> I found that my replacement fan, a muffing fan, came one and stayed on
> much more than the stock fan. I thought the shroud would help and
> provide better convection flow over fins.
>
> Well it seems to have had little effect on the duty cycle of the
> muffing fan.

Alistair:

I posted last fall my experience with fans.  Briefly,
I replaced the original rear cooling fan with TWO
Radio Shack muffin fans.

The fans came on early and ran all day--into the
evening.  The fridge struggled to keep cold (<--my
interpretation.)

I removed them and put in a single Volterra fan that
is the current (best) stock replacement for the rear fan.
Back to "normal"--fan comes on when hot, runs, cycles
off, back on, etc, etc.  Fridge runs fine.

My conclusion is that the muffin fans (computer fans)
are a mistake.  (Understatement....  ;-)

                        Richard A Jones
                        Boulder, Colorado