[Vwdiesel] Manual AC cycling

[Tad]

Guys - I've got a little technical question about A/C that I've wondered
about for a while, and I know you probably have opinions, so here goes.
So on standard electrically-powered air conditioners, they have a warning
about not turning it off and right back on again or damage will result...
wait 3 minutes before turning back on, etc.  Some have an automatic lockout
to prevent you from doing this.

Now I've never heard a technical explanation as to *why* this is, but I
assume it's something like this: when you turn off the unit, it's still got
a full head of pressure in the system.  If you were to turn it back on
immediately, the electric motor driving the compressor would have too much
load and risk overheating or overloading or whatever.  Waiting 3 minutes
allows the system pressure to drop.

I've never heard of such a warning for automotive (belt-driven) AC, but I
wonder if the same theories apply.  Clearly the car's engine doesn't have
the same load restrictions that an electric induction motor would, and you
probably don't have to worry about snapping the belt, but what about the
pump, or seals?  Since they're operating under those same pressures in
nominal operation, I'm not sure that it would make any difference.

Why do I ask?  Because I enjoy the benefits of AC, but I don't like the MPG
penalty.  I sometimes try manually cycling it so it only runs during
MPG-optimal times, such as when decellerating, braking or coasting downhill,
but I wonder about the wear-and-tear penalty on the system.

Comments?

Thanks for any input.

Tad