 9:33pm
| Its is new with the evap/heater. Is there a way to test it, before I just buy one and put it on? |
Posted By: Heavy 488
Date Posted: May/05/2020 at 9:59pm
an actual method to test I don't know. you don't really have much of any pressure differential which to me says it doesn't work. https://duckduckgo.com/?q=auto+ac+diagram&t=fpas&iax=images&ia=images&iai=https%3A%2F%2Fwww.fixmyoldride.com%2Fimages%2FAuto-AC-diagram.jpg" rel="nofollow - https://duckduckgo.com/?q=auto+ac+diagram&t=fpas&iax=images&ia=images&iai=https%3A%2F%2Fwww.fixmyoldride.com%2Fimages%2FAuto-AC-diagram.jpg
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Texas275 wrote:Posted By: Texas275
Date Posted: May/05/2020 at 10:39pm
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Sounds like a plan. They are cheap and easy to get to. I'll see if I can pick one up locally tomorrow. If not, I'm sure amazon has one. Thanks for the jumping off point. Tom
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Posted By: motorhead_1
Date Posted: May/05/2020 at 11:04pm
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wrong expansion valve. R12 and 134 should be different as the freon molecules are different sizes. will they interchange, sure, but won't be as effective. i think your problem lies elsewhere. compressor valves likely ------------- 69 SC/Rambler tribute 401/th400, 68 Rebel SST LSA, 66 F100 460/c6, 88 Merkur Xr4Ti, 71 Jaguar XJ6 LS1, 08 Supercharged Tundra |
Posted By: 6768rogues
Date Posted: May/05/2020 at 11:11pm
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I suspect the used compressor. You have neither suction nor pressure. Is it R134A? If so, ignore the sight glass, it only works with R12. I don’t think it is your problem but did you charge into the vacuum? When it is working the high side should not be over twice ambient plus 80 degrees. ------------- Content intended for mature audiences. If you experience nausea or diarrhea, stop reading and seek medical attention. Located usually near Rochester, NY and sometimes central FL. |
Posted By: Texas275
Date Posted: May/06/2020 at 9:08am
| It is a 134 evap system so I figure it is a 134 expansion valve. When I charged it initially it held vacuum for 3 three weeks before charging. I charged it with the vacuum pulled. It took it a while but it pulled all the 134 in. That was about a month ago. It was down into the 40 degree range at the vent. But now it won’t get any lower than 60 at the vent. |
Posted By: Heavy 488
Date Posted: May/06/2020 at 9:30am
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what's the temp coming into the evaporator? |
Posted By: Mopar_guy
Date Posted: May/06/2020 at 11:22am
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Is the rest of the system stock or aftermarket? The problem is withe the pressure differential - there's not enough of it. Expansion valve is the #1 suspect.
-------------  " http://theamcforum.com/forum/hemilina_topic95889.html" rel="nofollow - Hemilina " My 1973, 5.7 Hemi swapped Javelin |
Posted By: Texas275
Date Posted: May/06/2020 at 12:53pm
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I don't know the temp going in; I'll have to check it when I get home. No OEM parts, everything is aftermarket.
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Posted By: mstrcrftr
Date Posted: May/06/2020 at 1:31pm
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its the compressor.. no pressure coming out means no suction in.. |
Posted By: Texas275
Date Posted: May/06/2020 at 6:00pm
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Today static right at 90 ambient temp 90 Both high and low at 90 psi when running. Used laser thermometer on metal hose going in 70 deg Vent 60 degrees. Doesn’t look like much movement of the Freon. Does that point at compressor? |
Posted By: Heavy 488
Date Posted: May/06/2020 at 6:11pm
| Close the suction valve and see if it climbs. |
Posted By: Texas275
Date Posted: May/06/2020 at 6:58pm
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Both high and low side at 100 Close low side gauge it drops to 35 high goes up to 150
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Posted By: Heavy 488
Date Posted: May/06/2020 at 9:32pm
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so the compressor went to 150. this should rule out the compressors inability to pump up. this still takes me back to the expansion valves inability to throttle.
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Posted By: Texas275
Date Posted: May/06/2020 at 9:57pm
| Ok, I'm gonna start with an expansion valve. If I'm going to throw a part at it; it's best to start with the cheaper part. |
Posted By: tomj
Date Posted: May/06/2020 at 11:30pm
I was thinking the same thing. A better measure of A/C is temperature drop, inlet to outlet. A temperature drop (difference) of 40 degrees F is good I think. But sounds like something else is wrong. ------------- 1960 Rambler Super two-door wagon, OHV auto 1961 Roadster American, 195.6 OHV, T5 http://www.ramblerLore.com |
Posted By: 401MATCOUPE
Date Posted: May/07/2020 at 5:19am
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If you are getting to no delta temp drop and pressures stay near equal....that usually means the compressor has failed internally, Sanden's have known issues with that.....another clue if the suction side is not low (30-45 psi) when running and high side is not up.....expansion valves do not like any debris in system.....and they do fail, both wide open and closed. ------------- Ross K. Peterson 68X,GoPac,343,AT,52A(1stCar) 68X,GoPac,390,4sp,52A 69X,GoPac,390,4sp,64A 70X,GoPac,390,4sp,87A,8 70X,GoPac,390,4sp,BBO,8 70 Jav SST,390,AT,BSO 74MatX,401,AT,Prototype 74MatX,401,AT |
Posted By: Texas275
Date Posted: May/07/2020 at 11:36am
| I think my best course is to start with the expansion valve. If it's not that, I'll get me another compressor. |
Posted By: Heavy 488
Date Posted: May/07/2020 at 12:44pm
| You already saw the compressor able to hit 150 with the suction closed. what target number were you shooting for that needs another compressor? |
Posted By: Texas275
Date Posted: May/07/2020 at 12:48pm
| I agree with you. That's why I'm replacing the valve. |
Posted By: george w
Date Posted: May/07/2020 at 12:54pm
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Sure sounds like the expansion valve is stuck open. The system depends on that restriction to develop the pressure differential. ------------- Long time AMC fan. Ambassador 343, AMX 390, Hornet 360, Spirit 304 and Javelin 390. All but javelin bought new. |
Posted By: Texas275
Date Posted: May/07/2020 at 4:05pm
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So I came up with a question as I was pulling the expansion valve off. Does the expansion valve have to be oriented in any particular position. Mine is in upside down, silver flat disc down. That’s how I had to place the evaporator behind the dash. Would that keep it from working properly? If it has to be turned over, can I add a U shaped line to move it and turn it right side up, To keep from having to move the evaporator?
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Posted By: Heavy 488
Date Posted: May/07/2020 at 8:08pm
| Only flow direction should matter, not rotation. |
Posted By: Texas275
Date Posted: May/07/2020 at 8:29pm
| Got it, Thanks |
Posted By: Texas275
Date Posted: May/11/2020 at 5:43pm
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I took my expansion valve to the local Orileys and they brought out 10 different ones to see if they would fit. None of them fit. They all said #6 and #8 male ends but the #8 was too big for my fitting to screw onto. I have ordered one from Nostalgic Air. I’m hoping it fits and I don’t have some weird, one off, expansion valve.
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Posted By: george w
Date Posted: May/11/2020 at 6:31pm
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Using R-12 or R-134 and does it matter ? Shouldn't the usual AMC vendors have the proper valve ? ------------- Long time AMC fan. Ambassador 343, AMX 390, Hornet 360, Spirit 304 and Javelin 390. All but javelin bought new. |
Posted By: 304-dude
Date Posted: May/11/2020 at 6:42pm
Well it could be defective, as it is a low cost item, that is a wee bugger to get to if all finished up. As for difference yes there is. But most are happy with original R12 valve. If your doing a whole new kit or upgrade, I suggest obtaining R134 valve if possible to swap out. It does make it cooler, as the system does not cycle as much. It should cycle once every 2 minutes, but it depends on capacity and tempratures. Between once every minute or two is good. The less cycling the more efficient the system. ------------- 71 Javelin SST body 390 69 crank, 70 block & heads NASCAR SB2 rods & pistons 78 Jeep TH400 w/ 2.76 Low 50/50 Ford-AMC Suspension 79 F150 rear & 8.8 axles Ford Racing 3.25 gears & 9" /w Detroit locker |
Posted By: Texas275
Date Posted: May/11/2020 at 8:42pm
| The evap is set up as 134. It is a cheap model and I may be paying for that now. I put the numbers that are on the valve into google and it only came back with a few results, all of them overseas, and only a couple in English |
Posted By: 401MATCOUPE
Date Posted: May/12/2020 at 5:10am
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Did you change the expansion valve to something other then the original fittings? I am not understanding the issue??? ------------- Ross K. Peterson 68X,GoPac,343,AT,52A(1stCar) 68X,GoPac,390,4sp,52A 69X,GoPac,390,4sp,64A 70X,GoPac,390,4sp,87A,8 70X,GoPac,390,4sp,BBO,8 70 Jav SST,390,AT,BSO 74MatX,401,AT,Prototype 74MatX,401,AT |
Posted By: Mopar_guy
Date Posted: May/12/2020 at 8:14am
Back on page 2 "No OEM parts, everything is aftermarket. " ------------- " http://theamcforum.com/forum/hemilina_topic95889.html" rel="nofollow - Hemilina " My 1973, 5.7 Hemi swapped Javelin |
Posted By: 401MATCOUPE
Date Posted: May/12/2020 at 11:21am
Okay, is aftermarket changes, I can not help any further.....thank you. ------------- Ross K. Peterson 68X,GoPac,343,AT,52A(1stCar) 68X,GoPac,390,4sp,52A 69X,GoPac,390,4sp,64A 70X,GoPac,390,4sp,87A,8 70X,GoPac,390,4sp,BBO,8 70 Jav SST,390,AT,BSO 74MatX,401,AT,Prototype 74MatX,401,AT |
Posted By: Texas275
Date Posted: May/17/2020 at 4:08pm
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Finally got back to the shop with an expansion valve that fit. Evacuated the system, recharged, and it works great. Thanks so much for helping me fix it!!!! Y’all are the best!! Tom
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Posted By: Mopar_guy
Date Posted: May/17/2020 at 5:08pm
I figured that was it. Glad you got it fixed and thanks for reporting back. 
------------- " http://theamcforum.com/forum/hemilina_topic95889.html" rel="nofollow - Hemilina " My 1973, 5.7 Hemi swapped Javelin |
Posted By: Heavy 488
Date Posted: May/17/2020 at 7:56pm
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Posted By: FSJunkie
Date Posted: May/18/2020 at 3:02am
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It is important that the thermal bulb of the expansion valve is attached firmly and directly to the outlet line of the evaporator then wrapped in insulation. Without this, the expansion valve will think the evaporator outlet is warm and the valve will open wider to admit more refrigerant. High side pressure will drop, low side pressure will rise, and the compressor will slug with liquid refrigerant. You will eventually blow the compressor. R12 and R134a expansion valves have a slightly different superheat setting but only slightly and not enough to cause this. There is also the question of system charge amount. Even with a wide open expansion valve, there should not be any bubbles in the sights glass while the compressor is running. Charge amount does not effect the cooling effectiveness of expansion valve type A/C systems. All they care about is that there is enough refrigerant to keep the pickup tube in the receiver/dryer submerged in liquid refrigerant. Adding refrigerant just raises the liquid level. Bubbles in the sight glass means the pickup tube is not submerged, so you add refrigerant until the bubbles disappear then add a little more to give it some reserve. ------------- 1955 Packard 1966 Marlin 1972 Wagoneer 1973 Ambassador 1977 Hornet 1982 Concord D/L 1984 Eagle Limited |
Posted By: rushtonmd
Date Posted: Jun/10/2020 at 6:01pm
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Good call on the expansion valve. I built a custom AC system for a VW and the expansion valve that I got from the company was sized too small for the system. It was a 1ton valve - I did the same thing where I trolled the Oreilly site until I found a 1.5 to. valve with the correct fittings and it all worked great. A lot of AC system companies sell the same valve for all systems and it’s good to check the size against system size - but also they’re super cheap which is nice :) I think mine was like $15. One other thing is there are metric fittings as well as AN fittings so sometimes you’ll have to mix and match with adapters or make sone adapter hoses.
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