Under Dash A/C - Opinions Please - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Huskerboy2 · 03-09-2006, 05:35 PM

My 1 ton has an underdash A/C unit in it. It doesn't work. I could maybe get it to work, if I played around with it. It sounds like it wants to work. Plus, it looks hideous under there, in my opinion. At any rate, I'm thinking about just pulling the thing.

I've played around with the idea of a cab swap and going the factory A/C route, but I'm not real excited about that. So, am I crazy for going no air at all? Maybe I should ask myself this question in about August.

Also, are these old under dash A/C units worth anything, even as parts??

**dennislbrooks** · 03-09-2006, 05:39 PM

most likely if you have a wife she will not ride with you in Texas

Huskerboy2 · 03-09-2006, 05:50 PM

It's not the lack of A/C that keeps her out of that truck, but you are right, that doesn't help.

davidh · 03-09-2006, 06:21 PM

Depends on how you are using the truck. If you work out of it and are in and out of the truck, running around town it's harder to keep cool. Now if you are running down the interstate or loop 360. 183HWY AC would be nice. Not arriving with your back stuck to the seat in sweat.
Maybe this is one of those old wives tales but I've had people tell me those old under dash ac units worked great if not better than factory. Being your in S. TX Im sure you have plenty of AC repair shops and someone could look at it. maybe for a few hundred bucks it could be fixed. I saw in car craft where they put an AC together out of junkyard things, it was an under dash unit it worked and was cheap.

ozzcart_83 · 03-09-2006, 06:27 PM

I would have to say before you go doing a cab swap and spending all that money on going that route then you should try and fix the under the dash unit. In my opinion, my cab is a factory air cab and I am going to put vintage air in it and not even mess with the factory air stuff. The reason I say this is because factory is nice but it was factory air back in the 1970s, not today. One of the trucks I had before the one I have now, had all the stuff to put it back factory (A/C) and it worked but not very good. The 1970s unit doesn't work very well and you would be happier with the vintage style for the simple fact that it would get colder.

mvpco · 03-09-2006, 06:37 PM

Quote:

Originally Posted by ozzcart_83

I would have to say before you go doing a cab swap and spending all that money on going that route then you should try and fix the under the dash unit. In my opinion, my cab is a factory air cab and I am going to put vintage air in it and not even mess with the factory air stuff. The reason I say this is because factory is nice but it was factory air back in the 1970s, not today. One of the trucks I had before the one I have now, had all the stuff to put it back factory (A/C) and it worked but not very good. The 1970s unit doesn't work very well and you would be happier with the vintage style for the simple fact that it would get colder.

Well, I agree with you now that I have put the factory one in mine, nice, cold, but just not like todays A/C,(I did not think of it that way till you mentioned it) I spent more going the factory route and if I had to do it again I would go with a vintage air type design. The factory sure looks nice and does work, but if you are really going to use it as a daily driver, I would go vintage air. you might even come out cheaper and have a current design for todays standards.

just my .02 worth

Jeff Smith
Pensacola, FL,
Pics of how I did mine
http://www.mvpc.com/1972chevy.htm

mrein3 · 03-10-2006, 02:22 PM

Quote:

Originally Posted by ozzcart_83

I would have to say before you go doing a cab swap and spending all that money on going that route then you should try and fix the under the dash unit. In my opinion, my cab is a factory air cab and I am going to put vintage air in it and not even mess with the factory air stuff. The reason I say this is because factory is nice but it was factory air back in the 1970s, not today. One of the trucks I had before the one I have now, had all the stuff to put it back factory (A/C) and it worked but not very good. The 1970s unit doesn't work very well and you would be happier with the vintage style for the simple fact that it would get colder.

I couldn't disagree with a post more than this.
Today's automotive AC units aren't even in the same universe as the R12 units the factory installed in the early 70s.

If you have an R12 system working properly and full of R12, you will be cold. In all my newer vehicles, I'm never more than comfortable with the R134a units.

In my 1972 Chevelle the factory air is so cold that when I get out at the mailbox after work my glasses fog up. That system was gone over by me in 1989. I replaced the receiver/dryer, all the o-rings, and gave it a fresh charge of R12. I haven't added a drop since then.

I hate to admit it but the Ford R12 AC units from back then are even better. And they are more durable.

In the 80s I worked at a automotive repair shop. For two summers I fixed ACs. In all those years I fixed countless GM airconditioners. I fixed one Ford. It was a big old 76 or so LTD. It needed a POA valve. If I had a nickle for every ac manifold hose assembly I replaced on various GM 4-cylinder power cars, I wouldn't need my current job.

All that being said I'm putting factory air on my truck. Since R12 is scarce and expensive I've re-calibrated my POA valve to use R134a. All I have left to complete the job is to buy a new receiver/dryer, evacuate the system, and install the R134a I bought off the clearance rack at Wal*Mart last fall. I THINK this will work similar to R12 in the unit because of the way the older systems work verses new.

As far as price, I'll have WAY less into the factory stuff verses the aftermarket units available.

hotrodhomi · 03-10-2006, 02:29 PM

Quote:

Originally Posted by mrein3

I couldn't disagree with a post more than this.
Today's automotive AC units aren't even in the same universe as the R12 units the factory installed in the early 70s.

If you have an R12 system working properly and full of R12, you will be cold. In all my newer vehicles, I'm never more than comfortable with the R134a units.

So are you saying that the older system works better because of the R12? If this is the case why are you doing the conversion to R134a? Availability? If you were going to use R134a anyway, why wouldn't you use a system that was designed for it?

mrein3 · 03-10-2006, 03:54 PM

Quote:

Originally Posted by hotrodhomi

So are you saying that the older system works better because of the R12?

Yes and no. R12 is a better product for cooling. However I've never used a old style ac system (constantly running, pressure handled by POA valve) with R134a

Quote:

Originally Posted by hotrodhomi

If this is the case why are you doing the conversion to R134a?
Availability?

Price. Availability. And as I stated in my previous post I THINK it will be ok because of the design of the old R12 system.

Quote:

Originally Posted by hotrodhomi

If you were going to use R134a anyway, why wouldn't you use a system that was designed for it?

Systems that are designed for it don't use a POA valve. They cycle on and off while you drive down the road. The older compressors are bigger, probably consume more horsepower, but last longer.

ozzcart_83 · 03-10-2006, 07:40 PM

Quote:

Originally Posted by hotrodhomi

So are you saying that the older system works better because of the R12? If this is the case why are you doing the conversion to R134a? Availability? If you were going to use R134a anyway, why wouldn't you use a system that was designed for it?

Availability and cost is the reason why everyone converts to 134. And yes I would say that R12 does make the air very cold. That is if you get lucky, the reason I say that is, when I restored my factory air unit it didn't work well, (not like a vintage unit) but on the flip side of that people get lucky with the original and it works like he said, (frosts the windows when you roll them down!!!). I think that is what everyone is looking for. The reason I say to go for the vintage is cost and availabilty, The initial cost may be more but its worth it in the end. They even make a unit for the 67-72s that makes it seem like there has been nothing done. My dad is getting ready to put in in his 68 burb and the total system from venting all the way down to the compressor and dryer will run him $2000. I will ask him where he is buying it from. That may be a little much right off but you won't have to worry about it for a long time!!!

Huskerboy2 · 03-09-2006, 06:30 PM

What are the vintage air units running these days?

Huskerboy2 · 03-09-2006, 06:31 PM

I meant to say, what do they cost these days?

davidh · 03-10-2006, 10:18 AM

I've seen some updated underdash AC units that looked similar to older under dash units back then I think they are going for $795 complete.

boundstaffpress · 03-10-2006, 02:35 PM

R12 units (properly functioning) do cool off better than todays r134a stuff. Like mrein3, I had a 71 malibu with r12 that would freeze me out. I changed it over to R134a, and it would do OK on the highway, but was hardly worth it in town.

R12 is too expensive to use in my opinion, and a retrofitted system won't chill like a system designed for R134a. Underdash units cost $1500 installed around here, and about that to buy a custom fit and install yourself. There is plenty of work to installing a unit, but nothing that an average handyman can't tackle.

When I was done installing a unit in my Nova Wagon, it cost me $2000 with parts and refrigerant. Check out my signature link and click on the nova A/C link. I have pics and description of some of the troubles I had. I don't mention, that I routed the cooling hose right over the exhaust manifold, and the system didn't work for the first summer I had it. I eventually wrapped it in pipe insulation and it worked a lot better. I like Vintage Air, because I used Classic Auto Air, and didn't like the support I got. They do have a less expensive product though. Same parts.

**dennislbrooks** · 03-10-2006, 04:09 PM

Everyone agrees that the R12 is the coldest -- but for the ease of adding a can of R134a and its cost --anything I have to replace (like a compressor or a complete setup) is 134a going forward.

**john** · 03-10-2006, 06:43 PM

mrein3 old air products makes a conversion kit from poa-dryer setup to an orifice accumulator setup. I heard it works good with r134a, but I havent tried it. I know some board members have. John

jay-dawg · 03-10-2006, 07:15 PM

Have a related question. Are the aftermarket units "stand alone" meaning they have their own powersupply wiring etc? Does anyone have a copy of the installation instructions for our year trucks from the aftermarket companies?

Thanks,
Jay

formula_raider · 03-10-2006, 07:48 PM

Just for AC purposes, along with my 72 Pickup...I have a 70 Oldsmoble 98 that I completely re-did the stock AC. Just flushed out the stock condensor and evaporator. Replace the big A6 compressor, orfice tube, receiver-dryer, and got the Old Air POA upgrade kit which changes it to the new cycle switch type system as seen in newer cars. All the pressure and return hoses replaced. So basiclly a stock system with 134-A freon. With a thermometer at the AC vent I got today with an outside temp of 88 Degrees. Between 50-53 Degrees on the hwy at 70MPH. At times when I slow down it gets down to 47....but never below 45. It is comfortable but not COLD as you would see the newer cars. Im sure if I had R12 in this system it would run colder...but thats the nature of the beast. I also have (2) electric condensor fans that turn on when the compressor kicks in. I think it is in the design of the condensor. R12 ran at lower pressures and heat...the condensors could remove the heat better and cool the interior better. R134-A runs at a higher pressure and the older type condensors have a harder time getting rid of the heat. I have a complete OLD Air system that I am putting on my 72 and will record the interior temperature readings when done.

03-09-2006, 05:35 PM	#1
Huskerboy2 Senior Member Join Date: Feb 2001 Location: Austin, Texas, USA Posts: 1,628	Under Dash A/C - Opinions Please My 1 ton has an underdash A/C unit in it. It doesn't work. I could maybe get it to work, if I played around with it. It sounds like it wants to work. Plus, it looks hideous under there, in my opinion. At any rate, I'm thinking about just pulling the thing. I've played around with the idea of a cab swap and going the factory A/C route, but I'm not real excited about that. So, am I crazy for going no air at all? Maybe I should ask myself this question in about August. Also, are these old under dash A/C units worth anything, even as parts?? __________________ '72 Chevy Blazer

03-09-2006, 05:39 PM	#2
dennislbrooks Senior Member Join Date: Feb 2004 Location: Williamsburg, Ohio Posts: 1,787	Re: Under Dash A/C - Opinions Please most likely if you have a wife she will not ride with you in Texas

03-09-2006, 05:50 PM	#3
Huskerboy2 Senior Member Join Date: Feb 2001 Location: Austin, Texas, USA Posts: 1,628	Re: Under Dash A/C - Opinions Please It's not the lack of A/C that keeps her out of that truck, but you are right, that doesn't help. __________________ '72 Chevy Blazer

03-09-2006, 06:21 PM	#4
davidh Senior Member Join Date: Feb 2004 Location: Ponca city now kingfisher Oklahoma Posts: 1,221	Re: Under Dash A/C - Opinions Please Depends on how you are using the truck. If you work out of it and are in and out of the truck, running around town it's harder to keep cool. Now if you are running down the interstate or loop 360. 183HWY AC would be nice. Not arriving with your back stuck to the seat in sweat. Maybe this is one of those old wives tales but I've had people tell me those old under dash ac units worked great if not better than factory. Being your in S. TX Im sure you have plenty of AC repair shops and someone could look at it. maybe for a few hundred bucks it could be fixed. I saw in car craft where they put an AC together out of junkyard things, it was an under dash unit it worked and was cheap.

03-09-2006, 06:27 PM	#5
ozzcart_83 Registered User Join Date: Jan 2006 Location: Ottawa, Kansas Posts: 5	Re: Under Dash A/C - Opinions Please I would have to say before you go doing a cab swap and spending all that money on going that route then you should try and fix the under the dash unit. In my opinion, my cab is a factory air cab and I am going to put vintage air in it and not even mess with the factory air stuff. The reason I say this is because factory is nice but it was factory air back in the 1970s, not today. One of the trucks I had before the one I have now, had all the stuff to put it back factory (A/C) and it worked but not very good. The 1970s unit doesn't work very well and you would be happier with the vintage style for the simple fact that it would get colder.

03-09-2006, 06:30 PM	#11
Huskerboy2 Senior Member Join Date: Feb 2001 Location: Austin, Texas, USA Posts: 1,628	Re: Under Dash A/C - Opinions Please What are the vintage air units running these days? __________________ '72 Chevy Blazer

03-09-2006, 06:31 PM	#12
Huskerboy2 Senior Member Join Date: Feb 2001 Location: Austin, Texas, USA Posts: 1,628	Re: Under Dash A/C - Opinions Please I meant to say, what do they cost these days? __________________ '72 Chevy Blazer

03-10-2006, 10:18 AM	#13
davidh Senior Member Join Date: Feb 2004 Location: Ponca city now kingfisher Oklahoma Posts: 1,221	Re: Under Dash A/C - Opinions Please I've seen some updated underdash AC units that looked similar to older under dash units back then I think they are going for $795 complete.

03-10-2006, 02:35 PM	#14
boundstaffpress Jamie Hyneman is my twin Join Date: Nov 2005 Location: La Junta, Colorado Posts: 705	Re: Under Dash A/C - Opinions Please R12 units (properly functioning) do cool off better than todays r134a stuff. Like mrein3, I had a 71 malibu with r12 that would freeze me out. I changed it over to R134a, and it would do OK on the highway, but was hardly worth it in town. R12 is too expensive to use in my opinion, and a retrofitted system won't chill like a system designed for R134a. Underdash units cost $1500 installed around here, and about that to buy a custom fit and install yourself. There is plenty of work to installing a unit, but nothing that an average handyman can't tackle. When I was done installing a unit in my Nova Wagon, it cost me $2000 with parts and refrigerant. Check out my signature link and click on the nova A/C link. I have pics and description of some of the troubles I had. I don't mention, that I routed the cooling hose right over the exhaust manifold, and the system didn't work for the first summer I had it. I eventually wrapped it in pipe insulation and it worked a lot better. I like Vintage Air, because I used Classic Auto Air, and didn't like the support I got. They do have a less expensive product though. Same parts. __________________ Justin SOLD 1967 K10 Fleetside, 283, Front and Rear Posi SOLD Color Wiring Diagrams Now in High Resolution V8 and Cab and Cab and Chassis

03-10-2006, 04:09 PM	#15
dennislbrooks Senior Member Join Date: Feb 2004 Location: Williamsburg, Ohio Posts: 1,787	Re: Under Dash A/C - Opinions Please Everyone agrees that the R12 is the coldest -- but for the ease of adding a can of R134a and its cost --anything I have to replace (like a compressor or a complete setup) is 134a going forward.

03-10-2006, 06:43 PM	#16
john member #16 Join Date: Dec 1999 Location: Yuba City Ca. Posts: 3,618	Re: Under Dash A/C - Opinions Please mrein3 old air products makes a conversion kit from poa-dryer setup to an orifice accumulator setup. I heard it works good with r134a, but I havent tried it. I know some board members have. John __________________ john http://67-72chevytrucks.com/vboard/showgroups.php board vendors http://www.flickr.com/photos/1745471...7602865984234/

03-10-2006, 07:15 PM	#17
jay-dawg chevelito Join Date: Jun 2001 Location: Honolulu, HI USA Posts: 1,609	Re: Under Dash A/C - Opinions Please Have a related question. Are the aftermarket units "stand alone" meaning they have their own powersupply wiring etc? Does anyone have a copy of the installation instructions for our year trucks from the aftermarket companies? Thanks, Jay __________________ New deadline...when my son can drive. Aloha from Honolulu, HI

03-10-2006, 07:48 PM	#18
formula_raider Registered User Join Date: Nov 2005 Location: San Marcos, Tx Posts: 62	Re: Under Dash A/C - Opinions Please Just for AC purposes, along with my 72 Pickup...I have a 70 Oldsmoble 98 that I completely re-did the stock AC. Just flushed out the stock condensor and evaporator. Replace the big A6 compressor, orfice tube, receiver-dryer, and got the Old Air POA upgrade kit which changes it to the new cycle switch type system as seen in newer cars. All the pressure and return hoses replaced. So basiclly a stock system with 134-A freon. With a thermometer at the AC vent I got today with an outside temp of 88 Degrees. Between 50-53 Degrees on the hwy at 70MPH. At times when I slow down it gets down to 47....but never below 45. It is comfortable but not COLD as you would see the newer cars. Im sure if I had R12 in this system it would run colder...but thats the nature of the beast. I also have (2) electric condensor fans that turn on when the compressor kicks in. I think it is in the design of the condensor. R12 ran at lower pressures and heat...the condensors could remove the heat better and cool the interior better. R134-A runs at a higher pressure and the older type condensors have a harder time getting rid of the heat. I have a complete OLD Air system that I am putting on my 72 and will record the interior temperature readings when done.



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