Heater problem

[Tleg93]

I have two questions: First, why would my heater be stuck with the heat turned all the way up even if I have it set to blow cold air. Two, can I cut the belt that drives the air compressor in my 1991 SS? It looks like the compressor is driven by the cam and I'm guessing it can be cut off but I just wanted to ask you guys first.

[vrg3]

I think there's a cable that operates the valve that controls how much air goes through the heater core. Maybe the cable's unhooked from the lever or the other end, or otherwise binding?

The A/C compressor belt is driven off the crankshaft pulley. If you look closely at it again you'll see -- the crank pulley is really two pulleys. One drives the alternator and power steering and the other drives the compressor. You can safely cut or remove this belt.

Why? Is your compressor clutch seized up?

[Tleg93]

No, it's not frozen, it's just making a lot of noise. Someone told me that R134 has a lubricant in it that lubes the bearings in the compressor. My system has been running on empty for quite a while and it seems like the now loud noise is coming from the compressor. I looked at it a bit and stopped short of cutting it. I realize I could have looked this info up in my Haines manual but I couldn't find it right away so I just thought I'd ask.

[vrg3]

Yes, the refrigerant does carry the compressor's lubricant, and so insufficient refrigerant can kill the compressor.

But if your compressor clutch is still working you might just want to remove the four black A/C relays from the underhood fuse box. Or just disconnect the compressor clutch's connector (although that leaves the connector exposed to the elements).

I ran with those four relays pulled for a long, long time before I fixed my A/C.

[Tleg93]

Ah, I see, thanks. The noise is bugging the heck out of me. Will pulling the relays quiet the noise? It doesn't seem like it would to me.

[vrg3]

It depends on whether the noise is coming from the clutch or the compressor itself.

If the noise only happens when the compressor is turned on (i.e. in A/C, MAX A/C, DEF, and DEF/HEAT modes), then the problem's the compressor, and pulling the relays will stop the noise.

If the noise happens all the time, then it's the clutch, and you'll have to remove the belt. You might still want to pull the relays also just so the clutch quits engaging though.

[Brat4by4]

My a/c system is also empty right now. Is it a good idea to pull those fuses to save the compressor? I was wondering whether it would burn out or start knocking without any refrigerant in it.

[vrg3]

If the system's empty, the pressure switch mounted on the receiver/drier should keep the compressor clutch from engaging. You can just look at the clutch to check whether it's engaging or not.

Running the compressor without lubrication will destroy it. Running it without refrigerant will cause it to run out of lubrication (since the compressor will eventually spew all its oil out the discharge port). But that's one reason the pressure switch is there -- to prevent that from happening.

It couldn't hurt to pull the relays anyway.

[LaureltheQueen]

i dont know anything about AC, so i'll do what I can to help with the AC issue. there's a cable that attaches to your HVAC module, (which can be removed by taking out your cupholder, radio surround, and black plastic piece that wraps around your guage cluster and whatnot), it runs down through your dash, attached at various places with clips(those need to be hooked for it to work correctly(i think there's 2) the other end is attached near the bottom left corner of your glovebox, a bit farther back. that pulls the heater flap forward and back, it's affixed to the heater thing)i'm so technical) with a screw with an attached washer. You could probably set the flap on it's own to a comfortable setting if the cable is broken or something, and just leave it there until you have a chance to get to a junkyard to fix it.