– Clean valve guides using a valve guide brush.
 – Measure valve guide inside diameter using a ball or telescoping snap gauge.
If valve guide inside diameter exceeds wear limit, replace guide.
If valve guide inside diameter is less than wear limit, determine guide-to-stem clearance (Valve guide diameter minus valve stem diameter). If clearance exceeds wear limit specification, replace valve guides.
If necessary, replace valve guides using JDE504 Valve Guide Driver. Install valve guides with tapered ends down. Push valve guides down until top of valve guides are projecting the specified height (A) from the valve spring seat in the cylinder head.