Due to the complex nature of the job and the specialized tools and equipment required, servicing the valves, valve seats, and valve guides, commonly referred to as a valve job, should be performed by a professional. An automotive machine shop will remove the valves and springs, recondition or replace the valves and valve seats, recondition the valve guides, check and replace the valve springs, spring retainers, rotators, and keepers as necessary, replace the valve seals with new ones, reassemble the valve components, and ensure the installed spring height is correct. Additionally, the
Cylinder Head gasket surface will be resurfaced if warped, noting that some cylinder heads have a minimum resurfacing height; exceeding this height necessitates replacement. Once the valve job is completed, the head will be in like-new condition. Before installation on the engine, it is important to clean the head again to remove any metal particles and abrasive grit that may remain from the valve service or head resurfacing operations, using compressed air if available to blow out all oil holes, bolt holes, and coolant passages.