When I was a young lad, one of my early motorhead mentor/teachers who was a die-hard Mopar guy taught me to always drill a small hole in the face of thermostats when putting in a new one.
The theory was to allow any trapped air to escape while it was filling.
I've always done it and never questioned the logic.
Anyone else?
Decades ago most thrmostats came with a hole in the flange along with a "jiggle pin " in the hole that would break the surface tension of the air bubble trying to pass through the hole, very effective.
