Slow tire leak... valve?

RatLabGuy

RatLabGuy

You look like a monkey and smell like one too
Joined
May 18, 2005
Location
Churchville, MD
Wife's 08 Pathfinder has a tire that chronically loses air.
It's very slow - like a couple psi per day at most. I top it off every couple of days, even if forgotten for a week it only gets down to like 22 or something.
No nails that I can find. I replaced the valve stem core, no change.
Tried soapy water, no bubbles, even inside the valve. But so slow, not sure I would.

Only thing I can think is, the stem has some minor distortion or crud in it that is juuuuuust enough to let a little out.
Any suggestions?
I'll probably just take it to the neighborhood tire place and have them replace the valve stem, but due to the damn TPMS cost that's kinda pricey as a shot on the dark.
 
The rebuild kits for the TPMS stems are only a few bucks. It's probably corroded around the rubber seal or something. I generally replace them every other set of tires on something that has them.
 
If you know someone with a small kiddie pool or small round stock tank, submerge it and see what happens. Even if the leak is very slow, some small bubbles will cling to the tire/wheel/valve around the leak area after a while.

But yes, always suspect the valve stem first, especially if they haven't been changed for a while.
 
Make a 2:1 mix of water and liquid dish soap, put it in a spray bottle, and spray it all over the wheel and tire. Observe and listen. You will find it if it is losing a couple PSI/day. Another thing is to spray all around the base of the valve stem and then bend it around. I had one that was cracked, and would only let a noticeable amount of air out when you pushed on it. I think accel/decel or rotation forces were causing it to gap slightly and leak down, but it would be almost non-existent if it sat for days.
 
I got a leak on one of my dump truck tires that is similar. I have to pump it up every morning. I can hear it leaking but can't pinpoint the source and soapy water has done nothing to help.
 
YotaOnRocks said:
I got a leak on one of my dump truck tires that is similar. I have to pump it up every morning. I can hear it leaking but can't pinpoint the source and soapy water has done nothing to help.
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That sounds like it is blowing so hard it is not forming bubbles. Try a thicker mix maybe? Or if you can take the tire off and put it in a giant tub of water. You have a creek, right?
 
jeepinmatt said:
That sounds like it is blowing so hard it is not forming bubbles. Try a thicker mix maybe? Or if you can take the tire off and put it in a giant tub of water. You have a creek, right?
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I do have a creek, I bought a new oring for the wheel and a rebuild kit for the valve stem assembly but haven't wanted to break the tire down since I can't pinpoint the issue. Well that and I'm still recovering from the last time I wrestled those 49's around.
 
Yeah I've tried the soapy water thing multiple times wo luck.
The valve stem is a type that has a nut on it threaded down so its locked into place. Cant really wiggle it.
I *think" this is the only tire that has the original stem, it's an 08 model we got from the original owner and according to my notes all the other tpms units have died or gone bad since we've had it. If that's true it's pretty suprising the thing still works.
 
I use regular ol’ windex. Check the bead area front and back as well. Make sure it’s pumped up to max.
 
Years ago I had a tire with a slow leak, couldn’t find a hole anywhere. Turns out the wheel had a small crack that would only leak after the brakes heated the wheel up. It wouldn’t leak cold.
 
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