Stop in for a cup of coffee

Only thing I can think of is this happened when it was -17 degrees, 3 miles from home and the engine wasn’t up to full temp. We had just left a wrestling tournament in town after the truck had sat for roughly 9 hours in that cold without being plugged to a block heater. It took several intake heater cycles to even start. But there’s also no mustard on the thermostat on ether side, nor any oil residue. So I’m totally stumped. Really worrying that it’s not effect a head gasket but a cracked block or head…