Heavy Duty Engine Coolant Thermostat (14948) by Stant®. With 1 seal and without Check Valves. Temperature: 186F. Get fast engine warm-up and dependable engine operating temperature with a Stant thermostat. Stant’s exclusive ELAC® Thermostat Cutaway heat motor has a uniquely formulated thermally expansive wax fill that is precisely calibrated for consistent and precise thermostat valve response.