My 2K 'Vette has a very slow RR tire leak that has been going on for about 6 months. I had the wheel checked by two different tire shops and they couldn't find any sign of a leak. It looses about five pounds a week. The valve was replaced a couple of years ago with a new one and I recently bought new tires. I tried tightening up the valve stem, but didn't want to go too tight because I don't know the torque spec for the aluminum stem. Should I reinstall the stem with some silicone adhesive? Does anybody know the torque spec or have any other suggestions?

 

Tire shop might have use the wrong wheel weight style for your tire and wheel. This would not allow a proper seal between the tire bead and the rim. This happened to my Trans Am on two different occasions.

 

curvete... I had a similar problem with a tire that would slowly lose air. I tried everything I could to find the leak using water and even soapy water. I just didn't have anything large enough to submerge a full cross section of the tire in. Then I thought about my wheel barrow (a kiddie's pool would also work).

I filled the wheel barrow with water and holding the tire and wheel upright, slowly rotated the assembly in the water. After watching the tread, sidewalls and inner rim area very carefully, sure enough, there was a leak in the rim, on the inside of the wheel.

I don't suspect that your wheel is necessarily leaking. But you need to be able to slowly rotate the wheel and tire under water, examining it carefully to find where the air is leaking from. A really slow leak might only generate a bubble or two every few seconds so do it slowly.

I would personally look closely at the area around your valve stem. Since you've change tires and not stopped the leak, it would appear to involve the wheel. I suspect that the O-ring around your sensor is leaking. Submerge the wheel and look there first. If the O-ring is leaking you'll want to replace it by removing the sensor and replacing the O-ring before you reinstall it. Air pressure should force the sensor and O-ring against the rim, so the torque on the nut shouldn't be a major factor. Hand tight using a nut-driver should be more than adequate. A bad O-ring or damage/corrosion around the hole, even on the inside, could cause it to leak.

Good luck… GUSTO

 

All the above suggestions are imperative in struggling to detect the cause of a leaky tire, AND/or, wheel. However, another source to inspect is the actual inner valve stem core. These tiny metal pressure seals are simply screwed into the valve stem itself, and, may be easily damaged producing an insidious leak. Therefore, to be sure, have the inner core replaced. This was the culprit to my slow leak last year. Good luck to you.

 

Some tire manufacturers put a small white sticker on the bead of the tire. It is made of plastic and believe it or not, despite the fact that it is very thin, it was enough to cause a very slow leak for me on two previous occasions. Maybe not every tire company uses them, but it's something to look for. If you se them there, make sure they get peeled off. HTH

 

I had a slow leak and after demound, clean rims, mount, the damed thing kept leaking about 4-5 lbs a week - - - finally checked my valve stems and found them loose - - - I snugged them up and no more problems - - - I was losing air while driving - - - when car was at rest the tire didn't lose presssure. Rotation of the tire while driving was how I came to try the valve stems.

EL

 

The valve stems with the tire pressure sensors are likely culprits. My friend bought a C5 with 8,000 mi on it and had the sensors and tires swapped from the wagon wheels to a new set of chrome 5 spoke...they all leaked like a seive....he tightened them and some of them got better but eventually he ended up having all new seals put on the sensors...which includes having the tires dismounted and the sensors removed from the rim...unfortunately the shop damaged one of the sensors while they were dismounting the tires and refused to replace it at their cost. Consider getting new tires at that point if yours are questionable.

 

A friend if mine just had this on her car. The guy who mounted the tire cut the inside lip of the tire, to the point where the air leaked past -- slow leak, about 5 lbs. a week.