92 2.5 300D Runs Hot With A/C On

During the winter, spring and early summer this year, before I had reason to use my A/C regularly, I noticed that my temperature guage seemed pretty much glued to about 82 degrees celsius.

Since I've been using my A/C regularly, I notice that the temperature can spike up as high as 101 degrees celsius. When I turn off the A/C under such circumstances, it comes back down to normal pretty rapidly. Could this be a problem with the A/C cooling fan?

I don't think it's a cooling system problem since my radiator, thermostat and temperature sender have been replaced within the past 4 months, and the temp guage and temp guage wiring were both tested to make sure they were OK.

TIA,

--Duncan