A/C making a hell of a ruckus

Jibbles8 · August 26, 2019

So my 89 G20 conversion van Mark 3 has been having some HVAC problems. When the a/c is turned on the engine sounds like hell while idling in P, D, R, and N, yet it goes back to that good 'ol Chevy hum when I turn it to vent or heat. I've been through, pretty much, the whole system. Except for messing with the rear condenser, but cleaned and reinstalled the rear blower motor and it works great......but, after I recharged the system with r-134a, replaced the blower motor resistor, relay, cleaned out the ducting as best I could, the mode selector switch, and the fan speed switch (which when the switch is on hi the motor blows a M1 or M2??) And replaced the tensioner pulley bearing....the ruckus is still there, sounds like too much of a load is being put on the engine......I'm thinking it's the clutch/pulley bearing (but that spins like butter, test done with serp belt removed) or the clutch itself?!? Can anybody help a fellow DIYer out?

davester · August 26, 2019

could be the clutch, or could be the pump itself. With my parents Cadillac, the pump seized, and the thing would make a racket ever time the clutch engaged.

Can you rotate the center part of the pulley (it doesn't spin with the engine when the a/c clutch is disengaged, but does spin when it is engaged) by hand (obviously, only do this with the engine off).

Jibbles8 · August 26, 2019

I'll update tomorrow with info, it's a bit late here to be wrenching right now....but if the compressor shaft?/center part of the pulley does like you've stated, would that mean the clutch?

davester · August 26, 2019

If the center part doesn't rotate, then the pump is bad, and likely the clutch is also bad from being engaged in this condition. Sparks were flying when it happened with the Cadillac.

If it were just the clutch (as in, you can rotate the center part by hand with the engine off), then with the engine running and you engage the a/c, you would likely see that the center part doesn't rotate very fast (or at all), but you can hear the racket.

Jibbles8 · August 26, 2019

Thanks, I'll update in the morning

Jibbles8 · August 27, 2019

So the clutch does engage and spin while engine is running. Yet also spins by hand, with a bit of resistance, with the engine off.

Jibbles8 · August 27, 2019

Know of any good sites for clutches kits or them separately?

davester · August 27, 2019

Check that when the a/c clutch engages is when the a/c makes the racket.

does rockauto.com have a clutch for your van? don't forget to apply the 5% code. I haven't seen a/c clutch rebuild kits, but I also haven't looked for them either. I believe you'll also need a special puller tool to get the clutch off.