07 explorer excessive coolant use

[RonWG]

Hi everyone!
I've had to refill my engine coolant 3 times within 50k miles. Each instance
the coolant level was very low, the coolant reservoir was empty! I can see no leaks around the engine and no smell of coolant. I owned a '96 Explorer and drove it for 280k miles not once having to add coolant. Where is the coolant
disappearing to????

Thank You,
Ron:exp:

 

[anton831]

i have a 98 do you have the plastic thermostate casing that holds the thermostat its like a kidney shaped black plstic