Question: I noticed my tires looked low on air, so I decided to fill them up while I was at the gas station. I got to my third tire when the valve cap rolled away on me, and I never ended up finding it! Can you tell me if my tire will go flat if the valve cap is missing?
Answer:
Your tire won’t go flat immediately after losing the valve cap, but you should replace the cap as soon as you can.
Is it bad if a tire valve cap is missing?
The primary function of the valve cap is to keep out dirt and moisture out of the tire’s valve stem. Without the cap, there is a risk that dirt or road debris can get inside the valve mechanism, potentially causing air to leak or the valve to malfunction.
The valve stem, usually equipped with a Schrader valve commonly used in automotive and bicycle tires, relies on a spring-loaded core that allows air to be added and keeps it from escaping. This is why you hear hissing when you press on the center of the valve with your finger.
When you drive on the road, your valve might collect debris, snow, water and other contaminants that can interfere with the sealing capability of the valve, potentially leading to air leaks or valve failure. Moisture that enters can also freeze in colder conditions, blocking the valve or forcing it open, both of which can lead to tire pressure issues.
What happens if you lose the cap to your tire valve?
If neglected over a long period, losing the cap to your tire can lead to damage to the valve, causing an air leak.
If you don’t regularly check your tire pressures, underinflation can accelerate tire wear, decrease fuel efficiency and increase heat that can cause a blowout.
Replacing a missing tire valve cap
Valve caps can be found at auto parts shops or even on Amazon. They are generally black, but if you had nitrogen pumped into your tires, you might have received a red or green cap. Replacing them is inexpensive, easy and can extend the life of your tires.
Xuyun Zeng is a content strategist with a wide-ranging content background including tech, journalism, cars and health care. After graduating with highest honors in journalism, Xuyun led a newspaper to win eight awards, helped start an award-winning film industry podcast and has written over a hundred articles about cars repair, state laws and insurance. Prior to joining Jerry, Xuyun worked as a freelance SEO consultant with a mission to create the best content that will help readers and grow organic traffic.
Phil Metzger is a personal finance editor and writer with more than 30 years of experience editing and writing content across a variety of industries. In writing and editing for Jerry, Phil’s mission is to help car owners better understand their vehicles and the costs associated with car ownership. Before joining Jerry, Phil worked as a writer and editor for newspapers, magazines, television radio and online news. His work has appeared in many major publications and websites over the years, including a series he edited that was a finalist for a Pulitzer Prize.
