Jeep Wrangler problem: Thermostat?

yeah, a bit of both. when I wrenched back in the day, grease/oil/dirt would get in the tiny cracks and crevices of the skin of your fingers. and it didn’t matter how many times you washed your hands, they still looked dirty.

Yep, the bleed valve on the thermostat housing is easy to open/close with a screwdriver. This coolant funnel kit is really cool. I didn’t spill a drop!