Slow Leak

[Velocity]

Ok all you tire experts - I recently replace my runflats with Yokohamas and have a very slow leak in one tire. I brought it back to the shop twice but they could not find the problem. Did the water check and soaped it up and still no luck. :( Any ideas? Bent rim maybe?

[Lexusfreak]

Possibly a bent rim, but you should have seen results on the "water" test. Another possiblity could be that the tire wasen't "sealed" correctly to the rim when it was installed. My dad had a slow leak in one of his tires.....took it to 3 places & finally it was an extremely small staple that you could hardly see & the hole was the size of the smallest pinhole of all things.....had it patched & good as new! Don't be afraid to take it to another tire place to get it checked out. How much air are you loosing? & how often are you checking the pressure?

[jimbostar]

Also check the valve, you can either replace/tighten just the valve needle (it screws in) or replace the enitre valve if this is the problem. When you do a water test, take the valve cap off and move the valve around with you fingers.

[Lexusfreak]

I agree, examine all possibilities to figure out the problem. B)

[steviej]

was the water and soap test done with the tire off the car?

I had an instance once where I needed the weight of the car on the tire to make the leak appear. The weight of the car distorted the tire enough that the leak became evident.

Pay particular attention to, as mentioned earlier, to valve stem. Take the cap off the valve stem too to inspect the metal push pin. Sometimes the plastic cap on the stem is enough to make the water test look like there are no bubbles but over a 24 hour period, enough air escapes here to flatten the tire.

Try the soap thing again with the tire on the car if previously off the car.

Last ditch effort:

I read once in an auto repair column once that someone once filled the tire with a UV dyed gas or air, like they do with AC systems and then looked for the leak under a black light.

good luck.

steviej

[VBdenny]

I like the black light check, sounds interesting. I would agree that you need to take a good hard look at the valve stems. You can replace the stem easily, but you need a stem removal tool (less that $5) and a new stem (really cheap). I have had them leak sometimes and not leak others.. When I was younger, I worked in a gas station and repaired many a flat tire. Most leaks were because something like a screw or nail, but I saw pieces of metal, coat hangers, and once a 3/8" ratchet stuck in a tire. When all of those possibilites are null, it is usually the valve stem. If you relace that, there is only one thing left that can leak, the bead seal. When tire guys put tires on, the are suppose to lube the bead. I've seen more than one that doesn't and then you can have a problem. I never saw a leak that couldn't be fixed that wasn't sidewall damage. One the sidewall is punctured, the tire is done.

[Lexusfreak]

Did you get it fixed yet velocity?

[Velocity]

Yep! After three trips to NTB it finally turned out to be a bad valve. I guess they just didn't take the time to check everything out earlier. BTW, I learned that the valve on the SC430 is part of the tire pressure monitor. Who knew?

[Lexusfreak]

Glad it's fixed! So because of the bad valve, your tire pressure monitoring system was not registering correctly? Thought Lexus would have put a warning light in the car for something like that.