Tires that leak...sometimes.

[Batmobile_Engage]

As strange as it may sound, I have had a number of tires over the years that would leak, but only periodically. What the heck is happening?

The most recent instance of this had me almost certain that I must have a small nail that I can't readily see when visually inspecting the tire. I haven't dunked the whole wheel in soapy water yet, and actually I was just going to take the car to Discount Tire (where I bought the tires) and have them take care of it, since it is free and they are right down the street from work. And then....after almost two weeks of this slow leak and a couple refills....it suddenly holds pressure.

This makes me wonder, does this happen only sometimes, because of the position of the tire when I park the car after work? i.e. could a small nail, problem with the bead, or crack in the valvestem only manifest a slow leak if I park with that side of the tire down?

I have had valvestems crack in the past on older vehicles, but this one is much newer, the tires are verrrry new and the valvestems were all replaced with the tires. The last thought I had: Could the valvestem core have been slightly out of alignment, and just so happened to get reseated properly the last time I put the cap back on after filling?

Just trying to wrap my head around how I could have 1 tire drop 1-2 psi per day for two weeks straight and then one day, it's suddenly fine again.

 

[Alin]

Ooh, one of my beloved topics to ponder upon... not! :lol:

Alright well, it can be any number of different variables, which I'm sure you're well aware of. I'll try to keep this post organized and refer back to the order of aspects you've mentioned:

Ever since my incident where the rubber valve stem cracked on one of my STi's rims (in either 2015 or 2016), I've been the most anal person when it comes to tires and air pressure. I have a crate of tools, per se, that I haul in every car now. I check my tire pressures almost daily (alongside coolant and oil). This goes for any car that I'm driving a specific day, or daily. It doesn't matter, I just have to check. Another thing that I have done every time (every time, whether new or used tires!) is to have brand new valve stems put in. I will never deal with another cracked valve stem in my life, that much I can assure myself after going through it once, and also not having a spare set of wheels on hand...

Since it's currently summer and temperature changes aren't too drastic, we can essentially cross that aspect off of the list.

I have a tool (it's actually a cap with the end being formed to mate to cores) for installing and removing the cores, from the above picture. (I hope you do too.) It's definitely one of the variables that could be altering pressure in your tire. Think about a loose core vibrating from all of the road imperfections, including massive craters that OH and MI residents have the privilege of experiencing, and dodging! :lol:

You have to go step by step and cross out possibilities until you come to the conclusion as to what the culprit may be. I assume your post is referring to only one tire, of the four. Which car is occurring with? If it's the Regal, then you have TPMS, correct? Is that how you've noticed that the air pressure has been dropping?

1) Check for visual air leaks, such as using soapy water, on the entire tire! That includes the contact patch, the sidewall, and the mating surfaces to the rim.
2) Check that there are no valve stems that are cracked.
3) Check the cores of the valve stems and ensure that none are loose.
4) Check to ensure that none of your rims are cracked. The slightest crack can allow air to escape. (I know from experience because I'm in possession of a cracked rim.)

If this is just a recent occurrence, and not since you've gotten the tires mounted on the rims, then the following point would be null and void. Another possibility that I've seen is that grime and dirt gets in between the valve stem and the rims where they mate when the valve stem is pulled through the hole of the rim.

 

[Batmobile_Engage]

Thanks for the write up, [MENTION=1172]Alin[/MENTION]. I think I'm leaning towards the valvestem core vibrations theory. Its the only thing I can think of that would be causing this issue to manifest in such a random and inconsistent way. For the life of me, I cannot find my valve core tool, but they're like $1 so I'll get another soon.

I was assuming the worst (nail, screw, f-ed up bead, etc.) since I spend a lot of time on back roads and rutted up turnarounds back in the woods.

Last thing that comes to mind is the caps themselves. I wonder if I get some metal caps, if that might help. I know that the cap has a lot to do with helping keep the core from vibrating free. Maaaybe, if the caps are softened and pliable (just from sitting in the sun, etc.) if they start to lose their effectiveness. Since that should be another cheap thing to try, I might pick those up as well.

 

[Alin]

Thanks for the write up, [MENTION=1172]Alin[/MENTION]. I think I'm leaning towards the valvestem core vibrations theory. Its the only thing I can think of that would be causing this issue to manifest in such a random and inconsistent way. For the life of me, I cannot find my valve core tool, but they're like $1 so I'll get another soon.

I was assuming the worst (nail, screw, f-ed up bead, etc.) since I spend a lot of time on back roads and rutted up turnarounds back in the woods.

Last thing that comes to mind is the caps themselves. I wonder if I get some metal caps, if that might help. I know that the cap has a lot to do with helping keep the core from vibrating free. Maaaybe, if the caps are softened and pliable (just from sitting in the sun, etc.) if they start to lose their effectiveness. Since that should be another cheap thing to try, I might pick those up as well.

All I can say regarding the caps is that you should never use metal ones. Since we live in such horrendous areas for winters and corrosion, the metal caps corrode and essentially fuse to the metal portion of the valve stem. Always use plastic caps! I highly doubt high heat would affect their form. At least, I've never seen nor heard about plastic caps melting. :tup:

 

[Grinder34]

Wow you check pressures daily? If I'm being honest i'm pretty terrible about checking pressures. I only do it on 2 occasions. 1) Before performance driving. 2) When I suspect pressures of being low (visual abnormality, car pulling, car tells me). I guess I should do that more. And definitely floss more.

 

[Batmobile_Engage]

Ahhh the wonders of TPMS. :lol:

 

[Alin]

Wow you check pressures daily? If I'm being honest i'm pretty terrible about checking pressures. I only do it on 2 occasions. 1) Before performance driving. 2) When I suspect pressures of being low (visual abnormality, car pulling, car tells me). I guess I should do that more. And definitely floss more.

Almost daily. :lol: Yes, I check very frequently, though. From my experience, even tires that LOOK good aren't always. I have a legit trucker gauge that I use. I need to see that needle on the number I desire in order to be satisfied. Plus, it takes just a couple of minutes.