Slow air leak from tire

Have you guys ever heard of tires that develop slow air leaks, then “fix” themselves?

I hadn’t driven my F-Type for over a month (a crime in itself, I know, I know). When I took it out, it complained of low tire pressure in 3 or 4 of the wheels. When I got to the service station, they were indeed a bit low, but not dangerously so.

A few days later I took the car out again, and this time it complained about low pressure in just one wheel. When I got to the service station, the tire was so deflated I could actually see it. It wasn’t completely flat, but visibly low. If I remember correctly, it was below 20 PSI. This is a 295/30 ZR20 rear wheel, so the tire isn’t much more than a rubber band around the rim anyway. If you can see that it’s deflated, it’s bad.

After filling the tire back up to 36 PSI, everything was fine. I’ve been using the car more in the week since then, with no more warnings. Yesterday I stopped by a service station to check the pressures, just to be on the safe side. All 4 wheels were still at 36 PSI, so no leaks.

In all my years of working on cars, I’ve never seen this before. Any thoughts on what could be going on?

Gunnar
'14 F-Type S Convertible

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Yes: it’s a bit inexplicable, and after checking for a nail or screw(using slightly soapy water in a squirt bottle) I then check stems.

I had one that would leak over a period of months.

My wife’s car did this, but I found a screw in it, then plugged it.

Hm, yes, that’s probably it. I don’t have a way to get the car off the ground, so it’s a bit hard to check, but I’ll give it a try. Did you plug it yourself?

Yep… the ONLY ones to use.

Used them on race slicks.

https://www.safetyseal.com/

I had a problem with one tyre that would lose pressure and then not lose it. Turns out there was a spot on the rim where, if the wheel stopped with that spot at the bottom, it would deform the bead and leak slightly.
From memory I had the wheel trued up.

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Every time it’s happened to me it turned out to be some itty biity puncture that would only end up being visible in a tub of water.

That’s why the soapy water spritz: works EVERY time!

OK, I’m going to buy myself a garage jack, a couple of jack stands, and a water spritzer bottle.

Thanks all!

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Don’t forget the Safety Seals!

Realize this is an older post, but in case someone else has had the issue… it could be the valve core. If some dirt or corrosion kept the core from closing, that could be a slow leak. You can easily check if it’s a core problem by taking the cap off and holding a wet finger over it…you will feel the air Cores are usually easy to replace, but best to check what’s involved before going there. I also had Tire Pressure sensor in my Volks Golf that repeatedly would register low air and that turned out to be that the sensor wasn’t tightened sufficiently.

I always check for leaks with a spritz bottle of water and dish soap.

Hi Valerie,

The valve core is indeed a good tip, but in this case it wasn’t necessary to even check it. Wiggles was right, I had a screw stuck in the tire. One time I parked the car the wheel happened to be in a position so that the dang screw was staring me right in the face.

Luckily it sat in the middle of the thread, so perfectly legal and safe to plug. Good thing too, since the tire was fairly new and quite expensive.

Thanks,
Gunnar

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I had a tyre that would sometimes lose pressure, turned out the rim was damaged slightly. It leaked when I stopped and the damage was at 6 o’clock.