Home » Public Forums » GMCnet » yet another dash AC question
| yet another dash AC question [message #274435] |
Fri, 27 March 2015 14:43  |
KB
Messages: 1262
Registered: September 2009
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I'm having trouble charging the dash AC system with Enviro-Safe (duracool equivalent).
Last time, before the hoses got destroyed by the new compressor, I took the consensus advice
and just charged with three 6 ounce cans. It worked more or less, but the compressor cycled off
a lot (which I took to be low refrigerant) and the pressure seemed low.
This time, after replacing the damaged hoses and vacuuming the system to check for leaks, I put in three cans again
and the pressure is still low, something under 10psi at 1500 rpm, so I added more. After two more cans (total of 5),
the pressure at 1500 rpm is about 13psi, and at idle about 28psi.Doesn't seem to be cooling particularly well, though
there is at least condensation on the line at the back of the compressor.
So, is three cans always the case, or do systems vary? Other than the new aluminum compressor, ours is all stock
as far as I know -- no add on evaporators or anything.
I don't know now if it's under or over charged, but am hesitant to just keep adding more refrigerant.
thanks,
Karen
1975 26'
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| Re: [GMCnet] yet another dash AC question [message #274437 is a reply to message #274435] |
Fri, 27 March 2015 15:27  |
emerystora
Messages: 4442
Registered: January 2004
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Did you totally evacuate the system prior to installing the refrigerant? What vacuum level did you reach?
I have never seen a system that needs over 3 cans. 5 cans will not cool it properly. The less you use, the colder it gets. However if you are much less than 3 cans your evaporator will get so cold that the condensate will freeze it up so that air will not flow through it.
You have something else wrong. Did you replace the filter/drier? You should have if you replaced the compressor.
You might also have a bad expansion valve.
Emery Stora
77 Kingsley
Frederick, CO
> On Mar 27, 2015, at 1:43 PM, KB wrote:
>
> I'm having trouble charging the dash AC system with Enviro-Safe (duracool equivalent).
> Last time, before the hoses got destroyed by the new compressor, I took the consensus advice
> and just charged with three 6 ounce cans. It worked more or less, but the compressor cycled off
> a lot (which I took to be low refrigerant) and the pressure seemed low.
>
> This time, after replacing the damaged hoses and vacuuming the system to check for leaks, I put in three cans again
> and the pressure is still low, something under 10psi at 1500 rpm, so I added more. After two more cans (total of 5),
> the pressure at 1500 rpm is about 13psi, and at idle about 28psi.Doesn't seem to be cooling particularly well, though
> there is at least condensation on the line at the back of the compressor.
>
> So, is three cans always the case, or do systems vary? Other than the new aluminum compressor, ours is all stock
> as far as I know -- no add on evaporators or anything.
>
> I don't know now if it's under or over charged, but am hesitant to just keep adding more refrigerant.
>
> thanks,
> Karen
> 1975 26'
>
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| Re: [GMCnet] yet another dash AC question [message #274438 is a reply to message #274437] |
Fri, 27 March 2015 15:45 |
biggreen
Messages: 347
Registered: June 2011
Location: Northeast Florida
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I recently replaced my compressor along with the dryer. My system had already been converted to R-134a. As I had access to equipment from my work, I vacuumed it down and using a coversion chart from R12 to R134, (I had the original R12 charge rate on the original compressor) and charged the system with a little less than 3 lbs R134.
It cools great, but the compressor still cycles on and off . I'm not losing any freon, as the system was checked for leaks and held vacuum.
Like I said, it works fine, just cycles on and off occasionally.
Is this normal?
As long as it cools well, I'm gonna leave it alone.
R.D.
Northeast Florida
77 ex-Palm Beach 403
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| Re: [GMCnet] yet another dash AC question [message #274440 is a reply to message #274437] |
Fri, 27 March 2015 15:58 |
KB
Messages: 1262
Registered: September 2009
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I flushed the hoses, evaporator, and condenser, replaced the receiver/dryer and expansion valve, pulled a good vacuum
which I left overnight and then vacuumed it some more before filling. I see no temp difference on the input vs
output on the receiver/dryer so I don't think it's plugged. When the system equalized with the compressor off,
the pressure was much higher than ambient air (clearly overcharged), so let off some refrigerant until it was at about ambient.
Unfortunately, it made no difference to the cooling.
I'm guessing the new replacement expansion valve I installed is defective.
bummer. Getting tired of taking this thing apart, but summer's coming so not much choice.
thanks,
Karen
1975 26'
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| Re: [GMCnet] yet another dash AC question [message #274443 is a reply to message #274440] |
Fri, 27 March 2015 16:36 |
Bullitthead
Messages: 1411
Registered: November 2013
Karma: 5
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Before you take it apart, did the expansion valve have sense tubing on it? If it does, relocate that away from the evaporator to a warmer area. Other than that I would say the valve is defective or not sized right for the capacity of the evaporator core.
Terry Kelpien
ASE Master Technician
73 Glacier 260
Smithfield, Va.
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| Re: [GMCnet] yet another dash AC question [message #274480 is a reply to message #274440] |
Sat, 28 March 2015 00:55 |
roy1
Messages: 2126
Registered: July 2004
Location: Minden nevada
Karma: 6
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Karen : That low a pressure with 5 cans of refrigerant would suggest a restriction in the liquid line section. Since you didn't have a temperature drop across the drier I would bet you indeed have a defective or improper expansion valve. That sensing bulb should fit the area of the suction line it is clamped too. Generaly it locates on the side of the pipe but it probibly won't matter much. After rereading your post you mention only 125 psi discharge pressure yes the compressor could be suspect if it doesn't pump properly due to defective internal parts you would never arrive at the necessary suction pressure due to a lack of capacity. The expansion valve would be wide open and the compressor could never supply enough refrigerant. I would go with the expansion valve first assuming it wasn't opening enough which could cause the discharge pressure to be lower then you would expect . If the new xpansion valve doesen't correct the problem my next suggestion would be to take advantage of the return warranty on your new compressor. I'm sure you made sure the heat damper is shut and the fan is blowing full bore thru the evap coil .
Roy Keen
Minden,NV
76 X Glenbrook
[Updated on: Sat, 28 March 2015 11:16] Report message to a moderator |
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| Re: [GMCnet] yet another dash AC question [message #274493 is a reply to message #274480] |
Sat, 28 March 2015 10:36 |
KB
Messages: 1262
Registered: September 2009
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Thanks Roy, although the Napa 207307 expansion valve is in the parts exchange list, I really wouldn't
recommend it for our application. The sensing tube is far too long so has to be looped around to fit,
and the end of it is a corkscrew instead of the flat thick bulb of the stock valve. Also, the tube comes
straight out the back of the valve instead of at an angle, so it runs right into the body of the thermostat
mounted inside the compartment. I don't know if the valve I got is defective, or if this particular part
is just not a good match for our application. The AC Delco 15-5481 expansion valve, on the other hand,
is a good physical match to stock so I'm hopeful it will work.
Better, because I only have 4 cans of refrigerant left and no time to order more...
Yes, the heat damper was shut, and I also closed the manual shut-off valve for the heater core in
case that was somehow interfering. The blower was set to high speed.
thanks,
Karen
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| Re: [GMCnet] yet another dash AC question [message #274494 is a reply to message #274492] |
Sat, 28 March 2015 10:34 |
emerystora
Messages: 4442
Registered: January 2004
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Rather than mineral oil I believe I recommended using mineral spirits to flush. This is a solvent. It can then be blown out with compressed air.
You could also use naphtha.
Emery Stora
> On Mar 28, 2015, at 9:21 AM, KB wrote:
>
> I did add oil. The new aluminum compressor came with PAG oil, so as Emery suggested I drained it out
> and rinsed a couple times with mineral oil before adding fresh oil.
>
> Unfortunately, when the compressor ate the smaller of the two hoses, it dumped a lot of oil with the charge.
> I found reference to a GM service bulletin somewhere that said in such a circumstance, add 3-4 ounces of oil
> with the new hose. Don't know if that's good or bad advice, but it's moot now since I had to dump that charge to get
> at the expansion valve. Since I don't know how much is in the system now, may have to take it all apart again to flush and measure.
>
> thanks,
> Karen
> 1975 26'
>
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| Re: [GMCnet] yet another dash AC question [message #274520 is a reply to message #274492] |
Sat, 28 March 2015 17:45 |
 |
Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
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KB wrote on Sat, 28 March 2015 11:21I did add oil.<snip>
Don't know if that's good or bad advice, but it's moot now since I had to dump that charge to get at the expansion valve. Since I don't know how much is in the system now, may have to take it all apart again to flush and measure.
thanks,
Karen
1975 26'
Karen,
Don't sweat it.
You know the way they say "an once for this and another for that"?
They don't know either.
The fact is, if you have too much, it won't matter it will just collect in the condenser and nobody will ever know unless you are in Death Valley in the summer. And maybe not then.
If you have too little, it also won't matter ans long as there is some going by the pump (compressor) and that does not take a lot.
If you are worried, pour in enough for the pump and let it go at that.
Kind of like the oil mix in a old 2-strokes. 16:1, 20:1, 24:1, 48:1 & 50:1 all worked. I ran lots of 24:1 on 50:1 mix and the biggest issue was correcting the mixture.
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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| Re: [GMCnet] yet another dash AC question [message #274526 is a reply to message #274520] |
Sat, 28 March 2015 21:39 |
KB
Messages: 1262
Registered: September 2009
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well, I guess we don't get any AC this trip (as usual).
I pulled the compressor, dumped out the oil (a little under 4 oz) and per the manual refilled with 6 oz fresh oil.
The old oil was green, which I hope is from the refrigerant dye. Otherwise...hmmm...
Installed the pricey new expansion valve, pulled a vacuum, let it sit to check for leaks, charged with three 6oz cans.
If anything, it's worse than before. At idle, the low side is about 18, and the high about 120. My better
half wasn't here to hold it at 1500rpm, but clearly it would have been even lower. Cooling is virtually nonexistent,
though the lines were sweating on one side and mildy warm on the other after a few minutes.
Must be the compressor I guess, as unlikely as that seems. I don't know what else it could be. 
thanks for all the help.
Karen
1975 26'
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| Re: [GMCnet] yet another dash AC question [message #274529 is a reply to message #274526] |
Sun, 29 March 2015 00:25 |
roy1
Messages: 2126
Registered: July 2004
Location: Minden nevada
Karma: 6
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KB wrote on Sat, 28 March 2015 19:39well, I guess we don't get any AC this trip (as usual).
I pulled the compressor, dumped out the oil (a little under 4 oz) and per the manual refilled with 6 oz fresh oil.
The old oil was green, which I hope is from the refrigerant dye. Otherwise...hmmm...
Installed the pricey new expansion valve, pulled a vacuum, let it sit to check for leaks, charged with three 6oz cans.
If anything, it's worse than before. At idle, the low side is about 18, and the high about 120. My better
half wasn't here to hold it at 1500rpm, but clearly it would have been even lower. Cooling is virtually nonexistent,
though the lines were sweating on one side and mildy warm on the other after a few minutes.
Must be the compressor I guess, as unlikely as that seems. I don't know what else it could be.
thanks for all the help.
Karen
1975 26'
since you are confident the expansion valve is not the problem and the liquid line and dryer are not badly restricted.(you would see a noticeable temperature drop at the restriction). You know you are moving the proper amount of air over the evap coil. The compressor would be what I would be looking at . It probibly has a broken discharge reed valve or equivalent component in it that won't allow it to pump it's rated output. Since it is pretty new it should have a warranty ? Bummer hope you don't have to spring the big bucks for another new compressor.
Roy Keen
Minden,NV
76 X Glenbrook
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| Re: [GMCnet] yet another dash AC question [message #274533 is a reply to message #274526] |
Sun, 29 March 2015 07:04 |
Kingsley Coach
Messages: 2691
Registered: March 2009
Location: Nova Scotia Canada
Karma: -34
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Karen
Keep us informed ...
Mike in NS
On Sat, Mar 28, 2015 at 11:39 PM, KB wrote:
> well, I guess we don't get any AC this trip (as usual).
> I pulled the compressor, dumped out the oil (a little under 4 oz) and per
> the manual refilled with 6 oz fresh oil.
> The old oil was green, which I hope is from the refrigerant dye.
> Otherwise...hmmm...
> Installed the pricey new expansion valve, pulled a vacuum, let it sit to
> check for leaks, charged with three 6oz cans.
>
> If anything, it's worse than before. At idle, the low side is about 18,
> and the high about 120. My better
> half wasn't here to hold it at 1500rpm, but clearly it would have been
> even lower. Cooling is virtually nonexistent,
> though the lines were sweating on one side and mildy warm on the other
> after a few minutes.
>
> Must be the compressor I guess, as unlikely as that seems. I don't know
> what else it could be. :(
>
> thanks for all the help.
>
> Karen
> 1975 26'
>
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--
Michael Beaton
1977 Kingsley 26-11
1977 Eleganza II 26-3
Antigonish, NS
Life is too short to hold a grudge; slash some tires and call it even !
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| Re: [GMCnet] yet another dash AC question [message #274543 is a reply to message #274539] |
Sun, 29 March 2015 13:20 |
powwerjon
Messages: 849
Registered: March 2013
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Karen,
You don’t have your location on a general area where you live and that would be very helpful in getting you to the right place to buy stuff.
http://www.duracool.com
Best Place to buy Duracool. I always buy by the case which runs 5.82 a can and if I have any left over I sell to my GMC friends.
J.R. Wright
30' Buskirk Stretch
Michigan
On Location in Tucson
> On Mar 29, 2015, at 9:25 AM, KB wrote:
>
> Thanks Roy, I really appreciate the help. I bought the compressor from Applied, so they'll most likely
> provide a replacement. Finally found the old expansion valve this morning,
> so when I get back might try putting it back in first. I only took it out because "your supposed to".
> While it's not too likely I got two defective brand new expansion valves in a row, it is possible.
> Too bad I'm out of refrigerant or I'd try it now.
>
> I think I'll also switch to real Duracool though it's more expensive. I'm suspicious of the murky green color in the oil,
> but can't figure out what it could be other than dye. While my understanding that Enviro-Safe is equivalent, I suspect they've
> changed their formula (I ordered Glacier Gold originally, but Enviro-Safe is what they sent for whatever reason).
>
> thanks again,
>
> Karen
> 1975 26'
>
>
>
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| Re: [GMCnet] yet another dash AC question [message #274545 is a reply to message #274543] |
Sun, 29 March 2015 13:50 |
emerystora
Messages: 4442
Registered: January 2004
Karma: 13
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Senior Member |
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John
I just clicked on the link you provider and they say their price is $89.88 per case of 12 plus shipping. That comes to $7.49 plus shipping per can. A lot higher than the $5.82 that you say in your email.
Emery Stora
> On Mar 29, 2015, at 12:20 PM, John Wright wrote:
>
> Karen,
> You don’t have your location on a general area where you live and that would be very helpful in getting you to the right place to buy stuff.
>
> http://www.duracool.com
>
> Best Place to buy Duracool. I always buy by the case which runs 5.82 a can and if I have any left over I sell to my GMC friends.
>
> J.R. Wright
> 30' Buskirk Stretch
> Michigan
> On Location in Tucson
>
>> On Mar 29, 2015, at 9:25 AM, KB wrote:
>>
>> Thanks Roy, I really appreciate the help. I bought the compressor from Applied, so they'll most likely
>> provide a replacement. Finally found the old expansion valve this morning,
>> so when I get back might try putting it back in first. I only took it out because "your supposed to".
>> While it's not too likely I got two defective brand new expansion valves in a row, it is possible.
>> Too bad I'm out of refrigerant or I'd try it now.
>>
>> I think I'll also switch to real Duracool though it's more expensive. I'm suspicious of the murky green color in the oil,
>> but can't figure out what it could be other than dye. While my understanding that Enviro-Safe is equivalent, I suspect they've
>> changed their formula (I ordered Glacier Gold originally, but Enviro-Safe is what they sent for whatever reason).
>>
>> thanks again,
>>
>> Karen
>> 1975 26'
>>
>>
>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
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| Re: [GMCnet] yet another dash AC question [message #274546 is a reply to message #274545] |
Sun, 29 March 2015 14:04 |
powwerjon
Messages: 849
Registered: March 2013
Karma: -2
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Senior Member |
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Emery,
You are again correct, I was on the wrong line.
J.R. Wright
30' Buskirk Stretch
Michigan
On Location in Tucson
> On Mar 29, 2015, at 11:50 AM, Emery Stora wrote:
>
> John
> I just clicked on the link you provider and they say their price is $89.88 per case of 12 plus shipping. That comes to $7.49 plus shipping per can. A lot higher than the $5.82 that you say in your email.
>
> Emery Stora
>
>> On Mar 29, 2015, at 12:20 PM, John Wright wrote:
>>
>> Karen,
>> You don’t have your location on a general area where you live and that would be very helpful in getting you to the right place to buy stuff.
>>
>> http://www.duracool.com
>>
>> Best Place to buy Duracool. I always buy by the case which runs 5.82 a can and if I have any left over I sell to my GMC friends.
>>
>> J.R. Wright
>> 30' Buskirk Stretch
>> Michigan
>> On Location in Tucson
>>
>>> On Mar 29, 2015, at 9:25 AM, KB wrote:
>>>
>>> Thanks Roy, I really appreciate the help. I bought the compressor from Applied, so they'll most likely
>>> provide a replacement. Finally found the old expansion valve this morning,
>>> so when I get back might try putting it back in first. I only took it out because "your supposed to".
>>> While it's not too likely I got two defective brand new expansion valves in a row, it is possible.
>>> Too bad I'm out of refrigerant or I'd try it now.
>>>
>>> I think I'll also switch to real Duracool though it's more expensive. I'm suspicious of the murky green color in the oil,
>>> but can't figure out what it could be other than dye. While my understanding that Enviro-Safe is equivalent, I suspect they've
>>> changed their formula (I ordered Glacier Gold originally, but Enviro-Safe is what they sent for whatever reason).
>>>
>>> thanks again,
>>>
>>> Karen
>>> 1975 26'
>>>
>>>
>>>
>>> _______________________________________________
>>> GMCnet mailing list
>>> Unsubscribe or Change List Options:
>>> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
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