1537023 Fits Caterpillar Fits CAT Industrial Construction Engine Intake Valve 34One New Aftermarket Replacement Engine Intake Valve Fits Caterpillar (Fits CAT) 3406E, C15, C16, C18 Engines This aftermarket replacement inlet valve fits the cylinder head of Fits Caterpillar (Fits CAT) 3406E, C15, C16, and C18 diesel engines. The intake valve seats in the cylinder head and controls airflow into the combustion chamber, making it a critical component for proper engine compression and performance during overhaul or top end rebuilds.