any 1966 A/C experts out there? I have replace all major engine compartment parts: I.E Rec/Dryer,condenser,compressor (3)by the way, expansion valve,muffler, hoses,water cut off valve,vacuum switch (on heater box) POA valve(came with a POA & not the Suction throttling valve> STV about $1300 if you can find one) & still can't seem to get the A/C to blow cold...(no condensation drip either)..........any educated ideas?.........thanks in advance folks.....
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Re: need C2 (1966) A/C Experts Please
What are your guage readings?? A good starting pointDick Whittington -
Re: need C2 (1966) A/C Experts Please
What are your guage readings?? A good starting pointDick WhittingtonComment
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Re: need C2 (1966) A/C Experts Please
its been a while ....readings 225 high side with 28 on the low with freeze up around the POA.... replaced the POA which I believe fixed that problem..don't recall what the final readings where but were in tolerance....still blowing around 68 degrees right after charging the system....wondering if the problem could be the evaporator??Comment
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Re: need C2 (1966) A/C Experts Please
its been a while ....readings 225 high side with 28 on the low with freeze up around the POA.... replaced the POA which I believe fixed that problem..don't recall what the final readings where but were in tolerance....still blowing around 68 degrees right after charging the system....wondering if the problem could be the evaporator??Comment
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Re: need C2 (1966) A/C Experts Please
You list of parts replaced doesn't mention the evaporator. Do you know that air flows freely through it and it's NOT plugged up with leaves & road debris that would cause makeup air to flow around rather than through it?
What I'm saying is once the engine compartment 'plumbing' is doing its thing properly, it still takes makeup air to flow properly through the evaporator to shed BTU's and arrive at the cockpit air vents COLD....Comment
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Re: need C2 (1966) A/C Experts Please
You list of parts replaced doesn't mention the evaporator. Do you know that air flows freely through it and it's NOT plugged up with leaves & road debris that would cause makeup air to flow around rather than through it?
What I'm saying is once the engine compartment 'plumbing' is doing its thing properly, it still takes makeup air to flow properly through the evaporator to shed BTU's and arrive at the cockpit air vents COLD....Comment
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Re: need C2 (1966) A/C Experts Please
Thanks Jack.....have not replaced or checked the evaporator as of yet....seems that's going to be a major job to remove.....is there a quick way to test the evaporator??Comment
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Re: need C2 (1966) A/C Experts Please
Thanks Jack.....have not replaced or checked the evaporator as of yet....seems that's going to be a major job to remove.....is there a quick way to test the evaporator??Comment
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Re: need C2 (1966) A/C Experts Please
There's two items to 'test'... First, is refigerant circulating through the evaporator and making it cool down. You know that by the observed pressure differentials on the R12 + you can physically feel the evaporator's return line.
The second is whether air flowing through the cowl is actually passing through the cooling fins of the evaporator enroute to the cockpit. Checking that out is something you typically do when you've had the whole system torn down during frame off...
But, the 'rate buster' mechanics of days past used to 'cheat' here. Instead of pulling the entire air box from the engine compartment to get inside and check things out (a LOT of labor), look for the system's 'weep hole' and work through it.
Since the evaporator collects airborne moisture, there's ususally a weep hole below the evaporator (sometimes covered with a rubber bladder) that allows water to exit when you turn the engine off. The 'rate buster' guys would pull the bladder off the weep hole and run something like a bore scope up inside the air box to actually see the condition of the evaporator's cooling fins.
Then, IF they were dirty, clogged with debris, they'd fixture a flexible tip to a shop vac and go through the weep hole to suck out the debris and get the airway free of obstruction(s) again. Now, that'll work for 'typical' debris (dead leaves, dirt, Etc.), but it won't work for every kind of obstruction you might find (dead mouse bodies, Etc.)....Comment
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Re: need C2 (1966) A/C Experts Please
There's two items to 'test'... First, is refigerant circulating through the evaporator and making it cool down. You know that by the observed pressure differentials on the R12 + you can physically feel the evaporator's return line.
The second is whether air flowing through the cowl is actually passing through the cooling fins of the evaporator enroute to the cockpit. Checking that out is something you typically do when you've had the whole system torn down during frame off...
But, the 'rate buster' mechanics of days past used to 'cheat' here. Instead of pulling the entire air box from the engine compartment to get inside and check things out (a LOT of labor), look for the system's 'weep hole' and work through it.
Since the evaporator collects airborne moisture, there's ususally a weep hole below the evaporator (sometimes covered with a rubber bladder) that allows water to exit when you turn the engine off. The 'rate buster' guys would pull the bladder off the weep hole and run something like a bore scope up inside the air box to actually see the condition of the evaporator's cooling fins.
Then, IF they were dirty, clogged with debris, they'd fixture a flexible tip to a shop vac and go through the weep hole to suck out the debris and get the airway free of obstruction(s) again. Now, that'll work for 'typical' debris (dead leaves, dirt, Etc.), but it won't work for every kind of obstruction you might find (dead mouse bodies, Etc.)....Comment
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Re: need C2 (1966) A/C Experts Please
Bob:
Make sure that the COOL-IN/HOT-PULL knob is fully pushed in and that the brass water valve for the coolant to the heater is closed and does not let hot coolant flow through the heater core. If this control knob is not set/operating properly, it could allow hot air from the heater to mix with the cool air from the the evaporator. This knob controls both the brass water valve (through a vacuum switch) and a door inside the AC/heater box.
Check both the inlet and outlet hoses to the heater to verify that this valve is closed and is not leaking through. These hoses should remain cool. If there is any doubt, you should disconnect and plug these (two) hoses as a test to eliminate this possibility.
The Chevrolet Chassis Service Manual has an excellent section on the operation and troubleshooting of the Corvette air conditioning and heating system. You need to purchase if you do not already have one.
LarryComment
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Re: need C2 (1966) A/C Experts Please
Bob:
Make sure that the COOL-IN/HOT-PULL knob is fully pushed in and that the brass water valve for the coolant to the heater is closed and does not let hot coolant flow through the heater core. If this control knob is not set/operating properly, it could allow hot air from the heater to mix with the cool air from the the evaporator. This knob controls both the brass water valve (through a vacuum switch) and a door inside the AC/heater box.
Check both the inlet and outlet hoses to the heater to verify that this valve is closed and is not leaking through. These hoses should remain cool. If there is any doubt, you should disconnect and plug these (two) hoses as a test to eliminate this possibility.
The Chevrolet Chassis Service Manual has an excellent section on the operation and troubleshooting of the Corvette air conditioning and heating system. You need to purchase if you do not already have one.
LarryComment
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Re: need C2 (1966) A/C Experts Please
Hey, just the obvious here,
are you running R12 or 134a? (synthetic R12 is fine) Either way, if you've added any oil to the system, or even a can of charged leak detect, the oil may have been crossed. If you mix reg 12 oil & 134 together (mineral & non mineral), it makes a gooey mixture that wreaks havoc on any a/c system. Your oil bottle will say if it's for 12 or 134. If it says compatable with both, that doesn't mean it can be mixed with existing system oil. Also, make sure your POA wasn't upgraded to a cycling clutch system. Some places offer the POA, but it's setup for a cycling system for better efficiency. The only other thing I could suggest is if the hoses are hooked up where they should be, I've seen the hose clamped hoses reversed.Comment
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Re: need C2 (1966) A/C Experts Please
Hey, just the obvious here,
are you running R12 or 134a? (synthetic R12 is fine) Either way, if you've added any oil to the system, or even a can of charged leak detect, the oil may have been crossed. If you mix reg 12 oil & 134 together (mineral & non mineral), it makes a gooey mixture that wreaks havoc on any a/c system. Your oil bottle will say if it's for 12 or 134. If it says compatable with both, that doesn't mean it can be mixed with existing system oil. Also, make sure your POA wasn't upgraded to a cycling clutch system. Some places offer the POA, but it's setup for a cycling system for better efficiency. The only other thing I could suggest is if the hoses are hooked up where they should be, I've seen the hose clamped hoses reversed.Comment
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