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AC compressor issues - '95 Chevy K1500 with 350

AJMBLAZER

AJMBLAZER

Better to be lucky than good.
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My buddy has a '95 K1500 with a 350. Last year of the TBI fuel injection setup. Right now the AC works okay but is a bit weak. However the main issue is that the AC compressor is cycling on and off intermittently. It will stop once in a while but not for long.

There's a bunch of metallic dust around that area so I figure the bearing in the clutch is toast. Probably the whole thing too?

Also, what years can we get a compressor off of and are they standardized or do they vary by engine and vehicle types?
Is there an official name for whatever model of compressor this is?
 
No. Don't have any.

I'm thinking it is low but the metallic dust all over it worries me.
 
Ok. I will upload A diagram of the control circuit here in a minute, but, basically, with the belt off and no power to it you should be able to free wheel it and see it change, with power and ground to it, you should have to spin the whole compressor. As they get older the magnets tend to get weak and allow slippage. its a fair bet that is what is happening, if it isn't a problem with the control relay.

From the looks of all data, the compressor is commanded on at all times when the AC is running

"The Compressor for the Air Conditioning System is driven by the engine by means of a belt drive and the A/C Compressor Clutch. The Clutch allows the Compressor to be disengaged when Air Conditioning is not required.

When the Ignition Switch is in RUN, battery voltage is supplied to the Heater and A/C Control Module through CKT 141 and the A/C Compressor Clutch Relay by means of CKT 1240, Low Pressure Cutout Switch, and CKT 603. With A/C "ON" requested, the Heater and A/C Control Module supplies voltage to coil of the A/C Compressor Clutch Relay and grounds through CKT 150. The relay switch closes sending power through CKT 203, the A/C High Pressure Cutout Switch, and CKT 59 to the A/C Compressor Clutch. The coil is then energized by grounding through CKT 150 and engages the clutch.

The A/C Compressor Clutch Diode is connected across the terminals of the A/C Compressor Clutch. Whenever the clutch is de-energized, the magnetic field around it collapses, generating and induced voltage in the clutch coil. The Diode provides a path for the current resulting from the induced voltage so that other circuit components are not damaged."

Basically it should run all the time unless its over pressure.

95 compressor relay.gif
 
Sorry, I was interrupted by a class coming in, now, if it cycles on off rapidly it could be a coolant charge issue. It looks like there are 3 different types of compressors it could be, V5 -HD6/HR6-HE HR100T/HR110MD. I spoke with the AC teacher here at the school, and he would be suspicious of the compressor because of the shavings as well. And yes I Have my EPA 609.

95 compressor wiring.gif
 
Cool. Thanks man.

It does the on/off/on... thing all the time whether AC is on or not. The AC does blow somewhat cool though.


So...with the shavings...completely new compressor or can we get away with the clutch?


Then again for what I see them going for a new compressor isn't a lot more than just a clutch setup.
 
I would go with the complete unit instead of taking a risk of the 15 year old compressor having an issue, BUT get the system checked for content before hand. air+r134a+oil=Sludge and adding a new compressor to a sludgy system will spell a quick end to the new compressor, not to mention a the money wasted on the new refrigerant to add to the system.

If your looking to do it your self, have it tested for content, if the system is still sealed, you can illegally vent it or have the coolant recycled by a shop, having them put it in vacuum. Then quickly change the compressor, and using a vacuum pump pull it into a good hard vacuum for a minimum of half an hour, longer is better for removing contaminants (water, sludge, air, old oil). If the system holds in vacuum, your good, no leaks, and you can take it to a shop to have r134a and oil put in.

You can also do it with gauges and a 20 lb tank, but if you mess up you can over/under charge the system, or blow up the tank and do bad bad things to yourself

Edit- forgot to mention, if there is air in the system you have a leak somewhere, if you can find it visually great (usually at the condenser), the other 2 options are to have a test charge put in with dye in it, and find the leak with a UV light, or put it into a vacuum and listen for the hiss.
 
Hahahaha. I think he may end up going with an AC Delete setup but man, did I mention I hate AC?

I love it when it works but I hate working on it.
 
lol Good money in it if you get it. If I get the chance I will do side work, but I don't want to screw around with charging using a tank and scale and gauges.
 
I can see why.

I'm going to talk to him tomorrow and see if he wants to go the $30-but-no-AC route or the full on repair route.
 
remember to mention to him that r134a isn't cheap. the under 2 lbs of coolant will probably cost him atleast 50 bucks, probably more, we get charges a dollar an ounce at school, and that about half price from what the instructor said
 
Oooooof. I think I know where this is headed.
 
if he wants to do it right, he can change the R4 compressor to a newer Sanden style, which is what I did. It's more efficient, quieter, and more durable from what I understand. But, if he's looking for the cheap way out, the A/C delete bracket/pulley is right up his alley.
 
I talked to him today and we'll be putting a delete pulley on it most likely. Too many things he needs to do otherwise to put at a minimum several hundred bucks into the AC system.

So speaking of that...does it take a standard AC belt with the AC delete pulley?
 
pretty sure the delete pulley is slightly smaller in diameter, needing a shorter belt. look up a non -A/C belt for that year. Compare to one for A/C. GM used the bypass in NON A/C vehicles from the factory.
 
I think we are going to install the Dorman Help! AC delete setup. Not sure if that's the same or not.
 
I used the one from rock auto, Same belt and everything, to use a non ac belt you have to route it the other way
 
Okay. I have no idea if he needs a new belt or not anyway. Thanks.
 
Why not just leave it alone, as long as the compressor isn't running, it's not hurting anything anyways, the pulley is just freewheeling.

I haven't had AC in my Burb for most of the 10 years I have owned it, never took the compressor off.
 
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