To remove the air cleaner housing for D5244 T to T3 engines, start by disconnecting the mass airflow meter wiring plug, slackening the clamp, and disconnecting the outlet hose from the air cleaner cover. Next, unclip the engine mounting vacuum valve and wiring from the front of the air cleaner housing, then pull the housing upwards sharply to release it from the three mounting grommets while removing the air intake duct. For D5244 T4 to T7 engines, remove the ECM, pull up the plastic cover from the top of the engine, disconnect the mass airflow meter wiring plug, slacken the clamp, and disconnect the outlet hose from the mass airflow meter. Unclip the engine mounting vacuum valve and the wiring loom on the right-hand side of the housing, then push in the centre pin, prise out the plastic expansion rivet, and manoeuvre the air intake ducting from the bonnet cross panel before pulling the housing upwards sharply to release it from the three mounting grommets. Refitting involves reversing the removal process, ensuring that the outlet and intake ducts are clipped securely into position where applicable.