Is Missing Tire Air Cap OK? What Should I Do To Solve?

What to do when missing tire air cap?

We all know the importance of wheels and tires. They are the main parts that contact the ground and balance the vehicle.

That’s why we should always ensure they’re in the best condition and properly inflated to avoid unexpected accidents.

One day, you are checking the tire and detecting that the air lid is lost; what should you do? What will happen when you’re driving?

All the detailed information will be revealed in the next sections! Keep reading to know more!

What Is An Air Tire Valve Cap?

missing tire air cap

Before learning more about tire air cap missing, you should know more about this part and its purposes. In short, the valve cap is important in stopping leakage and tightening the valve.

On the market, you can find products with three main types:

  • Plastic dome: When moving the car on the road, this type is the most popular due to a good air retention effect inside.
  • Metal dome: This material stands out for its ability to withstand temperature changes, especially on race tracks. An O-ring or rubber washer is popular to seal it better.
  • Metal “screwdriver”: It includes knurled edges to facilitate tightening or loosening them, and some metal ones have hex head patterns.

The Purpose Of Air Valve Stem Caps

Each detail on the vehicle has its mission, and this part is the same. What functions does a cap perform? 

This part is designed with a little rubber seal on the inside to stop any infiltration of debris or other objects into your tire valve.

It is intended to safeguard your Schrader valve and stems into which a stem core is threaded.

The Schrader valve needs a stem cover; otherwise, dirt and moisture can get inside the stem and possibly clog or contaminate the sealing surfaces, leading to a leak.

The rubber washer or seal also acts as a cushion between the lid and the stem to stop it from losing and falling off due to vibrations.

A stem lid is essential for keeping moisture and debris out if your car has a tire pressure monitoring system (TPMS).

Is Missing Tire Air Cap OK?

No, missing tire cap leads to no serious problems, for short. But keep in mind that it is only acceptable for a short time, and you need to install a new one as soon as possible to avoid further damage in the future.

The caps, as mentioned above. In the case of a tire cap missing, its leaks can seriously harm all of your tires’ components and reduce their fuel economy.

Your car uses more gas as a result of the pressure drop. The wear-out pace also rises when air escapes.

Low pressure can cause the inside structure to get hotter, especially while traveling at high highway speeds. So a lost cap to tire air might cause a blowout. 

A wheel blowout is a worst-case situation, so you may still need to pay for expensive repairs depending on how worn or damaged it becomes. 

Do Tires Lose Air If The Air Tire Valve Cap Is Missing?

tire air cap missing

If you lose the cap to the valve, will it lose the air inside? The answer is absolutely no!

In general, a tire missing air cap is a common issue. But try not to stress too much. Because the truth is that without a lid, your wheel won’t lose air.

Although it has a significant role, the valve cap does not impact how it circulates inside it. This cap’s primary function is to shield its stem from debris and moisture.

Only when you press the stem can you release air.

That said, the air can come out over time if the cap falls out or hasn’t been properly tightened. Therefore, it’s critical to keep the lid in place.

Additionally, a collision may cause it to pop off. The scraping effect from brushing up against the curb could also remove the stem one. Additionally, it may take a toll on the stem, which could result in leakage.

The most frequent cause of no valve caps is that they are misplaced. It is easy to lose the lids when you remove them to inflate. They should be stored safely for reinstallation after inflating the tires.

What To Do When Missing Air Valve Cap? 

If I lost tire cap, what should I do next? You should find the replacement as soon as possible, as you can avoid more serious issues related to the wheel bearing, valve system, etc.

The valve stem lids fit most models. Walking into any auto repair shop, you may have stem caps replaced that are perfectly compatible with your tires.

It, however, can be different if you drive heavy-duty trucks or specialized farm machinery. Yours might need to be purchased from an accessories shop.

Why Do You Lose Air Tire Overtime?

That you lost tire pressure cap isn’t the reason that leads to losing air inside it.

If you find these parts are deflated frequently, even when regularly inflating and weighing your tires, a few culprits may be worth considering.

Improperly Function Of The Valve Stem

Due to prolonged chemical contact, valve stems may degrade and cause air loss. They are the channels that enable us to inflate or deflate it as appropriate.

The valve stems should typically be changed anytime you purchase new ones (about every 6-10 years).

However, because of the rough roads and bumps, it may sustain damage earlier. This leakage may also occur if you tend to over-tighten its stem cores after filling your tires.

Keep the torque at roughly 4 inches per pound to prevent this. You may keep this up by using a pre-set wrench.

In short, you might need to replace the stems or their cores if you find that your automobile gradually loses air at a pace of more than three psi per month.

Fluctuate Temperature

The air inside tires contracts as the temperature drops. It also expands as the temperature rises.

Every 10°F drop in temperature causes around 2% of the air in the car wheel to be lost over time. The inflation rate likewise increases by 2% for each 10°F rise in temperature.

So in the US where the temp difference between day àn night might hit 20°F, they lose around 4% of their original air amount.

Accordingly, depending on the suggested inflation rate, you can notice a fall of 1-4 psi if your car was left outside during a cold night. You can use a tire pressure gauge to check for precision.

Nails In Tires

nail in tire

A nail in it might bring a 2-3 PSI drop per day. Its performance could be significantly worsened or even become dangerous to drive on after just two days with such a leakage.

Although there won’t be much pressure loss if the nail remains in the tread, you shouldn’t leave it there.

More pressure is applied to the nail as the tire rotates, severely damaging the tire and increasing the risk of a blowout.

There is a chance when your car sounds like it has a flat tire, but it doesn’t. So, don’t forget to inspect the tires carefully.

The Wheels Are Pulled Away From Your Tires

The wheels on your vehicle are designed to fit the tires. So, an air leak may result from a bent or broken wheel, gradually ending up with a flat one.

Curved wheels will also increase vibration in the car, which does no good.


Can You Drive The Car Safely Without The Tire Valve Caps?

Can I be safe when driving with the missing cap on tire

You can continue driving! The valve cap’s main function is to retain air inside in case it ever leaks while also keeping dirt and debris out (spraying some Windex on the valve to check it).

Even though you can still drive even if the valve cover is missing, we advise a replacement as soon as possible to prevent debris and dust from getting into your tires.

Fortunately, air valve caps are fairly simple and inexpensive to repair, and they are available at large auto parts shops and internet vendors.

Both plastic and metal caps are available; however, we suggest using the former. Removing metal caps will be more challenging when re-inflating your parts since they can corrode and fuse to the stem over time.

Are Tire Valve Caps Universal?


Most of the time, you can easily find the right valve cap model. As mentioned above, auto parts stores have a lot of models, and even online shopping is acceptable.

So if you own vehicles of popular brands such as Toyota, BMW, Fort, etc., this is completely easy.

However, finding it will be a bit more difficult if you own premium wheels or special vehicles. It would help if you went to their affiliated retail store or service center to replace it.

How Much Does It Cost To Replace Missing Tire Valve Cap?

If you’re about to replace the cap for tire pressure missing, you should know how much it costs.

A large box of valve lids costs $10 or less at the neighborhood automotive parts store. You can pay more than the average price if you need anything for heavy-duty trucks or if you want something special.

Additionally, installing a valve stem lid requires a few minutes without assistance.

Changing the valve stem in a wheel is also a reasonably simple procedure. It can cost you around $10 if you can do it yourself. Otherwise, anticipate paying $25 – $50 at your neighborhood shop.


Can you continue driving when missing tire air cap? Of course! Just keep calm as the performance will still be ensured and stabilized.

However, you should find out about the replacement as soon as possible. Otherwise, you may have to face more serious issues and pay more to fix them.

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