[MGRMLN]

As is previously mentioned, the coolant tank on i8's are located below the highest point of the ICE engine. This means the entire system needs to be pressurized in order for the coolant to reach the uppermost part of the motor. If you open the coolant reservoir, you will introduce bubbles in the coolant causing areas of the motor to overheat, leading to catastrophic results. Go to the dealer or a qualified shop that has pressurized coolant gear, like shops that work on water cooled Porsches. They have a similar system I'm told.

If you open the front, and the reservoir bottle is at half or above, you have a bad sensor. It is built into the tank itself so the entire thing will need to be replaced. My 2015 had this issue.