Posted January 12, 2016. Hi all.well im basically stumped..the problem is that my back seats are soaking wet and the part you lay back on. but the headrests are dry all of the roof liner is dry all the foot wells and carpets are dry.the only places that are wet are the bit you sit on and lie back on all the rest is bone dry. Duralast Coolant Temperature Sensor SU2301. Part # SU2301. SKU # 364419. Limited-Lifetime Warranty. Check if this fits your Ford Fiesta. $2799. Select store. for pickup availability. Standard Delivery by Jan. 03. I have a 1.6Tdci which I suspect is running colder than it should do. The temperature takes a while to reach near to 90° (88° perhaps assuming each division is 15°). The temp will then drop down to nearer 75° (2nd division) and then hover between 75 and 80ish). The temperature never reaches 90° again. The question is therefore how much the JasonH. I agree a modern car shouldn't have a fluctuating temperature gauge. If it does then the thermostat or temperature sensor are faulty. A faulty thermostat will cause the car to take longer to warm up and therefore increase fuel consumption. Running at low temps can clog up the DPF and soot up the EGR etc. Ford Model: Focus 1.6 tdci titanium Ford Year: 2010 Ford Model: Focus 1.6 tdci Ford Year: 2007 UK/Ireland Location: Other/NonUK Share; Posted September 16, 2014. Most cars have a coolant temp sensor that controls the gauge, maybe some other stuff. Then there is a head temperature sensor (maybe goes by another name). This is used by the engine control system. The coolant temperature sensor is usually located on the radiator, maybe on a radiator hose, maybe on the thermostat housing. Gntk.