Home » Public Forums » GMCnet » Air Conditioning (Question about Dash Air Conditioning)
| Air Conditioning [message #253274] |
Wed, 25 June 2014 19:40  |
stick miller
Messages: 1036
Registered: March 2010
Location: Americus, Georgia
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OK I have a76 Eleganza and I need some a/c advice. I have adequate airflow but feel like I am not getting the temperature low enough. I'm using duracool and at 1500 rpm I have 20 lbs of pressure. I do not believe I have a leak.
It's 90 degrees here today and the air coming out of the vent is around 60 degrees. I think it should do better. The hose in the engine compartment that should be cold is actually just cool.
Additionally, I have a second blower box behind the driver seat. My understanding is that this blower runs off the engine compressor and yet, the air coming out of that blower is suddenly warm.
And the suction (large) line is at about ambient temperature, maybe more. There's not a heater element in that unit. Since this is a "closed" system much like if you had rear air in a Suburban what could be causing the difference between the dash air and this?
Any suggestions would be appreciated.
Stick Miller
'78 Royale - "White Trash" - she left me for another man
'76 Eleganza - "Cousin Eddie" Sold
'84 Bluebird Wanderlodge - "Past Tents"
Americus, GA
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| Re: Air Conditioning [message #253275 is a reply to message #253274] |
Wed, 25 June 2014 19:50  |
tphipps
Messages: 3005
Registered: August 2004
Location: Spanish Fort, AL
Karma: 9
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Are you sure that the second coil, under the seat is getting cold? In the normal fashion, this would be parallel to the in dash A/C system. Perhaps there might be a cut-off valve that will stop refrigerant flow to the second unit?
Just wild guessing here.
Tom, MS II
2012 Phoenix Cruiser model 2552
KA4CSG
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| Re: Air Conditioning [message #253276 is a reply to message #253275] |
Wed, 25 June 2014 20:02 |
stick miller
Messages: 1036
Registered: March 2010
Location: Americus, Georgia
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That makes sense. The hoses from the dash air to the underseat air are not cold. Is there something else that could be blocking the travel?
Stick Miller
'78 Royale - "White Trash" - she left me for another man
'76 Eleganza - "Cousin Eddie" Sold
'84 Bluebird Wanderlodge - "Past Tents"
Americus, GA
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| Re: Air Conditioning [message #253278 is a reply to message #253276] |
Wed, 25 June 2014 20:17 |
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Richard Andis
Messages: 261
Registered: January 2013
Location: HELL Paso, TX
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A temp differential of 30 degrees between intake and discharged air is almost unbelievable. Most of the time it's somewhere around 20-25 degrees. Are you chilling outside air or recirculated air? It really doesn't matter. A single pass through the evaporator coil should drop temps about 25 degrees.
As for the extra evaporator blower behind the driver's seat, you may need to hand-over-hand both suction and discharge lines in order to find some sort of shutoff valve. I assume this is some sort of non-OEM setup.
Valhalla - 1978 GMC Royale rear twin [SOLD]
Walküre - 1974 VW Thing (Toad)
[Updated on: Wed, 25 June 2014 20:20] Report message to a moderator |
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| Re: Air Conditioning [message #253298 is a reply to message #253278] |
Wed, 25 June 2014 23:11 |
Bullitthead
Messages: 1411
Registered: November 2013
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30 degree drop is good, 40 would be optimal, but since Al Gore and Dupont teamed up and took away the efficient R=12 you may not ever get that 40 without a redesigned system that gives the refrigerant extra time to change state before it fills the evaporator. If the unit under the seat is an evaporator, then it will have its own expansion valve, and that is the most likely culprit to stop the flow through the unit. I don't know why these remote valves have a tendency to get stuck, but I have had to replace several in vans, limousines, and several Suburbans and Tahoes. Maybe there is some trash from the system that found its way in there and got stopped by the valve or the valve is stuck due to some chemical reaction going on in the system. You can try smacking the valve with a solid object (not a hammer, more like a screwdriver handle or heavy pocket knife or leatherman tool) while the system is operating and the pressure is against the valve. Most likely you will have to remove the refrigerant, disconnect the lines and try to reverse flush just that part of the system to see if anything comes out. If you can't get air to flow through, then you will probably have to replace the valve.
Some of the large trucks I have worked on have had a shut-off valve for the sleeper compartment so that can be left at ambient while the driver gets the most cool in the cab while driving. If the underseat system has its own control, it's possible that there is a shutoff valve somewhere in the high line before the expansion valve. Sometimes flushing carb cleaner back through the expansion valve will free it up, but be sure you get that cleaned outta there with plenty of air before reassembling the system.
Terry Kelpien
ASE Master Technician
73 Glacier 260
Smithfield, Va.
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| Re: Air Conditioning [message #253310 is a reply to message #253298] |
Thu, 26 June 2014 07:14 |
stick miller
Messages: 1036
Registered: March 2010
Location: Americus, Georgia
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Your reply makes the most sense in light of the fact that it was working earlier in the month. Expansion valve is probably the culprit. Thanks
Stick Miller
'78 Royale - "White Trash" - she left me for another man
'76 Eleganza - "Cousin Eddie" Sold
'84 Bluebird Wanderlodge - "Past Tents"
Americus, GA
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| Re: [GMCnet] Air Conditioning [message #253314 is a reply to message #253313] |
Thu, 26 June 2014 08:53 |
C Boyd
Messages: 2629
Registered: April 2006
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Hi Emery, In my back yard sperience of keeping a small fleet of identical Kenworths ACs working daily that some will work better than others. I had one that if left running at night with AC on it would frost the windows. Bout the best I can usually get is 42* out the vents. When charging a system I stop when the low side line is sweating at the compressor. That is the best that system will do. I do use gauges and monitor pressures. Usually with duracool bout 26 on the low side with our high humidity.
Are your eyes doing OK??
emerystora wrote on Thu, 26 June 2014 08:59Using Duracool in a stock GMC system many of us have gotten a 40 degree or more temperature drop. It cools much better than the original R-12.
Emery Stora
77 Kingsley
Frederick, CO
On Jun 25, 2014, at 7:17 PM, Richard Andis wrote:
> A temp differential of 30 degrees between intake and discharged air is almost unbelievable. Most of the time it's somewhere around 20-25 degrees. Are
> you chilling outside air or recirculated air?
>
> As for the extra evaporator blower behind the driver's seat, you may need to hand-over-hand both suction and discharge lines in order to find some
> sort of shutoff valve. I assume this is some sort of non-OEM setup.
> --
> Valhalla - 1978 GMC Royale rear twin [SOLD]
> Walküre - 1974 VW Thing (Toad)
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> GMCnet mailing list
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C. Boyd
76 Crestmont
East Tennessee
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| Re: Air Conditioning [message #253397 is a reply to message #253274] |
Thu, 26 June 2014 20:53 |
lotsofspareparts
Messages: 726
Registered: May 2014
Location: Arlington, WA
Karma: -9
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Sorry, not trying to hijack a thread but where do you buy Duracool?
Is it a direct replacement for r-12?
My dash AC system works, but after sitting for 12 years it is not blowing very cold.
There is still pressure there though as the compressor does kick on.
Jared
Jared & Tina Lazaron + 14yr old Daughter.....
77 Eleganza II "Recherché".....
73 Canyon Lands 230 "Elephant"
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| Re: Air Conditioning [message #253399 is a reply to message #253397] |
Thu, 26 June 2014 21:13 |
A Hamilto
Messages: 4508
Registered: April 2011
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lotsofspareparts wrote on Thu, 26 June 2014 20:53Sorry, not trying to hijack a thread but where do you buy Duracool?
Is it a direct replacement for r-12?
My dash AC system works, but after sitting for 12 years it is not blowing very cold.
There is still pressure there though as the compressor does kick on.
Jared Practially speaking, Duracool is a direct replacement for R-12. Legally it is not. You can not LEGALLY convert from R-12 directly to Duracool. If your system is R-134a, and if your state allows hydrocarbon refrigerants in automotive applications, it IS legal to convert to Duracool. To stay on the correct side of the law, you need to make sure that your state does not prohibit the use of hydrocarbon refrigerants in automotive applications, AND you need to perform a "good faith" conversion to R-134a. After you are not satisfied with the performance of the system with R-134a, you can convert it to Duracool, if your state allows it. It is illegal to perform a "sham" conversion from R-12 to R-134a just to be able to then convert to Duracool.
That's the law. Has anyone ever been prosecuted for converting directly from R-12 to Duracool? I dunno.
According to http://www.epa.gov/ozone/snap/refrigerants/hc12alng.html "The following 19 states ban the use of flammable refrigerants such as HC-12a® and DURACOOL 12a® in motor vehicle air conditioning, regardless of the original refrigerant: Arkansas, Arizona, Connecticut, Florida, Idaho, Indiana, Iowa, Kansas, Louisiana, Maryland, Nebraska, North Dakota, Oklahoma, Texas, Utah, Virginia, Wisconsin, Washington, and the District of Columbia."
Check out the web page for more answers.
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| Re: Air Conditioning [message #253403 is a reply to message #253399] |
Thu, 26 June 2014 21:37 |
lotsofspareparts
Messages: 726
Registered: May 2014
Location: Arlington, WA
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Anyone in one of the non prohibited states wanna sell me some Duracool?
My father is a police officer, he would like some too.
Jred
Jared & Tina Lazaron + 14yr old Daughter.....
77 Eleganza II "Recherché".....
73 Canyon Lands 230 "Elephant"
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| Re: Air Conditioning [message #253409 is a reply to message #253403] |
Thu, 26 June 2014 23:18 |
Bob de Kruyff
Messages: 4260
Registered: January 2004
Location: Chandler, AZ
Karma: 1
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lotsofspareparts wrote on Thu, 26 June 2014 20:37Anyone in one of the non prohibited states wanna sell me some Duracool?
My father is a police officer, he would like some too.
Jred
Once you get through the online BS about the legalities of all this, google Worthington Parts and order it. They have many locations and although the unit cost is low, shipping can add up. You will be pleased with the results assuming you don't committ suicide over the guilt feelings.
Bob de Kruyff
78 Eleganza
Chandler, AZ
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| Re: Air Conditioning [message #253414 is a reply to message #253406] |
Fri, 27 June 2014 00:07 |
Bullitthead
Messages: 1411
Registered: November 2013
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I put a product called "Macfreeze" in the GMC after having good results with it in my 84 Bronco II. It's not available under that name anymore, but it is probably the same formula as Duracool because it is operating at the same pressures that people are reporting for the Duracool. I'm sure it's a mixture of dinosaur parts and cow farts with a little Chanel #666 thrown in for flavor. Definitely has a pleasant odor. It works with the mineral oil that these systems were designed for, and is less work on the compressor, so it requires less horsepower. With a worn down compressor it needs a few more RPM than idle to get the best cooling, but it doesn't overheat the engine, doesn't require an extra cooling fan for the condenser, doesn't leak through the hoses, and doesn't disintegrate the o-rings and piston rings. Not concerned about the freon cops, just what is right and wrong.
When charging any of these A/C systems with any substance, I do what Chuck Boyd said and fill it until I get cold back to the compressor. That helps cool the pump some and insures that there is still some cold leftover after the refrigerant has done its job in the evaporator. I also DO NOT use the Max A/C position when charging if that position on the controls makes the system recirculate the cabin air. I prefer to have outside air flowing through the evaporator on the highest blower setting (leave an opening when blowing outside air into the vehicle to insure proper airflow) so I can be sure I am getting the most work out of the refrigerant that the system can provide. After that plateau is reached I stop charging and close the windows all the way and put the system on recirculate to check out the lowest possible temperature the system will deliver.
If I am just replacing broken parts and recharging a system the I just put in what the manufacturer indicates on the label or in the service manual and send the customer on their way. I only do the experimentation on my own fleet of vehicles, and I always get better results than what I get if I follow the EPA guidelines/regulations, with a lot lot less wasted time and horsepower and money, and don't contribute nearly as much heat to the environment. The EPA needs to be disbanded, reeducated, and reassembled as an agency that has efficiency as its primary objective. Then they could take Ford to task for coming out with those idiotic springlock couplings that leaked all the R-12 out right when Duponts patent expired on the stuff, and go after Chrysler for the Mexican evaporators that leaked tons of R-134 out before the vehicles were even paid for.
Terry Kelpien
ASE Master Technician
73 Glacier 260
Smithfield, Va.
[Updated on: Fri, 27 June 2014 00:09] Report message to a moderator |
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| Re: Air Conditioning [message #253418 is a reply to message #253409] |
Fri, 27 June 2014 02:44 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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I saw the Duracool Police sitting outside of the Duracool store in my prohibited state. They appeared to be taking down license plate numbers of everyone for leaving the store for investigation. They was big dog in the back sniffing with his head out of the window sniffing of the cars as they went by.
Since we stopped enforcing drug laws and pursuing illegal immigrants, those cops and sniffer dogs have been converted to finding Duracool violators and enforcing the Duracool laws.
If you believe the previous Internet hype in this thread then I assume that you will believe my above Internet story.
I buy Duracool in Indiana at a local Leesburg, Indiana store. We are supposedly one of the prohibited states. Dan also buys it locally in Missouri.
Go on line and order it from Worthington Ag Parts and they will mail it to you. Shipping is not much.
http://www.worthingtonagparts.com/about/locations.aspx
http://www.worthingtonagparts.com/parts/view/WN-D12A06/refrigerant-duracool-12a-6-oz.-recharge-can.aspx
It is also available from other on line dealers but I have been using Worthington for years so I do not know about the others.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] Air Conditioning [message #253431 is a reply to message #253428] |
Fri, 27 June 2014 09:55 |
stick miller
Messages: 1036
Registered: March 2010
Location: Americus, Georgia
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See if you can get a price by the case. Seems like it was cheaper a year or so ago. (What wasn't).
Meanwhile back to the topic of my puny air conditioning. If I understand this correctly, there is an expansion valve both in the conventional system and the PO-added secondary system. If I'm unsuccessful in "knocking it loose" then it looks like replacement of the faulty expansion valve. When I do that I'll lose all my coolant so why then not replace the other expansion valve and flush the system evacuate and recharge?
'splain the process to me, please. Might as well fix it right.
Stick Miller
'78 Royale - "White Trash" - she left me for another man
'76 Eleganza - "Cousin Eddie" Sold
'84 Bluebird Wanderlodge - "Past Tents"
Americus, GA
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| Re: [GMCnet] Air Conditioning [message #253460 is a reply to message #253435] |
Fri, 27 June 2014 18:15 |
Carl S.
Messages: 4186
Registered: January 2009
Location: Tucson, AZ.
Karma: 13
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Like Emery, I get it from: http://bennettsupply.net/index.html The first time I ordered some from them I asked if they could ship it to AZ. Their reply was "I can ship it ANYwhere". Serious scofflaw that I am, I have used it in several vehicles with varying success. I currently have VERY cold AC in my Jeep Cherokee, but have not yet converted the GMC to it.
Carl Stouffer
'75 ex Palm Beach
Tucson, AZ.
Chuck Aulgur Reaction Arm Disc Brakes, Quadrabags, 3.70 LSD final drive, Lenzi knuckles/hubs, Dodge Truck 16" X 8" front wheels, Rear American Eagles, Solar battery charging. GMCSJ and GMCMI member
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