How do you adjust the engine valves on a 4 cylinder diesel Mitsubishi fuso FE-SP?

To adjust the engine valves on a 4-cylinder Mitsubishi Fuso FE-SP diesel engine, first, ensure the engine is cold and remove the valve cover. Use a feeler gauge to check the clearance between the rocker arm and valve stem for both intake and exhaust valves, which should be set according to the manufacturer's specifications. If adjustments are needed, loosen the lock nut on the rocker arm, adjust the screw to achieve the correct clearance, and then re-tighten the lock nut. Finally, recheck the clearance after adjustments before reassembling the valve cover.