Trucks been running fine, had it two years. This morning I noticed heater not getting hot (about 20 degrees outside). Within about 5 miles truck went from midline on temp gauge to overheated and losing coolant. Pulled over and cooled down fairly quick. Drove the last mile to work. Changed thermostat and refilled coolant after pressure checking radiator and holding at 15 pounds. Started up and over heated again. Threw out P2181 code (coolant system problem). Coolant wasn’t full again but didn’t drip out from motor. No coolant in my oil, no white smoke from tail pipe. Top coolant hose going to radiator was very hot and I couldn’t feel coolant going through it. Small drip from tail pipe I didn’t notice before but I don’t usually look down that way as I usually back in when parking. Got a combustion gas tool and it showed gasses in my coolant. Just looking for guidance on whether to shoot right to head gasket or if there’s some other reason I may not be seeing.

 

If the test came back positive, that is highly likely to be a blown head gasket......