Went to enterprise and rented a car that had literally 4 leaking tires and they filled them all up to 55 psi before handing the car over. This photo was taken after the 30 minute drive home.
Called and took the car back in for service only to get the same car, same 55 psi on all wheels, and same major leak in the rears. Went to another enterprise location to get a normal car instead 2 days later. Really took me back to my first car, but it’s a lot less fun when it’s not even yours and the “fix” is just dangerous overpressure.
Leaking valve stem, or less likely a cracked rim. A 5$ fix while the tires were off; but more work just to fix on it’s own. If it’s a slow leak you keep ontop of, you may as well wait till the next tire rotation; make sure you request they replace the valve stem(s).
In warm weather, it might last all summer. In the winter, I can go maybe 3 months before the low pressure warning comes on. I’ll get new valve stems next time I get tires. For some reason, that hadn’t really occurred to me.
Some of these newer alloy wheels are harder to mount. If you let them know there’s a history of leaks on that tire they may apply tar to the rim which can go a long way. My car has had a lot of issues on one tire until I found the right mechanics, ironically they were also the cheapest (small business who specialize in used tires). Later after getting new tires the problem went away without the tar, so I think it comes down to surface prep.
You could try tightening the valve core too. But 3 months isn’t really a slow leak. You should probably fill your tires that often anyways
Could also just be the rim being kind of dirty and corroded and needs to be cleaned up a bit of bead sealant.
I’ve had it happen to me a couple times, tires just always lost air sort slowly, I never cared enough to bring it in just for that, not a big deal to stop by the air pump once a week or so when I was getting gas anyway.
I’m sure if you brought your car in just for that they’d probably slap some token $10-50 price on it.
But if you bring it in for another service I feel like a lot of places will just do it. I know I brought my car in to pep boys one time for an oil change or something and asked them to look at it and they just did it, no extra charge.
I feel like it’s one of those little things that no one is quite sure how to write it up in the system, and figuring it out is more of a pain in the ass than just not mentioning it to the boss, not like he’s gonna notice they used an extra scrap of sandpaper and blob of sealant anyway.