I got new tires around Thanksgiving. Let’s call it Nov. 25.
About three weeks later, just before I was going to drive home for Christmas, I got the low tire pressure warning on my dashboard. I checked all four tires; three were fine in the 32-35 psi range, the rear passenger-side tire was down to about 20. I (hoped) it was just a fluke of the cold weather, filled it up, and drove home.
Three weeks after that, I got the warning again. Checked it again, same tire, down to about 22 psi. This time I filled it up but went back to the (Ford) dealer where I bought them. Told them the tire wasn’t holding pressure, etc. They checked it out, claimed they put it in the “dip tank” (I assume a water bath to look for escaping air bubbles) and couldn’t find anything. They didn’t charge me anything for this, and said, “well, it’s holding pressure. So come back if it repeats.”
Today (again, about three weeks later) I got the dash warning “low tire pressure” again. Same tire.
So questions:
Is there something that would cause such a slow leak? Something they should be looking for? They looked before, and didn’t see anything obvious like a picked-up nail or anything.
Should I go to a dedicated tire place? Like I said, I took it back to the dealer that sold me the tires and they didn’t find anything. They didn’t charge me, so I’m only out the hour or two it took them to check it.
If another place finds nothing, should I still just replace the tire on the assumption that something must be wrong?
A very similar thing happened to me in my 2006 BMW… It turns out that my wheels (rims) had a coating on the inside that was flaking off. Air was very slowly leaking (like you, it would be weeks before my low pressure indicator turned on) in the tiny gap from where there was coating to where it wasn’t.
I took it to my local garage, who instantly knew what it was and said that was a very common occurrence.
They scraped the coating off, and remounted the tire. They said to expect it to happen to the other tires, and sure enough I’ve needed to do it to 3 of the 4 tires over the last 18 months. It costs about $20 (I think) each time - so very reasonable.
It could very well be that’s what’s happening to you.
I guess what the problem might be depends on whether you believe them on putting it in the dunk tank.
I had a tire with a slow leak. It lost maybe a pound a day or so. I took it to the tire shop I usually go to and told them that it was leaking but I couldn’t find any nails or anything. They said they would take a look at it and I picked it up again a few hours later. I was in a rush because I was going out of town, so I didn’t look at it real close before putting it back on the car, but I noticed some sealant around the bead.
It was still leaking though. My personal life got busy at that point and for the next month or so it was just easier to pump the thing up once a week than deal with taking it in. Eventually however I took it off and looked it over really careful and found the tiniest little hole in the tread. The tread was still pretty thick so it didn’t seem like whatever made that hole could have penetrated all the way through the tire, but I poured some water over it anyways and got bubbles.
Took it back to the tire place and explained the situation. The guy was like, oh, yeah, when they can’t find a hole they reseal the bead and that’s that. And they only charge $25 for this remounting service. Anyway, don’t discount the possibility that there is a hole in the tire.
I have had a similar problem. Turns out the wheel is corroding (slowly) and allowing air to leak out (also slowly). The tire people scrape and grind the wheel and it works for a while, but eventually I’ll have to get a new wheel (allow, unfortunately).
Corrosion on the rim mounting surface is always a possibility, particularly If you are in snow country.
A very slightly loose valve stem core or if they dismounted and then remounted the TPMS sensor as part of the tire replacement reusing the original gasket these could also be at fault.
Finally it is rare, but I have seen leaky tires.