I just had new tires put on my 99 vette and I am losing air from somewhere other than the tire itself. It has been checked for leaks repeatedly and I replaced the valve without solving the problem. Can the stem have a leak in it somewhere and if so, can it be replaced without buying a whole new sensor? We all know how expensive the sensors are. The sensor remains to work. Any help would be greatly appreciated.


[Modified by STLBLUE75, 4:54 PM 8/15/2002]

 

I obviously don't know if you have stock valve stem caps or not. Some after market caps have "o" ring seals in them that can cause problems if the caps are overtightened and the seals come into contact with the valve core, depressing it and casuing air to escape. Or, the "o" ring seals can be lost from the inside of the caps. Were this to be the case and you had a loose, defective, bent or leaking valve core, the cap(s) with the missing seal(s) would not prevent air from escaping. I've seen so many different types of stock valve caps on the different year models that I don't know what type of seal they have, if any. Also, I would check the valve cores with a valve core tool to make sure that they are tight, but not over tight. and straight (not bent). Also, you may want to check the valve cores to make sure ones of proper length were installed back into your valves. Many times tire shops will completely remove the valve core (as they should) to increase the volume of air going into the new tire during initial inflation to facilitate seating of the new tire bead to the rim. Then the core is reinstalled and the tire inflated to the proper pressure. If the tech has a bunch of valve cores lying around of different lengths, it could be easy to install the wrong one. Just some ideas and stuff to check. But I have found that valve cores leak a lot more often than people think that they do just because they get loose in the stem or were not properly tightened when reinstalled or have become bent after tire service. Good luck.

 

Spray some soapy water around the base of the stem at the wheel. Some shops take the stem/sensor out of the wheel while changing the tires and them put them back in after the tire is on the wheel. There is a rubber O ring to seal the sensor to the wheel. If the O ring is leaking you'll see bubbles in the soapy water. The tire will have to be pushed off the wheel bead and the sensor removed to put on a new O ring.