I have an '07 z51 (only adding that because it's about the tires )---and a couple of weeks ago the low tire pressure warning came up on the DIC and my right rear tire was down to about 23 psi. I filled it back up to 30 psi along with the rest of them and about a week later the warning comes back on for the right rear. What was wierd to me was that even though it was obviously losing air, it would still get back some pressure just from warming up after 5-10 minutes of driving and the warning would go off. I've gone through this process again and the warning just came on yesterday. I just figured I don't know enough about run flats to tell what's going on. Any suggestions?

 

I'm having that same issue.

 

Sounds like you obviously have some type of a puncture in your tire, if you have added air to tire and it lost pressure again. As far as it "gaining" pressure after being driven, tires do that because they heat up when driven which causes the gas (air) in the tire to expand. A tire's pressure will increase 3-4 psi after being driven.

 

I recently had the same problem on my 05 w/Z51. It was not a tire puncture it was a problem with a seal on one of the rear sensors and it was leaking so they replaced the whole sensor under warranty. Good luck finding your issue.

 

I had a wheel leak on a car a few years ago. It was a cast aluminum wheel with a pin hole. It leaked so slow the dealer did not believe me. I submerged it in my pool and watched it for awhile and found the leak. They gave me a new wheel.
I get off work at 9:am and the sun shinning on the right side tires of the C6 increases the pressure a few pounds.

 

Geez, I hope you took it off the car first!

 

I had a similar problem on my 05 when I put a new set of tires put on.
They found that the right front stem/sensor was not put on tight enough. It was a little loose and the they tightened that puppy up a bit and problem solved. I think this is more common than you might think. Good luck.

 

Funny man!

Common problem guys, finnaly had a service guy tell me about this. If of course it is not a leak in your tire, or your rim, then check the Valve stem.

First off, just in case you didn't know, set your cold air pressure to 30lbs all around, yes, the normal warm air pressure will rise to about 32 to 33 with normal driving, then 35 to 36 with hard driving. That is normal. I kept running into this problem. My service guy told me that what happens around the winter time is that with the constant cold at night then warming up during the day time the bolt that holds the sensors onto the rim loosen up, so, about once every season he recommends that you get a 7/16 long socket, take off your valve stem cap, and check the tightness of the valve stem bolt. It is made of aluminum, and is very thin, so be very carefull, and do not put much pressure on it, he siad it is like 15inch lbs of tq, or just a hair over hand tight, so just use a small wratchet and put just a little tq on it to make sure it is snug. DO NOT USE A OPEN END WRENCH!!!!, The metal is so thin you will strip the bolt with an open end wrench, the socket will protect it by grabbing all corners of the bolt end. This bolt holds the sensor in place, and has a rubber washer inside the rim. I found that mine come about a half turn loose in the middle of winter!

 

I had this same exact problem on my right front less than a month after NCM delivery in August. Leaky valve stem -- a 30 minute fix at my dealership (under warranty, of course).

 

Thanks yall. I know it is normal for my tires to be gaining pressure when they warm up, but if it was a puncture I feel like it probably wouldn't get any pressure back from warming up. I'll try to check the tightness of the sensor and if that doesn't work I'll take it in.

 

and while you are at it, check the Schrader Valve. I have seen them "less than snug" and lose air.

 

It's a slow leak. It may leak 1 PSI or so per day (you know that better than I), in that case there's no reason it still wouldn't gain 2-3 PSI over a few minutes when it warms up.

Take it to a tire shop ASAP and have them find and fix the leak (hopefully it's patchable or is the valve stem).

 

Thanks hodgee, all the details are outstanding. It's just like me to overtighten things till I strip em

 

You definitely have a leak. I’ve had 3 flats (just like your slow leak) since May. So
much new construction here. Really a pain. However, I love the security of the
run-flats.

Big Jimm

“Good-bye Saddam”
Hope you took plenty of ice

 

I agree. Excellent post, hodgee.

To confirm the torque, I just looked it up in the service manual...the specified torque for the sensor retaining nut is 62 inch-pounds (2006 Helms manual, Vol 1, page 3-94)

I hope every one understands that an INCH-POUND is not the usual torque wrench increment of foot-pounds. If you're using an eight inch long rachet handle, you can figure you only need about seven pounds of force on the end of the ratchet handle (8 inches X 7 pounds = 56 inch-pounds)...Err on the side of less force/torque to be safe. Better yet, use a small micrometer torque wrench graduated in inch-pounds.

 

Put a little soapy water around the valve stem and if it bubbles that's the leak. If not you have a nail or screw in the tire somewhere.

 

First thing to check is to make sure the nut on the valve stem is tight.