1995 GMC K1500 4x4 P/U - Compressor

[tken35]

When I was running the truck earlier today, I heard a "grinding" noise from the compressor area, more specifically, the clutch ("Red"). When I touched any of the "Blue" areas the noise lessened substantially. Is this something I should be concerned about, given that I won't be using air conditioning for another 6 months? Does this mean that the compressor is shot?

[jamesslcx]

Tken35, hard to say without hearing the noise. Did this happen with the defroster on? If it does go out I believe you can replace the clutch separately.

[j cAT]

Originally Posted by tken35

When I was running the truck earlier today, I heard a "grinding" noise from the compressor area, more specifically, the clutch ("Red"). When I touched any of the "Blue" areas the noise lessened substantially. Is this something I should be concerned about, given that I won't be using air conditioning for another 6 months? Does this mean that the compressor is shot?

take the belt off and rotate the pulley . if it wobbles or makes noise the ac compressor pulley bearing is going . when it goes the pulley will lock up and the belt will smoke till it snaps.


you can purchase a ac compressor pulley replacement kit so you will not need to install another compressor. I don't think you can somehow bypass this issue with using a smaller belt and not use the compressor pulley.

[j cAT]

Originally Posted by tken35

When I was running the truck earlier today, I heard a "grinding" noise from the compressor area, more specifically, the clutch ("Red"). When I touched any of the "Blue" areas the noise lessened substantially. Is this something I should be concerned about, given that I won't be using air conditioning for another 6 months? Does this mean that the compressor is shot?

in the rust belt this old trying to replace just the pulley bearing is near impossible. scrap yard is a good alternate fix for a compressor working or not with a good pulley bearing.

[tken35]

As soon as I get a chance, I will take the belt off and see if it wobbles or makes a noise (I am betting it will ).

j cAT, I was afraid that someone was going to say that the pulley might lock up... I will head to the auto recycler as soon as I get a chance. If I wanted to test to see if the replacement compressor was working, how warm does it have to be for the compressor to work?

jamesslcx, does a compressor normally cycle on in the dead of winter when the defrost is on? Would this be an indication of a bad clutch? Btw, what is the function of the clutch?

[brcidd]

If the noise is a scrapping sound AND the front hub is not turning- this is probably a tight air gap,due to coorosion, and the clutch hub needs to be pulled out a tad. This can be done by borrowing the clutch puller tool from Autozone- the gap between the clutch driver and the pulley face should be about .020" You can do this with out removing the compressor, or discharging it. The fan shroud removed would make it much easier.

Are there small metal fragments about the clutch driver (out front) clinging to the driver due to magnetic effect? This would be positive confirmation.

[j cAT]

Originally Posted by tken35

As soon as I get a chance, I will take the belt off and see if it wobbles or makes a noise (I am betting it will ).

j cAT, I was afraid that someone was going to say that the pulley might lock up... I will head to the auto recycler as soon as I get a chance. If I wanted to test to see if the replacement compressor was working, how warm does it have to be for the compressor to work?

jamesslcx, does a compressor normally cycle on in the dead of winter when the defrost is on? Would this be an indication of a bad clutch? Btw, what is the function of the clutch?

when the pulley bearing is going the pulley wobbles this then hits the clutch ,,, scrap noise results. on old vehicles like this the clearance usually increases as the surface wears down. this causes poor cooling as slippage results.

the ac compressor when in defrost if the system gets warm enough will cycle. looking at your picture you have a lot of rust coming from the pulley bearing area.


to test out an ac system you would need 80deg f temps to get the system up to the high side pressures. need around 275-325 psi. with that then you will get good cooling..

in winter when installing give the system a good long vacuum ...then install most of the system required refrigerent, but not all..when the warm weather arrives then test and top off if required. never put too much in .

drain out the old oil of old compressor and measure it then drain out replacement compressor oil. add new oil to the replacement compressor of the same amount plus 1 oz. PAG 150 oil is used with r134 refrigerent which I am guessing the system had when new . if r12 refrigerent then you would use a conversion oil which is compatible with a system converted from r12 to r134.

buy new O rings for the compressor connections.