Valve Stem Caps
Thread Starter
Safety Car
Joined: Nov 1999
Posts: 4,292
Likes: 1,165
From: Green and Wet Western Oregon
2023 C7 of the Year Winner - Unmodified
2018 C6 of Year Winner
Valve Stem Caps
If you have valve stem caps with a rubber o-ring you might want to think about removing the rubber o-ring. It is a minor inconvenience, but can (and did) cause flat tires. The rubber o-ring became lodged in the valve stem releasing the air. Three of our run-flats were down to 10-15 lbs and the fourth was at zero. I just popped the o-ring out with my pocket knife, aired up the tires and all was well.
Thread Starter
Safety Car
Joined: Nov 1999
Posts: 4,292
Likes: 1,165
From: Green and Wet Western Oregon
2023 C7 of the Year Winner - Unmodified
2018 C6 of Year Winner
They were in the correct position when I installed the caps, but like I said they became lodged in the top of the stem and released the air. It may have something to do with the style of metal valve stems on my wheels, but I'm not taking any chances, I just removed them.
Le Mans Master
Joined: Sep 2003
Posts: 8,812
Likes: 2,029
From: eastern NC
Originally Posted by duckvett
...The rubber o-ring became lodged in the valve stem releasing the air. Three of our run-flats were down to 10-15 lbs and the fourth was at zero. I just popped the o-ring out with my pocket knife, aired up the tires and all was well.
Something similar happened to me. For some reason they use an o-ring while much less expensive caps use a small plastic flat washer. The o-ring/flat washer does help to keep these caps tight so they don't vibrate off, so I just removed a set from some less expensive caps and installed them.
I have similar caps on a couple other cars and the o-rings don't slip down into the stem like they do on the TPS valve stem. I think it's just a problem with those valve stems.
Good luck... GUSTO
Race Director
Joined: Dec 2000
Posts: 19,304
Likes: 85
From: San Diego CA
I mentioned to another C5 owner that I had a veeeeery slow leak in one of my tires. He told me to check the valve stem cap sealing ring, which can press against the valve and cause the leak. I removed mine and sure enough, the rubber seal was sticking up higher than normal. I pushed it back down and all has been well for the last week.
Although I won't go as far as to recommend that everyone remove the seal, but I will say that everytime you check and/or add air to your tires, you should check the cap seals to make sure they are seated correctly.
Although I won't go as far as to recommend that everyone remove the seal, but I will say that everytime you check and/or add air to your tires, you should check the cap seals to make sure they are seated correctly.
