Tire Valve Leaks Air when caps are off

[Hamtaro7]

Hey all I noticed that when i remove the caps from my tires the air is coming out quite notably. When the caps are on its fine. Just Wondering is this something that I should have the caps replaced or is it safe to just use as long as the air pressure is not leaking. TY

I have aftermarket tsportline wheel and tires.

 

[rolling green]

If you take a cap off can you see the valve core? I recall getting a set of TPMS once and 1 did not have a valve core installed. Air should not leak when you remove the caps

 

[MY-Y]

Valve core is loose, broken, or has dirt in it.

Step 1. Push the pin in to expel some air and see if the leak goes away.
Step 2. Get a valve stem tool (auto or bike store and tighten core.
Step 3. Replace core.

 

[Tronguy]

FWIW, an old-timey check on the valve core is to take off the cap, take some spit, and cover the end of the valve. If it's bubbling, tighten the core.

Back when I rode bicycles all the time (work delivering newspapers as a teen, commuting between dorms and school) and said cores were seeing a lot of use, they'd go bad from time to time. The tool mentioned by @MY-Y can be used to unscrew the core, remove it, and put a new one in. But if one does that, better have something under the car so the tire's sidewall doesn't get squished while the air is whistling out.

Of course, bicycle valve cores typically run between 45 to 90 psi, at least with Schraeder stems, so they're under more strain than ye typical auto tire, even with Teslas.

 

[jcanoe]

It would be highly unusual for multiple valve cores to become loose at the same time unless someone tampered with your vehicle. You can purchase a valve core tool at any auto parts center. The valve core tool is sometimes included in a package with replacement valve cores. Be careful when removing the valve core (try tightening the valve core first, see if that corrects the air leak). When removing or replacing a valve core always have a source of compressed air to reinflate the tire right there where your vehicle is parked. Attempting to roll or drive on the flattened tire can break the bead seal, then you will be unable to reinflate the tire without first reseating the tire bead.

 

[fiehlsport]

If the technician who mounted the tires didn't tighten the valve cores adequately, this can happen. My friend had this occur on two wheels that he got from Tire Rack!

Easy fix, though. But human error does cause this sometimes.

 

[MrFixit1094]

I will second the theory of a loose valve core. My neighbor recently purchased a Model 3 and had a slow leak in one of his tires. After spending a fair amount of time troubleshooting, he found that the core was loose and all he had to do was tighten it with a valve core tool

 

[ngng]

It would be highly unusual for multiple valve cores to become loose at the same time unless someone tampered with your vehicle. You can purchase a valve core tool at any auto parts center. The valve core tool is sometimes included in a package with replacement valve cores. Be careful when removing the valve core (try tightening the valve core first, see if that corrects the air leak). When removing or replacing a valve core always have a source of compressed air to reinflate the tire right there where your vehicle is parked. Attempting to roll or drive on the flattened tire can break the bead seal, then you will be unable to reinflate the tire without first reseating the tire bead.

If you drive on a tire without air it will destroy the sidewall and you’ll be buying new tires

 

[Hamtaro7]

The tool to tighten the valve core is easy to use? i will try to order one

 

[MY-Y]

The tool to tighten the valve core is easy to use? i will try to order one

Yes. It just slips inside the valve stem and the slot engages the core. You just snug it down - not too much torque.

Please report back to the group on your results.

 

[fiehlsport]

The tool to tighten the valve core is easy to use? i will try to order one

They are super common at any auto parts store for a few bucks if you want to do it in the parking lot and get it done with quickly.

Remember, it just needs to be snug - minimal torque on these. Might be worth cracking loose a known-good core, then re-tightening it just to see what it should feel like.

 

[jcanoe]

The tool to tighten the valve core is easy to use? i will try to order one

Very easy to use:

Tire valve stem core tool, replacement valve cores

 

[Tronguy]

The tool to tighten the valve core is easy to use? i will try to order one

They're a couple of bucks. Any auto parts store, no matter how benighted, and probably at Walmart.

If there's a bicycle in the house, you can practice on that. Same tool.

If you look at a tire stem (i.e., the thing that you put a pump onto in order to inflate a tire), you'll notice that the stem has one set of threads on the outside (into which the cap is screwed onto) and another set of threads on the inside, into which the valve stem is threaded.

The valve stem has a couple of rubber gaskets that keep the air from leaking out. One of them is compressed and seals the body of the valve stem when the valve stem is screwed down a bit and tightened. Don't overdo it or you'll break the rubber O-ring. Snug, not over tight.

 

[Iron]

If the technician who mounted the tires didn't tighten the valve cores adequately, this can happen.

^^^This ^^^

Here is how you use the tool. Do it quickly and be near an air hose cause you'll be losing air fast.

 

[Hamtaro7]

big thankyou all, bought the tool and tightened every core, not sure why all 4 were so loose

saved me a trip to tire place and potentially getting scammed

 

[ngng]

big thankyou all, bought the tool and tightened every core, not sure why all 4 were so loose

saved me a trip to tire place and potentially getting scammed

If you are taking your car to a shop that you automatically assume is going to scam you should find another shop.

 

[Noflash]

Just got back from a week's vacation and my wife's mylr had one tire down to 22 psi. I noticed the cap was missing. While I added air I noticed the other three caps were not completely tight. I don't recall ever losing a cap on 30+ years of car ownership. Nor did I think one missing could lead to a leak. I replaced it with a bike tire cap I had in the garage. Just ordered some new plastic ones off Amazon. I suppose I will replace all the caps on my three cars. Does that count as a new year's resolution? If we lose any more air in the next week, I'll send her back to Discount Tire that installed her TSportline rims and CC2 tires a month or so ago.

 

[Iron]

Did you not read this thread? The caps are just for keeping dirt out. Likely DT didn't tighten the valve stems cores properly. Get the tool and do it or take it back.

 

[jcanoe]

Just got back from a week's vacation and my wife's mylr had one tire down to 22 psi. I noticed the cap was missing. While I added air I noticed the other three caps were not completely tight. I don't recall ever losing a cap on 30+ years of car ownership. Nor did I think one missing could lead to a leak. I replaced it with a bike tire cap I had in the garage. Just ordered some new plastic ones off Amazon. I suppose I will replace all the caps on my three cars. Does that count as a new year's resolution? If we lose any more air in the next week, I'll send her back to Discount Tire that installed her TSportline rims and CC2 tires a month or so ago.

The caps on the tire valve stem are there to keep out dirt and water, not to maintain the tire air pressure. You need to use a valve core wrench and slightly tighten the valve core in each valve stem. An automotive parts store would have the valve core wrench (the valve core tool is often included with a package of a half dozen valve cores.) Also sold on Amazon.

LPT: Don't install aluminum valve stem caps. The aluminum will corrode when exposed to road salt making it impossible to remove the cap when it is time to add air. Stainless steel valve stem caps don't corrode when exposed to road salt or just purchase the basic plastic valve stem caps.

 

[jcanoe]

The caps on the tire valve stem are there to keep out dirt and water, not to maintain the tire air pressure. You need to use a valve core wrench and slightly tighten the valve core in each valve stem. An automotive parts store would have the valve core wrench (the valve core tool is often included with a package of a half dozen valve cores.) Also sold on Amazon.

LPT: Don't install aluminum valve stem caps. The aluminum will corrode when exposed to road salt making it impossible to remove the cap when it is time to add air. Stainless steel valve stem caps don't corrode when exposed to road salt or just purchase the basic plastic valve stem caps.

If tightening the valve cord does not stop the air leak at that tire then you will need to remove the valve core and clean out any debris from the valve core (else replace the valve core with a new core; they are inexpensive) before reinstalling the valve core. Do this only when you are parked close to a source of compressed air because the air will quickly escape from the tire as you loosen the valve core. Don't move the vehicle when the tire is deflated as you can damage the sidewall and also can break the tire bead seal. If you break the bead seal you won't be able to re-inflate the tire until the bead is properly re-seated.