Slow Leak, wha do you guys think could be the cause?
 

So last Friday I had gotten some new tires put on new wheels. 30 minutes after leaving the tire shop, my TPMS light came on. Called the shop and they said bring it by. Went by in the afternoon and they checked all 4 tire pressures. 1 of the 4 tires (driverside rear) had 25psi and the other 3 at 35 psi which is where it should be inflated at. They inflated the wheel back to 35psi and TPMS light when off. Thought the issue had been resolved. 30 minutes later driving home, TPMS light comes on again. I get home and check all 4 tire pressures and the same driver rear tire has lost about 15psi. I reinflated the tire to 38 pounds and left it at that over night. The following morning i check the tire pressure on the one tire and it held fine. I get on the freeway to go to work and 8 miles into the freeway, the TPMS light comes back on. I get to work and check the pressure on that same tire and has it gone from 36psi to 21psi in a 20 minute driver on the freeway. After work i fill it back up to 36psi and drive home locally. Got home and checked pressure again and it held fine at 36psi. I repeated everything again the next morning and same result.

I have concluded that the slow leak is only leaking mass amount of pressure when tire expands at high speeds due to heat. However, i can't pinpoint whether it is the beading between rim and tire, valve stem itself, or maybe the TPMS sensor????? Possibly the rubber gromet on the TPMS was pinched and causing slow leak???

i'd like to hear some of your guys input based on your experiences. although i definately will be going back to the same tire place i got my tires at to have them take a fix at it.

thanks

Some tires just leak. The rate of you leak suggests something abnormal but you may never find it. Try a small amount of fix a flat, make sure you purchase the fix a flat that is TPMS safe. Put it in the tire then drive the car right away so it coats the inside of the tire and doesn't pond. My new tires (on a honda element) leaked a bit and this solved it.

Rubber grommet on tpms would be my guess as long as they didn't damage the sensor itself.

wouldn't really call it a "slow" leak then huh

Make a bucket of very soapy water. Take the wheel off the car and douse it with the water. Even a slow leak should make fine bubbles. You could check just the valve stem without taking the wheel off, of course.

i did take it to 2 other tire shops more local to me and both shops sprayed soapy stuff on valve stem area and no bubbles or signs of leak. Also one of the shops did take the wheel off and dump it in the dump tank to look for bubbles and found nothing.

Check the shrader valve and tpms for tightness. It has to be related to the valve.

Some manufacturers put tiny stickers on the beads of the new tires. Worth a shot to spray around the bead to make sure there are no leaks there. They can be very very small.

Dunking the tire isn't going to reveal anything. Take tire off, spray with soapy water, then leave for 5 minutes and come back. The bubbles will reveal the leak.

thanks everyone, will try everything mentioned above!

I had the same problem with a 1982 Toyota Celica when I bought it new. After several trips to the dealership they found a faulty wheel.

i went to do a double check on the tightness of the tpms sensor. Just so happened to be, the wheel i was losing air pressure was really loose. I got a 11mm wrench and gave it a few turns and went for a 30 miles drive to come back to exact same tire pressure. So problem solved. Just in case any one might encounter a situation like this in the future, check the valve stem and where the TPMS sensor is bolted down too.