Tire Valve Stem Caps – Do Your Tires Need Them

Tire Valve Stem Caps - Do Your Tires Need Them?

Have you ever gone to check your vehicle's tire air pressure and found the cap that screws on the valve stem was missing on one or more tires? You may have thought you were lucky because you had easy access to the valve stem, thereby making it easier to add air to your tires. Maybe you were worried and went to your local auto parts store to buy a replacement cap. Or maybe you just didn't think about it at all.
Everything on your vehicle that was equipped by the manufacturer serves a purpose, big or small. Something as small as a tire valve stem cap may seem insignificant, but it actually serves a pretty big purpose. The valve stem cap is not just a little plastic or metal cap to make the valve stem look nice. It is designed to protect the valve, a valve stem into which a valve stem core is threaded, that keeps the air or nitrogen in your tires.
A valve stem cap is important for the valve because if one is not fitted, dirt and moisture can enter the inside of the valve stem, potentially jamming or contaminating the sealing surfaces and causing a leak.
Metal, and some higher quality hard-plastic valve stem caps, often have a rubber washer or seal inside to help make an airtight seal. This type of cap protects from dirt and moisture and also helps prevent air from escaping from a slightly leaking valve. In addition, the rubber washer or seal prevents the cap from loosening and falling off due to vibrations by acting as a cushion between the cap and the valve stem. Most caps, however, are a softer plastic designed for protection only and are not equipped with a separate seal.

If you take your vehicle in for a routine service that includes checking the tire air pressure, the valve stem caps should be properly tightened, and should be replaced if missing. If you find a mechanic who does this, you have found a keeper! Any mechanic that flags this issue as part of a used vehicle inspection is one who understands how important it is to be thorough even when it comes to seemingly insignificant things.