You can get a junkyard compressor just for the coil.
A/C Compressor Field Coil
- Thread starter cpayne5
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After kc8adu's post above (thanks!), I did some reading and came came to the conclusion that the coil had to have a thermal fuse in it.
I went and got the old one and started chipping away at the material that protects the copper wire. There was a lump that I figured had to be the fuse so I started chipping away in that area...and there she was.
Inserting a jumper across the fuse "fixes" the coil. 3.8ohms
So, apparently there's a lot of heat there. Either friction/slipping of the clutch or voltage issues feeding the coil. I have tomorrow off so I'll spend some time out in the garage trying to figure it out.
I went and got the old one and started chipping away at the material that protects the copper wire. There was a lump that I figured had to be the fuse so I started chipping away in that area...and there she was.
Inserting a jumper across the fuse "fixes" the coil. 3.8ohms
So, apparently there's a lot of heat there. Either friction/slipping of the clutch or voltage issues feeding the coil. I have tomorrow off so I'll spend some time out in the garage trying to figure it out.
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I wonder if that's just a defective thermal fuse or a causality of something else. You mentioned voltage drop can cause this so that whats got me thinking about this relay.
Originally Posted By: cpayne5
Originally Posted By: zzyzzx
You can get a junkyard compressor just for the coil.
Used compressor at local yards are $225+
That's way more expensive than even a new compressor for any of my cars. Have you tried online junkyards (I.E. - eBay)?
Originally Posted By: zzyzzx
You can get a junkyard compressor just for the coil.
Used compressor at local yards are $225+
That's way more expensive than even a new compressor for any of my cars. Have you tried online junkyards (I.E. - eBay)?
Originally Posted By: Trav
I wonder if that's just a defective thermal fuse.
Unlikely.
Excellent pic though!
Anyway, I would be looking through the rest of the circuit for any issues. If it works like my car, you should be able to apply 12V to the coil independently to test the coil.
It's mid-October, do you really need A/C?
I wonder if that's just a defective thermal fuse.
Unlikely.
Excellent pic though!
Anyway, I would be looking through the rest of the circuit for any issues. If it works like my car, you should be able to apply 12V to the coil independently to test the coil.
It's mid-October, do you really need A/C?
I had a eureka moment today when this topic popped to the forefront of my thoughts...
the coil will create a large induction currrent whenthe power get's switched off, with the opposite polarity of the feed.
The circuit will have some way to bleed off this induction current, either a diode or an axtra resistor between power and ground. If you have the electrical manual, check there where it is. Ususally it's part of the switching relay though. If you found it, check the diode or resistor are still ok.
the coil will create a large induction currrent whenthe power get's switched off, with the opposite polarity of the feed.
The circuit will have some way to bleed off this induction current, either a diode or an axtra resistor between power and ground. If you have the electrical manual, check there where it is. Ususally it's part of the switching relay though. If you found it, check the diode or resistor are still ok.
Look at "Unburnished Clutch" here:
http://www.ryderfleetproducts.com/examining-clutch-failures/t-1229744
Interesting. You haven't overcharged it either, have you?
What I've seen is oil leaks out of the system along with refrigerant, a user adds refrigerant only, more oil leaks out with more refrigerant, the compressor then starts demanding a lot of additional power as it gets close to seizure, and the clutch starts slipping or emitting sparks as it engages.
http://www.ryderfleetproducts.com/examining-clutch-failures/t-1229744
Interesting. You haven't overcharged it either, have you?
What I've seen is oil leaks out of the system along with refrigerant, a user adds refrigerant only, more oil leaks out with more refrigerant, the compressor then starts demanding a lot of additional power as it gets close to seizure, and the clutch starts slipping or emitting sparks as it engages.
Originally Posted By: spackard
Look at "Unburnished Clutch" here:
http://www.ryderfleetproducts.com/examining-clutch-failures/t-1229744
Interesting. You haven't overcharged it either, have you?
What I've seen is oil leaks out of the system along with refrigerant, a user adds refrigerant only, more oil leaks out with more refrigerant, the compressor then starts demanding a lot of additional power as it gets close to seizure, and the clutch starts slipping or emitting sparks as it engages.
Thanks for the link. I saw that one last night. I've been to pretty much every A/C webpage on the internet, I think. haha
It's not overcharged. I've never touched the A/C til last week. I hooked up my gauges the night it stopped working. I figured at the time that the charge had leaked to the point where the low pressure switch was restricting clutch engagement.
Look at "Unburnished Clutch" here:
http://www.ryderfleetproducts.com/examining-clutch-failures/t-1229744
Interesting. You haven't overcharged it either, have you?
What I've seen is oil leaks out of the system along with refrigerant, a user adds refrigerant only, more oil leaks out with more refrigerant, the compressor then starts demanding a lot of additional power as it gets close to seizure, and the clutch starts slipping or emitting sparks as it engages.
Thanks for the link. I saw that one last night. I've been to pretty much every A/C webpage on the internet, I think. haha
It's not overcharged. I've never touched the A/C til last week. I hooked up my gauges the night it stopped working. I figured at the time that the charge had leaked to the point where the low pressure switch was restricting clutch engagement.
I think this is all heat related due to clutch wear. I removed the new coil today and really looked over the clutch pulley face and armature plate.
The plate has worn down into the face of the pulley. It is deep enough to where you can't use feeler gauges to accurately measure the gap. So, when I shimmed it and set the gap when installing the new coil, it must have been way off. I'm guessing normal wear caused the gap that fried the original coil.
I made a run to Radio Shack this morning and bought a new 139*C thermal fuse. I just put it in the new coil. It tests at 3.9 ohms, same as when new. I used a bench grinder to remove the plastic off of red butt connectors and used those to attach the new fuse.
I have since coated the exposed components with high temp red RTV. I'm going to let it dry for 24 hours, reinstall, and hope for the best. Not sure how I'm going to shim the clutch. By feel, I guess. Worth a shot.
If this fails miserably, I'm probably going to buy a new/reman compressor off eBay to harvest parts from. Unless anyone knows where I can find an aftermarket clutch?
A/C is nice in the winter for defogging purposes. It was during a heavy rain two weeks ago when I noticed the A/C was out. My son and I were driving and the windows were fogging up more than usual.
The plate has worn down into the face of the pulley. It is deep enough to where you can't use feeler gauges to accurately measure the gap. So, when I shimmed it and set the gap when installing the new coil, it must have been way off. I'm guessing normal wear caused the gap that fried the original coil.
I made a run to Radio Shack this morning and bought a new 139*C thermal fuse. I just put it in the new coil. It tests at 3.9 ohms, same as when new. I used a bench grinder to remove the plastic off of red butt connectors and used those to attach the new fuse.
I have since coated the exposed components with high temp red RTV. I'm going to let it dry for 24 hours, reinstall, and hope for the best. Not sure how I'm going to shim the clutch. By feel, I guess. Worth a shot.
If this fails miserably, I'm probably going to buy a new/reman compressor off eBay to harvest parts from. Unless anyone knows where I can find an aftermarket clutch?
A/C is nice in the winter for defogging purposes. It was during a heavy rain two weeks ago when I noticed the A/C was out. My son and I were driving and the windows were fogging up more than usual.
Did you check the gap and adjust? On my lawn mower the clutch coil went out. They had detailed instructions on how to set the correct gap. When the gap is too large the current really goes up and they end up burning out the coil. Probably what made the original blow.
I can probly get you a clutch kit. But its cost surpasses the cost of a brand new compressor with clutch.
Originally Posted By: cpayne5
A/C is nice in the winter for defogging purposes. It was during a heavy rain two weeks ago when I noticed the A/C was out. My son and I were driving and the windows were fogging up more than usual.
That would have happened anyway! I haven't had working A/C in one of my cars and in so far as defogging goes, I don't miss it.
A/C is nice in the winter for defogging purposes. It was during a heavy rain two weeks ago when I noticed the A/C was out. My son and I were driving and the windows were fogging up more than usual.
That would have happened anyway! I haven't had working A/C in one of my cars and in so far as defogging goes, I don't miss it.
Wire a 5w 194 light bulb in place of the coil & check voltage drops along the entire circuit from the relay out to the clutch. Check the voltage drop of ground where the compressor bolts to the engine too.
For fun I looked up some prices. A new clutch kit is $465
New compressor is $495
New compressor is $495
The silicone might be insulating the thermal switch from the heat, better than the original configuration. The original potted installation of the thermal switch probably had much better thermal conductivity. Reducing the voltage to the coil or increasing the gap will not cause it to get hotter due to DC power dissipation in the coil. Once the DC current is established it's just DC resistance. Reducing the voltage could certainly cause slippage, which will generate heat along with the approximately 40 watts being dissipated in the coil. When the current is changing (i.e. being switched on or off) you will have the effects of the inductance of the coil which will only increase the impedance of the circuit. The effect of the inductance only lasts a few milliseconds. The gap may effect the inductance of the circuit when it's turned on, only until the clutch plate is pulled in. Really its just a big solenoid.
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