YAMNAR ENGINE COOLANT LEAK ON A TB016

This problem is on a Takeuchi excavator tb016 2003 with a Yamnar TNE 3-68.engine. Maybe some one can help me... After sitting for 4 month, I notice that there is a small leak of coolant, droplets, on the bolts that hold the engine oil pan on the fuel pump side.It is very difficult to see around the coolant pump, but the drain of the pump is dry so it is not by the seal of the pump. Every other place seems dry. Any one could give me some advice ? thank you for yours comments. Ronald.

YAMNAR ENGINE COOLANT LEAK ON A TB016