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What causes tire valve stem leaks?

I bought new tires a year ago and all 4 valve stems were leaking, I had them all replaced a few weeks ago and another one started leaking again. What causes them to leak?


aluminum alloy rims or stamped steel rims?

If they’re stamped steel, are they really rusty?

BTW, how are you determining the valve stems themselves are leaking?

Do the rims have tpms sensors . . . ?

Alloy rims, they do have tpms. They said they were leaking at the valve stem and I get hissing when filling them, and low tire pressure.


are they aftermarket chromed . . . ?!

Well, even though the massive recall of valve stems manufactured by Dill (in China) took place ~ 8 years ago, it is entirely possible that either Dill or another manufacturer is distributing defective merchandise at this point.

Was it the rubber part of the valve stem that was leaking, or where the center pin of the shrader valve seats inside the valve stem? I’ve had leaks occur at both places, but for me it is usually the rubber part that gets sun-damaged over time and eventually develops a crack. When I fill the tires then the disturbance to the rubber causes the crack to open up and leak there. Putting some soapy water on the valve stem often shows which leak mode it is.

If you have all 4 valve stems leaking from the shrader valve seat, one has to suspect a prank too. It’s easy enough for a prankster to slightly unscrew the valve stem in all four tires. If that’s the problem, just re-tighten the valve stem.

With alloy wheels, road salt gets into the hole drilled to accommodate the valve stem. Rapid corrosion can take place between the stem and the wheel, causing the stem to leak. There are Three solutions…The holes are welded up and re-drilled to the correct size…The hole is drilled to accept a larger valve stem… The wheels are scrapped…SOMETIMES you can clean up the corroded holes as much as possible, dip a new valve stem in rubber cement and install it. Wait a half hour before inflating the tires…It’s worth a try…

Caddyman: didn’t know that. Another good reason to avoid Al alloy wheels. Although my last car had Al alloy wheels and I had no problems over 11 years.