I'm trying to figure out if the thermostat is leaking. Above the thermostat on the engine block it appears something has been getting it wet. It almost seems like it's coming from that drain bolt to the left of the bleeder screw that screws into the engine. The coolant level has dropped slightly in the last couple of months. Btw it's a 2012 justa. Any thoughts?

 

I have seen them leak on the top near the neck, but its rare. Is the bleeder screw dripping coolant at all or is the neck leaking. You will have to have the car up to operating temp to check it. Most leak on the bottom side of the seam. But I have seen the neck. Check that screw. Pop is out when cold and fill up the expansion tank. You have a 2011 Cooper N16 engine with the pre conversion, its you go to a new thermostat , you will need that new wire lead adapter as the sensor is now at thermostat. They cahnged the design set up like the 3/2012+ Cooper's .

 

I'm in the middle of changing thermostat and it seems I will need to disconnect the three connectors in front of motor in order to move wiring out of the way. Does anyone know how to unplug the blue one shown in the pic.