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A/C recharge with enviro-safe (Read 4069 times)
Jul 12th, 2013 at 1:04pm

737fixer   Offline
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My tired old 75 L48 airconditioning system was not working well when I got her last year, this year it hasn't worked at all, just blows hot air.  I finally bought some envoi-safe 12a refrigerant from a guy at work who had bought a case and recharged his Chevelle with good results.
The can tap is a 134 style and the A/C system took an R12 hose so I bought a hose with a 134 end to go on the can tap and a r12 end to hook to the car.  I used about 2 to 2.5 cans and she's blowing cool, not cold but cool (it's 98F here in Houston today).  I didn't have a pressure gauge so I figured I shouldn't put much more in.   I think I will put a valve in the heater core line tomarrow to shut off water flow to the core and see if that helps cool it down a bit more.

Have any of you guys used Enviro-safe in your cars?  Anyone installed a water shut off valve??
John
 

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Reply #1 - Jul 12th, 2013 at 1:22pm

68-73-77   Offline
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A shut off valve is almost a must on these cars if you have the OEM heater & it works. Just get a good one, hook it up to the water pump side so you don't have the pressure on your heater core all the time. & open it every once & awhile to let the water circulate. I might try that eviro-safe R-12 in the 77.
Alan Smiley
 
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Reply #2 - Jul 12th, 2013 at 5:27pm

wnmech   Offline
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I had in the past expirmented with the R-12 substitute known as  freeze 12.  To me it is somewhat the same as the R-134 that runs with higher pressures with the same cooling capacity the only difference is that it is a direct added replacement for good old R12.  Like Alan mentioned you should have a heater core cut off lever.   That will help.  An electric fan will help move air thru the condenser at lower speeds.  I was buying my R12 on craigslist up here in the DFW area for sometimes as low as $10 a can.  These corvettes have never been great air conditioned cars and if I were you I would go back to the real thing.  The demand for the R12 is not much any more in my opinion.
Rick
 
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Reply #3 - Jul 13th, 2013 at 8:31am

737fixer   Offline
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Has anyone ever installed a better fan/blower?  Mine seems to work ok but sure doesn't put out the volume of air a more modern car does....
John
 

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Reply #4 - Jul 13th, 2013 at 8:36am

Artsvettes   Offline
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New Jersey

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I used an s10 blazer blower motor in my 73 but you need to make a 1 inch spacer to mount it to your evap box. The fan is larger so it will push more air................jack
 

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Reply #5 - Jul 13th, 2013 at 11:10am

77vette   Offline
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Read a good article on the subject and plan on doing an upgrade but never seem to find the time. If you are interested here is the link to the article and the adapter.
http://www.vettemod.com/forum/showthread.php?t=1666&highlight=fan+adapter

http://www.vettemod.com/forum/downloads.php?do=file&id=51

If nothing else it could br some interesting reading

Ron
 

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Reply #6 - Jul 15th, 2013 at 8:16pm

737fixer   Offline
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Houston

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The blower upgrade is something I will be looking into soon.
I did have to change the A/C belt after it liberated itself from the engine compartment in shreds, I'm guessing it was at least 15 yrs old.  New belt works great!
Also I installed a valve in the line from the water pump to the heater core.  I started the car and let it run for 30sec or so, then shut it off and closed the valve.  I restarted the car and within a few minutes the temp got up to 230+ (it never gets above 190).  Not sure what happened, I opened the valve about 30 min later and ran it.  The temp went to 190 and stayed there.  Anyone ever heard of a car overheating from a valve in the heater line????  A friend had the same problem with his Chevelle...
John
 

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Reply #7 - Jul 16th, 2013 at 3:52am

77vette   Offline
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Never had that issue, with the valve all you are doing is blocking the hot water from reaching the heater core while allowing it to continue to flow and cool the engine. It shouldn't matter which heater hose you install it on. Hopefully someone else will chime in soon

Ron
 

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Reply #8 - Jul 16th, 2013 at 4:13am

Artsvettes   Offline
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Never heard of that happening..............jack
 

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Reply #9 - Jul 16th, 2013 at 5:05am

68-73-77   Offline
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It doesn't really matter which side the valve is on it's just that on the water pump side you are blocking the constant water pressure on the heater core & there can be lots of pressure depending on the pump & engine RPM"S. Like the 73 I think Jack put in a high volume water pump & it has tons of pressure.    Apparently your heater core is acting like a radiator & helping cool the engine. How much antifreeze are you using? Should be around 25% for efficient cooling. & put in 1 or 2 bottles of water wetter. Get an inexpensive laser temp gun & get some accurate readings on your thermostat housing & upper & radiator inlet & outlet. This will give you an idea if your radiator is working properly. You can track it down as these cars are famous for overheating problems.  When I got my 68 it used to run 220+ at idle & over the yrs I've managed to get it down to 174 degrees on the hottest day. It's also like ever little thing makes it a little better.
Alan Smiley
 
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Reply #10 - Jul 22nd, 2013 at 7:07am

737fixer   Offline
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The rain finally stopped here in Houston, I was able to get the shut off valve to work without overheating.  I ran the car with the valve open, topped off the antifreeze then ran it again.  I closed the valve and no more overheating.  All I can think of is there was some air in the system from installing the valve, causing the overheating.  All is good now Smiley
Thanks for all the advice and info!
John
 

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Reply #11 - Jul 22nd, 2013 at 2:36pm

TX 73 gone   Offline
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The C4 fan is the way to go. supposed to be a lot better than OEM. You can make a spacer out of wood. vette mod has a printable diagram for one. I was going to paste the link but couldn't find it. gotta love that Houstom weather. tripple digits are just around the corner.

Charlie
 

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Reply #12 - Sep 21st, 2018 at 9:29pm

slim   Offline
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My 1979 has a vacuum actuated hot water shut-off valve, factory stock... If your system works as designed, when the heat control lever is moved to "Cold", the heater duct door closes, and vacuum to the hot water valve shuts off the flow of hot water to the heater core. Roll Eyes
 
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