how cold does you a/c blow ? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

*rage'nrat638* · 06-15-2006, 11:24 PM

mine with the stock system except a sanden 134r compressor max's out at 60 deg's

any body else got a better temp using 134r?

kansas city cheyenne · 06-15-2006, 11:25 PM

Just depends how fast I am going and how many windows I have down. HA HA

FRENCHBLUE72 · 06-18-2006, 01:39 AM

Quote:

Originally Posted by kansas city cheyenne

Just depends how fast I am going and how many windows I have down. HA HA

yep me too unless the top is off the blazer..

**Ricks1971** · 06-16-2006, 12:37 AM

It should get colder that? I think my 72 was getting 47 degrees out of the vent when I recharged. Thats with 134r

220mph · 06-16-2006, 12:48 AM

39f with an outside temp of 78f

220mph · 06-16-2006, 12:49 AM

If I want it really cold, I'll take my mother-in-law for a ride

89 crew · 06-16-2006, 01:06 AM

Quote:

Originally Posted by rage'nrat638

mine with the stock system except a sanden 134r compressor max's out at 60 deg's

any body else got a better temp using 134r?

I would check the switcher between the heater core and the ac. I bet yours is sticking or not moving at all.

ERASER5 · 06-16-2006, 03:51 AM

Who charged the system? How much r134a charge was used? Was the system flushed before the new compressor was mounted? How much oil was put in? Was the expansion valve replaced? How about the reciever/dryer? All of these will affect performance.

A common mistake is to look up the propper r12 charge for that system and charge the same amount of r134a. The result is poor cooling due to an over charged the system. The rule of thumb is that the r134a charge is only 80% of the former r12 charge. A propperly charge r134a system should run about 18 to 23psi at the suction port with the rpm held at about 1200 with the discharge pressure under 400psi.

There are many reasons for an A/C system not to work well. Hooking up a good A/C manifold gauge set is a good place to start looking for the answers.

stope4 · 06-16-2006, 09:57 AM

I agree with above. I have a stock system, get 45 degrees at the right vent. Sounds like your system is overcharged. Bleed a little off at a time from the low side and see if cooling improves. To check you will need to raise your RPMs to about 1500 and put a thermostat in the vent. At idle cooling is a little slack.

BobbyK · 06-16-2006, 05:19 PM

If your useing the whole factory system with R134 you can tweak the POA to work better with R134.

Check out this thread in the Blazer forum
http://67-72chevytrucks.com/vboard/s...d.php?t=202734

chipflyer · 06-16-2006, 10:14 PM

I adjusted my poa valve on my stock 71 system and converted to 134, I get 42-44 out of the left hand vent. You have to adjust the poa valve if you are switching to 134 or it will not work as well.

Jeff

*rage'nrat638* · 06-17-2006, 07:45 AM

and which way would a guy adjust this poa valve. right to tighten or left to loosen ?

and how much?

thanks mark

stope4 · 06-17-2006, 09:39 AM

a stock poa is set somewhere around 29 psi at sea level. This needs to be adjusted to around 26.5 psi @msl. Best way is to get a fitting that will screw into the female end of poa. I don't know the size but it's like 1" or 1.25". This fitting needs to have a 1/4" opening so you can place the end of an air hose into it and blow air. So I guess this fitting would be 1" or 1.25"threaded male x 1/4" threaded female. At the same time hook your guages to the poa and measure pressure. Hook the guages to the two side openings on the poa one at a time until your guages read a psi. Continue adjusting screw untill guages read 26 - 26.5 psi.

By the way, you may have to take the poa to the hardware store and try fittings until you find one that fits.

see ten · 06-17-2006, 11:26 AM

Well at 11:15 it was 83* in the shade and I went out to take a reading for you fellas. It's a Vintage Air surefit system that uses 134a. I have to tell ya that looks like a solid 39* maybe 38* ........at idle sitting in the sun. We very seldom turn the fan speed to high.

Zonaman · 06-17-2006, 04:15 PM

I've had it as low as 37, driving at about 40 mph with an ambient of about 100, very low humidity. That's using an Old Air system. Too bad these old cabs aren't insulated very well! I'm working on that now.

BobbyK · 06-17-2006, 04:28 PM

Quote:

I have to tell ya that looks like a solid 39* maybe 38* ........at idle sitting in the sun. We very seldom turn the fan speed to high..

You'll get lower vent temps with the fan speed on low.
But that is nice and cold!

PanelDeland · 06-17-2006, 07:34 PM

If I can't turn the cab into a meatlocker on the hiway somethings wrong with the AC.Usually carry a blanky for the wife.I don't have AC in the panel yet but will probably use a regular Old Air or Other Pick-up unit with a street rod unit added in the rear.The tech guys I have asked seem to think one compressor will run both.

06-15-2006, 11:24 PM	#1
rage'nrat638 Account Suspended Join Date: Mar 2003 Location: THE FALL GUY CHICAGO IL Posts: 5,883	how cold does you a/c blow ? mine with the stock system except a sanden 134r compressor max's out at 60 deg's any body else got a better temp using 134r? Last edited by rage'nrat638; 07-12-2007 at 07:03 AM.

06-15-2006, 11:25 PM	#2
kansas city cheyenne Rebuilding 1 at a time Join Date: May 2006 Location: kansas city, mo Posts: 80	Re: how cold does you a/c blow ? Just depends how fast I am going and how many windows I have down. HA HA __________________ 71 cheyenne lwb 383 stroker 2004R tranny Factory ps, pb, air http://smg.photobucket.com/albums/v3...t=101_0059.jpg 66 Nova SS L-79 327 m21 http://smg.photobucket.com/albums/v3...t=101_0042.jpg

06-16-2006, 12:37 AM	#4
Ricks1971 Senior Member Join Date: Mar 2006 Location: Clarkrange Tennessee Posts: 1,787	Re: how cold does you a/c blow ? It should get colder that? I think my 72 was getting 47 degrees out of the vent when I recharged. Thats with 134r

06-16-2006, 12:48 AM	#5
220mph Speed Limits...yeh right Join Date: Jun 2006 Location: So Cal Posts: 72	Re: how cold does you a/c blow ? 39f with an outside temp of 78f __________________ 1972 3/4 ton 4x4 LONG BED 1940 Chevy Pickup 1970 El Camino Pro Street 496BB w/NOS

06-16-2006, 12:49 AM	#6
220mph Speed Limits...yeh right Join Date: Jun 2006 Location: So Cal Posts: 72	Re: how cold does you a/c blow ? If I want it really cold, I'll take my mother-in-law for a ride __________________ 1972 3/4 ton 4x4 LONG BED 1940 Chevy Pickup 1970 El Camino Pro Street 496BB w/NOS

06-16-2006, 03:51 AM	#8
ERASER5 Registered User Join Date: Jun 2006 Location: Indiana Posts: 4,859	Re: how cold does you a/c blow ? Who charged the system? How much r134a charge was used? Was the system flushed before the new compressor was mounted? How much oil was put in? Was the expansion valve replaced? How about the reciever/dryer? All of these will affect performance. A common mistake is to look up the propper r12 charge for that system and charge the same amount of r134a. The result is poor cooling due to an over charged the system. The rule of thumb is that the r134a charge is only 80% of the former r12 charge. A propperly charge r134a system should run about 18 to 23psi at the suction port with the rpm held at about 1200 with the discharge pressure under 400psi. There are many reasons for an A/C system not to work well. Hooking up a good A/C manifold gauge set is a good place to start looking for the answers.

06-16-2006, 09:57 AM	#9
stope4 Registered User Join Date: Jan 2006 Location: Houston Posts: 434	Re: how cold does you a/c blow ? I agree with above. I have a stock system, get 45 degrees at the right vent. Sounds like your system is overcharged. Bleed a little off at a time from the low side and see if cooling improves. To check you will need to raise your RPMs to about 1500 and put a thermostat in the vent. At idle cooling is a little slack. Last edited by stope4; 06-16-2006 at 09:58 AM.

06-16-2006, 05:19 PM	#10
BobbyK Registered User Join Date: May 2000 Location: Petrolia,Ontario,Canada but working in Port Huron,Mi. Posts: 1,771	Re: how cold does you a/c blow ? If your useing the whole factory system with R134 you can tweak the POA to work better with R134. Check out this thread in the Blazer forum http://67-72chevytrucks.com/vboard/s...d.php?t=202734 __________________ 71 blazer,350SBC,approx.375HP,700R4,factory GM TPI.Dual electric fans,33x12.5x15 ATR on stock suspension. Petrolia,Ontario,Canada but working in Port Huron,MI. See ALL my Blazer pic's HERE

06-16-2006, 10:14 PM	#11
chipflyer Registered User Join Date: May 2004 Location: Topeka, Ks Posts: 2,293	Re: how cold does you a/c blow ? I adjusted my poa valve on my stock 71 system and converted to 134, I get 42-44 out of the left hand vent. You have to adjust the poa valve if you are switching to 134 or it will not work as well. Jeff __________________ I'm not a pessimist, I'm just optimistic that bad things are going to happen. 1971 Cheyenne Super K10 - tilt, cruise, air, am/fm, tow hooks, factory buckets! 1986 Jeep J10 pickup, - 5.3L Vortec with 4L60e and NP241.

06-17-2006, 07:45 AM	#12
rage'nrat638 Account Suspended Join Date: Mar 2003 Location: THE FALL GUY CHICAGO IL Posts: 5,883	Re: how cold does you a/c blow ? and which way would a guy adjust this poa valve. right to tighten or left to loosen ? and how much? thanks mark

06-17-2006, 09:39 AM	#13
stope4 Registered User Join Date: Jan 2006 Location: Houston Posts: 434	Re: how cold does you a/c blow ? a stock poa is set somewhere around 29 psi at sea level. This needs to be adjusted to around 26.5 psi @msl. Best way is to get a fitting that will screw into the female end of poa. I don't know the size but it's like 1" or 1.25". This fitting needs to have a 1/4" opening so you can place the end of an air hose into it and blow air. So I guess this fitting would be 1" or 1.25"threaded male x 1/4" threaded female. At the same time hook your guages to the poa and measure pressure. Hook the guages to the two side openings on the poa one at a time until your guages read a psi. Continue adjusting screw untill guages read 26 - 26.5 psi. By the way, you may have to take the poa to the hardware store and try fittings until you find one that fits.

06-17-2006, 11:26 AM	#14
see ten WTB this ad Join Date: Sep 2004 Location: Lafayette Georgia Posts: 5,074	Re: how cold does you a/c blow ? Well at 11:15 it was 83* in the shade and I went out to take a reading for you fellas. It's a Vintage Air surefit system that uses 134a. I have to tell ya that looks like a solid 39* maybe 38* ........at idle sitting in the sun. We very seldom turn the fan speed to high.

06-17-2006, 04:15 PM	#15
Zonaman Registered User Join Date: May 2004 Location: Chandler, AZ Posts: 519	Re: how cold does you a/c blow ? I've had it as low as 37, driving at about 40 mph with an ambient of about 100, very low humidity. That's using an Old Air system. Too bad these old cabs aren't insulated very well! I'm working on that now. __________________ 69 C-10 LWB, 350, 700r4, 3.73 posi-traction, front disc brakes. Built for the desert- She can take the heat! Vivat Rex Chevus!

06-17-2006, 07:34 PM	#17
PanelDeland I am a Referee of life. Join Date: Jun 2000 Location: Greensboro N.C. Posts: 13,993	Re: how cold does you a/c blow ? If I can't turn the cab into a meatlocker on the hiway somethings wrong with the AC.Usually carry a blanky for the wife.I don't have AC in the panel yet but will probably use a regular Old Air or Other Pick-up unit with a street rod unit added in the rear.The tech guys I have asked seem to think one compressor will run both. __________________ The 47-present Chevrolet and GMC Truck Message Board Network,it's owners,moderators,members,and associates of any type should not be held responsible for my opinion. You can't fix stupid,not even with duct tape. "My appearance is due to the fact that "GOD" does punish you for having too much fun!" Barrett-Jackson has perfected alchemy,they make rust into gold! "You can lead a horse to water but you can't saddle a duck" "Cleverly disguised as a 'Responsible Adult' "Sometimes your Knight in shining armor is just a retard in tinfoil"

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