Airplane is 14 Hours only, little dissapointed.
Most probably a hose leak or a joint leak, but the coolant level was below than the level at the preflight.
Minor pirep, the tecnam is a favourite with students but don’t expect it to stand up to the abuse that a Cessna 152 may experience. There is a reason these 40 year airframes continue to appreciate.
You are absolutely right @RobertL18C