how cold does you a/c blow ?

[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?

[kansas city cheyenne]

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

[Ricks1971]

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

[220mph]

39f with an outside temp of 78f

[220mph]

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

[89 crew]

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]

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]

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]

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]

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]

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

and how much? thanks mark

[stope4]

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]

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.

[64fleetside]

we got 39* air consistently w/my bro's 69, we used 1990 C10 serp belt setup w/R4 comp, Old Air POA eliminator & Old Air two electric fan setup, stock GM everthing else. Some tinkering & fiddling w/charge was neccessary. Rage you need more airflow thru rad or less freon. brian

[subtle71]

Originally Posted by see ten

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.

Ditto! Sounds like I have the exact same system as see ten. I bought mine back in 2000. It was installed in 2001 and is still blowing a 38 degrees. This fat southern fella loves his cold Vintage Air surefit system and highly recommend it!

[Zonaman]

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]

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]

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.

[FRENCHBLUE72]

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..