C2 A/C question

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Aug 6, 2007 | 07:06 PM

R6T7

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Racer

Joined: Sep 2004

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From: La Quinta CA

C2 A/C question

I'm trying to troubleshoot my factory 66 A/C system - the compressor appears to be working well - the suction fitting is ice cold after it has been running for a few minutes - but the air coming form the vents is warm. How do I figure out what's wrong?

Bob

Aug 6, 2007 | 07:16 PM

Donald #31176

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From: Maryland

On 63-66 factory AC there is a brass vacuum valve screwed to the top of the heater box. With the AC on this valve is suppose to prevent hot water from entering the
heater core. If the valve is defective hot water will flow thru the heater core all the time.

Aug 6, 2007 | 07:25 PM

R6T7

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Racer

Joined: Sep 2004

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From: La Quinta CA

Quote:

Originally Posted by Donald #31176

Thanks, I'll check that - but I don't think that water is flowing through the heater core - the air coming throught the A/C vents isn't hot, it's just not cold - or could the heater be offsetting the A/C???

Bob

Aug 6, 2007 | 08:23 PM

67vetteal

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From: Riverhead New York

Quote:

Originally Posted by bobbeh

Hi Bob, I don't know the year of your A/C car so I'll run on a little bit. 63-66 have a STV, Suction Throttling Valve located on the Heater Box and is most likely Ice Cold because it is Frozen solid and not working. Same thing for 67-7?, but they use a POA valve. Both STV and POA regulate the amount of Freon that is allowed to Evaporate to dissipate the Heat inside your cars Cabin. Please give us a little more info such as what did you charge the system with? How many pounds are in play? Lots of info at the following link: ACForum.com http://www.autoacforum.com/messagevi...&threadid=6974 Al W.

Last edited by 67vetteal; Aug 6, 2007 at 08:26 PM. Reason: More Information

Aug 6, 2007 | 08:54 PM

R6T7

Thread Starter

Racer

Joined: Sep 2004

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From: La Quinta CA

Quote:

Originally Posted by 67vetteal

Hi Al -

This is an unrestored 72,000 mile 66 coupe with a totally original A/C sytem. It is running a charge of 3 lbs of R12. I recently had the system flushed, and found that the STV valve was leaking. I managed to find a used replacement and installed it along with a new reciever dryer. After recharging the system, it seems to be holding the charge very well, but after turnng the A/C on it blows warm air even though the compressor is cold at the suction side. The evaporator side is cold also. I'm thinking there's a damper door or a diverter that needs to be opening or closing to let cold air flow, but I don't know how to test it.

Regards,

Bob

Aug 6, 2007 | 09:35 PM

67vetteal

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From: Riverhead New York

Bob, Is the STV showing Frost from top to bottom? If so it's Frozen and needs to be serviced. The Air Flow Director on these cars is controlled by pulling out the A/C **** which as I remember, activates the Compressor and redirects the Air Box inside the car. With the car off you should be able to Hear the Flapper move when you pull the **** out. Al W.

Here's more from the ACForum. http://www.autoacforum.com/messagevi...&threadid=6899

Aug 7, 2007 | 01:11 PM

R6T7

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Racer

Joined: Sep 2004

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From: La Quinta CA

Quote:

Originally Posted by 67vetteal

Here's more from the ACForum. http://www.autoacforum.com/messagevi...&threadid=6899

Al -

No, the STV is not frozen - it's cold, but no frost. I'll check the air door -

Bob

Aug 14, 2007 | 09:19 PM

R6T7

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Racer

Joined: Sep 2004

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From: La Quinta CA

I have checked the air door - it is clearly opening and closing when the Air **** is pulled out. The suction side of the compressor is cold as is the STV valve (not frozen), but the line from the evaporator is not cold. This would seem to indicate that the STV is not allowing refrigerant through the evaporator. Is there an adjustment for this? I'm not sure how to troubleshoot this problem!!

Bob