My old Zetec ran between the M and A when I first got it, then after changing the water pump (preventive while doing the timing belt), did the same until it overheated one day and the timing belt cover was spewing with coolant out of every crack. I guess the new WP had a leak... only overheated once after that (summer with the A/C on delivering pizza), but it would run just under the red to just on the red (which is when the fans would kick in). I figure the WP had a small leak and wasn't able to pressurize the system, which caused it to run real hot.
So yeah, I was always on the edge of overheating the 1.5 years I had it after the WP change.
