Sorry you did put in your first post about sender. My mistake. Maybe the fan is not kicking in when it should. But why it would suddenly start to work when you take it out of gear and rev? At first I thought air in system. Thermo sticking but you replaced it. Try bleeding cooling system. And replacing coolant temp sensor. The sensor is the same as the switch on your car they both start radiator fans going. Try starting the car with hood up and wait till the radiator fan starts. If it doesn't and the temp continues to climb. Waggle the wires on temp sensor and wires on fan motor to see if the fans come on? Of course the actual sensor maybe faulty not the wiring? Even the fan motor could be the fault. But again why suddenly start when changing gear?
Coolant Temperature Sensor (CTS)
The CTS monitors engine coolant temperature. This sensor is mounted in thermostat housing. Coolant temperature information is used by SBEC to slightly enrich or make lean air/fuel mixture, adjust idle speed and control cooling fans as necessary, according to engine temperature. On turbo engines, CTS is also used to control boost levels and spark advance.
Monday, December 8th, 2008 AT 8:01 PM