Just replaced my coolant cap which was leaking very slightly. Was the original cap from '97 with the .00 part number. New part is .04.
Thought I noticed higher operating temps recently, which is what hand me sniffing around the cap. Nothing absolutely dramatic - normal temps on the cruise, but was quicker to build heat and spin the fans up in stop start traffic.
Haven't had a chance to fully test the new cap, but was wondering whether a leaky cap and presumably some pressure loss would push up operating temps a bit?