Slow leak in tire--replace all 4?

One of the tires on my 2008 Legacy GT has a slow leak, and it has gotten worse enough in recent months that I'm to the point of taking some action.

Previously, the leak was slight enough, maybe 1 psi/wk, that I didn't bother with it. I've had the tires rotated, and always been one specific tire. I had the dealer test it in a water bath to find the leak, but they couldn't identify it at that point. I've driven about 8K miles since then though, and now it's leaking enough to trigger the indicator light every week (so maybe 7 psi/wk).

So now my I'm wondering whether I need to fix this by replacing all four tires. My tires have about 35K miles on them, so I suppose they have a decent amount of wear, but the mechanic said they had some life to them at my 30K maintenance. Should I just bite the bullet and replace them all? Or do I have other options?

take it to a tire shop, like bf goodrich or some big tire shop and they should be able to fix it for under 20$ unless its something serious. but by the sound of it its not. probably a nail or something. its worth a shot what do you have to loose compared to a couple hundred??? GL

If there's a leak, someone competent should be able to find it. Air doesn't just disappear. Have someone else check it over again, carefully, if you're sure it's the same tire. And plug it up, if it's in the tire itself. Or replace the valve stem if it's leaking from there. Either way, someone should be able to do something other than what the dealer did.

check the valve stem and wheel for leak

Originally Posted by CapitanG

One of the tires on my 2008 Legacy GT has a slow leak, and it has gotten worse enough in recent months that I'm to the point of taking some action.

Previously, the leak was slight enough, maybe 1 psi/wk, that I didn't bother with it. I've had the tires rotated, and always been one specific tire. I had the dealer test it in a water bath to find the leak, but they couldn't identify it at that point. I've driven about 8K miles since then though, and now it's leaking enough to trigger the indicator light every week (so maybe 7 psi/wk).

So now my I'm wondering whether I need to fix this by replacing all four tires. My tires have about 35K miles on them, so I suppose they have a decent amount of wear, but the mechanic said they had some life to them at my 30K maintenance. Should I just bite the bullet and replace them all? Or do I have other options?

IIRC, doesn't tire pressure go down with every 10° drop on temperature?

I had a similar problem on my '02 Impreza....turned out the air was leaking out through a pin hole in the rim itself....Subaru gave me a new rim.....make sure whoever you have check it looks for that possibility.