2015 Subaru Forester Slow Tire Leak

And the reason you don't just take it to the local tire shop is....

There could be two problems, only one of which involves the valve stem.

Do you have a large washing tub and a water hose? Even easier, how about soap, water, and a spray bottle?

replying to Wade Garrett, LD1988 wrote: Because I want to try to fix the problem myself first. To use your turn of phrase: The problem with that is...? I'm just looking for some friendly advice here, thanks.

If you carefully inspect the tire, including inside the treads to look for nails (they can hide, like wearing off their heads so just the stem is sticking into the tire), have any roads you drive on be repaved with those damn stone chips aka chip-seal?

I've had a stone chip get wedged into the tire inside the tread. Couldn't see it from the outside. Worked its way to inside. Tire had to be removed and a patch applied inside.

Just because you cannot see the projectile in your tire doesn't mean there isn't one. Apparently I spun my tires so hard with a V8 and soft compound tires that a bolt got lodged into a tire. Not bolt end first but head end. That's right: the bolt went into the tire head first. I couldn't even see the end of the bolt when inspecting the tire. Saw the head sticking inside when they dismounted the tire from the wheel. I could understand how nails and chips might get skewered into a tire but this was a big bolt and head first.

Mix up a solution of water and dishwashing liquid and brush it on the the valve stem body and nozzle. If that's not leaking, brush in on the rest of the tire including the rim. Inflate the tire to 45 psi first. Happy hunting!

Or you could've just gotten a tire pressure gauge. They cost maybe only a couple of bucks at the hardware/automotive store for the analog ones, maybe a few bucks more if you get a digital.

I wouldn't call a 3-4 day leak to be a slow leak, that's actually a pretty fast leak. I have a tire that leaks slowly over the course of 1 or 2 months! It used to leak every month, but then I got it fixed, and now it only leaks every 2nd month.

It could've been the valve stem, but it could also have been a poorly fitting bead around the wheel rims. The standard thing to do here is to coat the tire in a soapy water solution, and then watch to see if bubbles start popping up around some part of the tire. If it does, then that's the source of the leak. In my case, that's how we found that it was the rim to bead interface that was leaky.

It's not unlikely that the valve was also slightly loose therefore it improved the leak time by replacing it, but the real source is elsewhere.

I would never take a problem like this to the dealer, as it's too expensive there. I'd go to a local mechanic instead for this.

Yousuf Khan

Because: It's a hump to do; requires specialized equipment to properly diagnose; requires pro equipment if the bead needs to get broken, the tire removed from the rim, reinstalled and re balanced; a new valve stem and/or TPMS device is needed; tire/wheel work is "dirty," unsatisfying, and unrewarding work which is usually dumped off on the lowest skill new guy in a general repair shop; tire shop grunts are usually a click and a half below the quality of regular repair shop grunts; it's very time consuming; and you're probably looking at a max charge of $25 for a half-hour while-you-wait repair at the tire shop.

That's why;-)

But hey, you wanna do all that, knock yourself out!

Put the wheel in a tub of water and find the bubbles.

Don't inflate to 45. Not that it's not safe, but at 45 it may very well not leak if it is a bead leak, while it may leak a lot at 35 or less.

That's a good point. Apply soap solution to check the rim/bead seal. If that's OK, increase the pressure and test the rest of the tire tire.