Tire losing air in an odd way?

dra2120

Active member
I need some help figuring out what is going on with my tire. A couple of weeks ago It started constantly losing air, but in some very odd ways. I fill it up to 40psi (a normal pressure for the tires), and within a day it is down to 30psi, then it only loses about 2psi every day after. For the most part it really only seems to lose air when it is parked. I did a 4+ hour drive yesterday and was watching the tire pressures on the infotainment screen, the PSI stayed very steady the whole time I was driving, but anytime I would stop for longer than a red light it would be down 1-2psi. Also, about 75% of the time I go to put air in it, it won’t take air. I have a compressor that you can set your desired psi, and it will shut off at that pressure. So about 75% of the time it will shut off within 1-2 seconds of turning it on saying the tire is full, even though it is still quite low. I have tried it on other tires, and it only does that on this one tire. I typically have to remove the valve core and re-install it before it will take air. It lets air out fine, any push on the Schrader valve will allow air to come out, but it won’t let the air in. I’ve checked the tire for nails/holes and haven’t found any, I’ve replaced the valve core twice, and put slime in it, but the problem is still there. I’m wondering if the TPMS sensor has some sort of check valve that has failed, but I really kind of stumped on this one.
 

workerdrone

Part time fulltimer
Sounds like replace the valve, I'm not familiar with TPMS does that mean an expensive valve? My only vehicle with TPMS uses regular valves and a read off the wheel speed to warn about tire pressure.
 

WeLikeCamping

Explorer
I had that problem with my SxS after a Firestone tech installed new tires and valves (NEVER again, Firestone!) I'd go for a ride and all would be fine. Let it sit overnight and it would go flat. Kept messing with it and finally figured out that the valve stem itself was leaking. Took it to Discount, had a new valve stem installed, and no more problems.
 

NatersXJ6

Explorer
Agreed, valve core is malfunctioning somehow. First I would just tighten it and see if that makes a difference. They are less than 1.00, so just replace it, no big deal.

also, verify you are actually losing pressure, not that TPMS is just reading incorrectly.
 

dra2120

Active member
Not enough info.

How are you measuring tire pressure? TPMS, or a gauge?
Measuring with an old fashion stick gauge, with my air compressors digital readout, and with the TPMS system
Try some soapy water around valve stem to reveal leaks.
I think that is the next step.
Agreed, valve core is malfunctioning somehow. First I would just tighten it and see if that makes a difference. They are less than 1.00, so just replace it, no big deal.

also, verify you are actually losing pressure, not that TPMS is just reading incorrectly.
I've replaced the valve core twice already, and it is definitely losing air...Like others have said it sounds like the valve body itself may be bad.
 

Betarocker

Adventurer
Soapy water everywhere. Inflate the tire to maximum on sidewall. Use a spray bottle and mix a solution of dishsoap and water. Spray the valve area first. If no bubbling, spray the beads, both sides. Spray the surface until you find bubbles.

Another way if you have a large storage bin large enough that the tire touches the bottom. Fill with water at least the depth to submerge the tire sidewall and rim to the spokes. Put max inflated wheel/tire in the water and rotate until air bubbles are seen.
 

broncobowsher

Adventurer
Fill to 50 PSI, dunk in a water tank. If no dunk is possible, soapy water spray.

I've had leaks that didn't leak at low pressure, but would leak at high pressure. The leak is like a pressure relief valve.
I've also had the opposite. Tire would hold air for weeks and one it reached a point it would just go flat in hours.

Air is getting out. Until you find where it is leaking, everyone is just guessing. I've seen too many different leaks over the years that are not typical. Steel wheel leak through a weld. Porous casting, bead leak, valve stem. Even a lightening strike arced through the belts.
 

alanymarce

Well-known member
If you haven't already done this, I suggest taking the tyre off the rim, cleaning the rim (and checking for cracks/damage), clean the tyre, put it back on and see what happens. Could be a poor seal, which occurs only some of the time.
 

DaveInDenver

Middle Income Semi-Redneck
The valve stem TPMS sensors have rubber seal, grommet and retaining nut seal probably has just loosened or hardened. There's a seal kit to "rebuild" them that tire shops should have. But it's possible for them to corrode or crack so the body can leak. The dunk or soapy water test will tell you something.
 

dra2120

Active member
What did you ever find as the leak problem?
I haven't had a chance to look yet...The weather around me has been either in the single digits or snowing for the last week or two...I'm waiting for a warm day to go check it.
The valve stem TPMS sensors have rubber seal, grommet and retaining nut seal probably has just loosened or hardened. There's a seal kit to "rebuild" them that tire shops should have. But it's possible for them to corrode or crack so the body can leak. The dunk or soapy water test will tell you something.
I just found the rebuild kits your talking about, I'm about 90% sure that is the problem. Once the weather warms up a bit, I'm going to hit the tire with the soapy water and see what I can find.
 

Forum statistics

Threads
185,527
Messages
2,875,534
Members
224,922
Latest member
Randy Towles
Top