Coolant Temp Sensor for all 6.5TD's 94+. Replace when ses codes indicate sensor failure, vehicle fails to come out of warm-up mode (fast idle),  damaged or as preventative maintenance.  This is the two wire sensor that screws into thermostat crossover manifold. Installs in minutes. This sensor does not work your temp gauge. It is the temp sensor for the ECM (computer)

For the gauge temp sensor that screws into the LH cylinder head, see p/n ssd-053 also in this catagory.