Valve sealants are used to prevent leaks around the valve stem, while valve lubricants are used to reduce friction and wear between the valve stem and the valve guide.

Valve sealants should be used when there is a leak around the valve stem. This can be caused by a worn or damaged valve stem seal, or by a buildup of carbon or other deposits on the valve stem.

Valve sealant is typically applied to the valve stem using a small brush or a cotton swab. It is important to apply the sealant evenly to the entire surface of the valve stem.

Valve lubricants reduce friction and wear between the valve stem and the valve guide. This can help to improve engine performance and extend the life of the valve train.