View Full Version : Air Conditioner 62 Coupe

07-12-2013, 12:49 AM
I have notice that the compressor (I think it's the compressor) for the air conditioner is slightly frosting up when I am driving around even though the air is not on. When I pop the hood it is perspiring and cold to the touch. Is something leaking or is this gremlin common to the these birds?

07-12-2013, 10:47 PM
I'm closing in on the problem maybe. The solenoid that cycles the compressor may be faulty leaving the air conditioner on even when the heater is on. I don't hear it cycling on and off during driving. That could be do to the engine roaring. I'm not sure at this point. Does anyone else that has air notice the frosting and dripping from the compressor that I have been talking about?

Ian M Greer
07-13-2013, 07:33 PM
Sounds like your thermostat might be faulty, keeping the clutch on the compressor energized . Now if you have your fan switch turned off the suction (return line ) the large one, will frost up to the compressor which is a sign that your slugging liquid . This is not a good situation and can damage your compressor internally . Pull the wire connection at the clutch until you can get a qualified a/c tech look at it . Ian (REMEMBER NOT ALL BIRDS FLY SOUTH )

07-13-2013, 09:32 PM
Hi Ian,

Thanks, I will look into that. Neither of the lines are frosted up, only the compressor itself. I took out the metal console last night and cleaned it. I hooked back up the fan cable and adjusted it to make sure it slides all the way to the left (off) position. I will try the car tonight to see if the air is still staying on. Behind the console is a door that is open when the air is on and closed when you switch the controls to heat or defrost. I'm not sure if the a/c shuts off at that point. With the engine running its loud and I cant tell if the compressor is still turning. I WILL POP THE HOOD AND LOOK AT IT TONIGHT.

07-15-2013, 01:39 AM
Thanks again Ian,

I will try to locate the wire going to the clutch. There were several black wires going into the back of the compressor. I will try to find a diagram showing the parts of the a/c so I can find the clutch and disconnect the right wire. Electrical is my weakest link. I will try locate a a/c expert for these cars in the Toronto area. I took the car out tonight for a short drive and put the heat on to see if this would help disengage the a/c but when I popped the hood the compressor was still cold and sweating.

07-15-2013, 09:52 AM
Is there anyone with a/c that could explain how the a/c unit functions normally and if they have observed sweating ect....

Thank you

Ian M Greer
07-15-2013, 01:01 PM
Look for the wire coming directly off of the electromagnetic clutch directly behind the pulley of the compressor . Fallow that wire and you should find a plug in that if you separate will disengage the clutch stopping the compressor. Ian (Remember Not All Birds Fly South )

07-16-2013, 12:55 AM
Thank you for the info Ian. I read the servicing and testing of the a/c in chapter 10 of the manual. I will try to see what I can do mechanically, without opening up the pressure lines of course, before taking it to a a/c mechanic. I will try to test the thermostatic switch to see if that in fact is the culprit. Also the lever that activates the a/c has a fast idle switch adjustment screw.

07-17-2013, 12:05 AM
Hi All

After observing the A/C operating for approx 10 min, the clutch is not disengaging from the compressor: no clicking sound, and it doesn't stop turning. With the car off I can turn the clutch a little but it seems to be sticking. As soon as I turn the car on the air starts up right away. The lever in the car is at the off position but I wonder if it is not totally off. The cable may need adjustment. This still would not explain the clutch not coming in out. What component affects the clutch operation directly?Could it be the thermostatic switch, is it the charge of refrigerant, Is it the expansion valve?

07-17-2013, 12:17 AM
The compressor in the car looks different from the picture in the manual. There is a cylinder like device, possible a solenoid with wires coming off it that sits on top of the compressor. I will post a picture and see if the previous owner had someone rebuild the unit and get creative. The slip ring and brushes are there and I observed some arching while I was testing a/c.

07-17-2013, 02:43 AM
If the clutch will not disengage, either it has continuous power or the clutch is defective.

Can you post a photo of the compressor and a close-up of the clutch asm?

07-17-2013, 09:45 AM
Would anyone know of a place to purchase a thermostatic switch for a 62 tbird. I believe the part # is 19618a. I found one for 175.00. I wondering if that is what I should expect to pay.

07-19-2013, 10:02 AM
What would be the simplest way to test the thermostatic switch? I have tried to look at it and there is no room to move where it is. Is there any way to test it in position or does it have to come off?

Ian M Greer
07-19-2013, 11:41 AM
If you have an Ohm meter , set it to resistance and attach it to the two terminals of the thermostat . If the thermostat is in the off position ( warmest setting -not calling for cooling) you should have no deflection of the needle . If you do have deflection then the thermostat is defective . If that checks out OK then lowly raise the setting of the thermostat by turning it in the colder direction . You should see needle deflection when you reach a point where the thermostat setting is colder than the surrounding air of the sensor bulb of the thermostat , at that point it should put 12volts to the compressor clutch . Ian(REMEMBER NOT ALL BIRDS FLY SOUTH )

07-19-2013, 11:59 AM
Thank you Ian. I will try to test it from where it is.

07-19-2013, 05:02 PM
What about the clutch bearings and the bullet connection at the clutch... Did you disconnect power? Are the bearings working freely?

Before troubleshooting the electrical, you should prove the mechanical operations first. Most A/C compressor problems are such that the clutch won't energize, not de-energize. - Dave

07-19-2013, 05:22 PM
The clutch wont de-energize. With the car off (power off) the clutch turns freely but sticks with a little friction. It may have a bearing issue but it's the not de-energizing problem that is keeping a/c on. It could be the cable to the switch adjustment but the lover that turns the switch from off to on now looks like it travels from one extreme to the other good. i don't hear the compressor cycling or the clutch disengaging.

07-19-2013, 06:05 PM
The clutch wont de-energize. With the car off (power off) the clutch turns freely but sticks with a little friction. It may have a bearing issue but it's the not de-energizing problem that is keeping a/c on...I am confused by your answer. If you have a bearing problem, the compressor bypasses the electromagnetic clutch and the belt simply turns the compressor shaft.

There is a simple way of testing this, by disconnecting the electric wire at the clutch. Understand, with no power, the clutch cannot energize and the compressor should not turn. The belt-driven pulley simply rides on the bearings but the compressor does not turn.

After disconnecting the power, tell us your results. - Dave

07-19-2013, 11:54 PM
With the power disconnected, the clutch does not turn. It is disengaged. Something I could not see happening when the power was on. The clutch would not cycle ever. When a bearing issue was suggested, I assumed that the magnetic clutch, when not engaged, will spin freely by hand because it is not magnetized and if is doesn't then it must be the bearing. It feels like it is sticking as I try to turn it by hand. When the power is on the clutch seems just to be in a constant energize situation. I guess it could be the switch or the cable that is causing the problem. Unless another member who has a/c can spin the clutch with ease when the power is off.

When the power is on, it blows very cold air. Because it seems not to be cycling, I decided, with Ian's advice to unplug it so as not to blow the compressor out. Where that thermostatic switch is though, it is hard to see it and test it. I may have to pull the front seat out. Or maybe take the dash apart.

07-20-2013, 05:43 AM
Whether you have a Warner or Eaton clutch, they have their own separate bearing (apart from the compressor bearings).

The bearing allows the pulley to spin freely as long as the clutch is NOT energized. There should be no drag:

I don't mean to beat this dead horse but again, if the bearing is frozen, the compressor will not cycle.

I'm going to believe you when you say the compressor does not turn with the clutch wire unplugged. That being true, you are right in pursuing and testing the evaporator switch. - Dave

As a side note... I don't know why they call it a clutch when it's really like a brake. Brakes are never engaged until energized. Clutches are always engaged until energized.