A partially blocked cooling passage creates a persistent hot region that follows the tool rather than the heater layout. The affected area may release late, shrink differently, lose dimensional control, or develop a different surface appearance.
Flow and temperature should be measured for each circuit where possible. A low-flow branch, small temperature change despite a hot surface, or abnormal pressure drop suggests blockage, air lock, a pinched hose, or an incorrectly positioned valve. Thermal imaging can localize the consequence but does not identify the hydraulic cause by itself.
Channels should be cleaned with a method compatible with the tool material and deposits. Hoses, quick couplings, manifolds, and filters must be included in the inspection. Drilling or increasing coolant pressure without understanding the circuit can damage the tool or redirect flow away from other zones.