The 2010 Ford Focus coolant temperature sensor area is in the coolant pipe</br> beneath the air admission line</br> and behind the right chamber head. The coolant should be changed each 60</br>000 miles or something like that. Your air channel should be changed each 15</br>000 to 30</br>000 miles or somewhere in the vicinity. The flash fittings should be supplanted each 100</br>000 miles except if it's a copper one. A cooper flash fitting should be supplanted each 30</br>000 miles. You will come into numerous issues with a motor. A gasket might turn out to be free and that should be straightened out. A flash fitting might fall off</br> causing motor issues. You can have oil breaks and those should be fixed rapidly. A difficult issue is the motor overheating. This might prompt flames and the vehicle detonating. There could be unreasonable oil use</br> requiring the oil to be changed sooner than anticipated.