Hi, My son changed the engine coolant thermostat sensor in his 98 corolla. Now engine is overheating. All the fluids are topped off in radiator and overflow. No leaks. I thought it might be an air pocket in the block. He changed the ECT sensor on a slight downward grade w/ engine at lowest point.. I reversed the position of the vehicle and ran vehicle w/radiator cap off. The engine is hot to the touch, but it doesn't seem likes it over heating. Dash warning light is off now. Leaning towards thermostat at this point. open to suggestions.