QSC8.3 and QSL9 Engine Identification Section E - Engine and System Identification Page E-3 NOTE: Depending on the manufacturing plant, calibration data may also be be found on the engine dataplate. If the engine dataplate (1) is not legible, the engine serial number (ESN) (2) can be found on the engine block, on top of the lubricating oil cooler housing. Additional engine information is on the ECM dataplate.