With Expertise Built In , the OTR Cylinder Head Assembly for Caterpillar C15 ACERT is essential to the airflow in and out of the cylinders as well as fuel deployment. This heavy duty engine cylinder head assembly boasts 30% more coolant flow, aiding in keeping the truck's engine cool in harsh environments. Replacing your heavy duty cylinder head assembly with new parts, including an all new valve train, cam bearings, injector tubes, and valve guides, this OTR cylinder head ensures a smooth ride with maximized performance on the road ahead. FleetPride is your First Click in Heavy Duty .