Harold57

I thought that I'd start this new thread to cover some items that have been touched on in several threads over the years but never really had a dedicated thread. This thread covers leaks that are other than the obvious type leaks from punctures or blowouts.

TPS (tire pressure sensor)
The TPS have o-rings in them that should be changed every time you change tires. This was not fully understood when I first bought my car and tire shops only did it upon request. (This problem is one of the main reasons that the stickie thread exists providing instructions as to how to disable the TPS alarm, well that and the batteries going dead.) But as the TPS ages, the o-rings go bad enough to have slow leaks. If you have the o-rings replaced every time you replace the tires as preventative maintenance, you'll prevent the leaking TPS problems from occurring. (If your TPS batteries go dead, you'll just have to replace the TPS. There are other threads dealing with this and how to use Techstream to register the new TPS into its system.) Anyway, if you still use the OEM TPS, be sure to have the o-rings replaced with your tires. If you have a leak through the tire stem, the most likely cause is the O-rings in the TPS.

Chrome wheels
A lot of the Lexus OEM wheels are chrome plated. As the chrome wheels age, the chrome begins to flake and leaks will occur along the rim where the tire forms the seal. There are some shops that can fix this by removing the chrome (the shop I used called it cutting the beads). In theory, removing the chrome from the beads should eliminate the leak. It did on my wheels, though a leak started again after 1 1/2 to 2 years on one of my wheels. My neighbor has a bead breaker, so after we determined where the leak was, we broke the bead on the tire and used steel wool to clean up the area on the rim (and blew out any loose debris from the cleaning with an air hose) and the leak is now gone. That was way simpler than I ever expected it to be to rectify the problem. It's been about a week since the repair and the pressure hasn't dropped at all. (Before the repair, it would drop about 8 lbs in a week and a half to 2 weeks.)

Some wheel leaks are also caused by bent rims. If the bend isn't too extreme, these same wheel repair shops can fix the bent rim also. Cracked wheels are a different subject that I don't have experience with.

Leak finding
Some leaks are pretty obvious (like a giant bolt sticking out of the tire) but slow leaks take a little more sleuthing. In the case of the wheel leak, lay the tire/wheel on its side and pour/spray soapy water (good sudsy type soapy water) in the groove between the rim and the tire and look for bubbles that being created by the leak. You can do the same with the stem. Take the cap off and put some of the soapy water in the stem (be sure to blow it out afterwards) and look for bubbles being generated. Do it around the base of the stem also. Once you find the leak, you'll know what your alternatives are with regards to repair versus replacement.

Hope that helps. Happy driving.

mandyfig

JMTC, periodic checking of the tire pressure helps in determining potential leak issues with the tires. Of course natural leakage will occur if car is not used often, but just a few psi over long period of time. every 2 to 3 weeks you need to check pressure on all tires. Or at least do a visual.

Wilson2000

Another tire tip: About every six months (when I normally change my oil) I check my tire pressure and notice a drop of 4-5 psi. Thus, whenever I put air in a tire, I put in 2 lbs over the specified pressure as indicated on the door jam. This way, by the time I put in air again, six months later, I'm only 2-3 lbs under spec. It helps with attaining even tire wear as I'm more often running closer to spec as opposed to putting in the specified pressure, and running below spec most of the time.