Default engine RPM goes up when A/C is on but not when idle

[autoque]

You know how turning the A/C compressor on raises the RPM needle a couple hundred up. But with mine it's a little weird. When the vehicle isn't moving and at idle, turning the A/C on does not do anything to the RPM. Only when I push on the throttle, drive forward and settle down to idle, then can I see the base RPM is increased as it should. So theoretically, if I turn the A/C on at idle and just stay there for an hour, the compressor would be running without loading the engine for all that time. Or I have to manually throttle it and increase the RPM once to raise the base RPM with the A/C on.

Is this supposed to be normal? Does anybody else experience this?

[ard]

Hard to know if the AC compressor is really turning on just because you select the AC internally- the car may actually only engage the compressor when you start moving off idle?

But the AC causing a 100-200 rpm increase in idle speed is common- as is a higher tendency to creep as the AT engagement is controlled by engine speed.

A

[autoque]

Originally Posted by ard

Hard to know if the AC compressor is really turning on just because you select the AC internally- the car may actually only engage the compressor when you start moving off idle?

I still get the cool blow from the vents even though the RPM doesn't change so I thought it's the compressor working.