The Stovebolt Site Forums The Shop Area General Truck Talk Radiator Cap Trick?

I think Joe means the hole in the flange of the thermostat, although putting a hole in the housing would let the air out - as well as the water
a hole in the rad cap would keep down the pressure but easier to leave the cap loose, just on the first 'click', which would help slow down any weeping from rad seams and pinholes

Bill