I have a slow tire leak; I fill to the recommended cold pressure and then it leaks over time (days, not sure how long) and loses about 20% of pressure and then stops leaking. It seems to hold this level of pressure for longer periods. Other tires are fine.

The tire shop said the valve stem was lose and tightened it down. But that's now been done a few times and it's still leaking. What get's me is that the tire pressure seems to stabilize at some point.

I'm not sure if the valve stem is the original or if they replaced it when I bought the tires. It's about 15 years old if original; about 3 years old if replaced w/ the tire.

Any thoughts? I'm thinking about having the shop rotate in the good wheel (5 wheel rotation - AWD truck) and take the bad wheel off to troubleshoot.

If valve stem, should I replace w/ factor OEM (denso?) or just whatever the tire shop carries (it's all the same)?

15 yr Alloy rims can leak at the bead - Best to let them test it again - I had one like that and I that never got fixed -

Thanks. Okay, I’m going to have them rotate the good tire back in. I’ll pull the other one for now and take it to get checked when I have more time.

I had a tire doing that on the Jeep. Turned out it was a leak around the valve stem due to corrosion. They sealed it up and it stopped doing it. They warned me it was only a matter of time before another started doing the same--or I started getting rim leaks for the same reason.

Sure enough: Eventually one of the other tires started doing the same.

Finally had all the wheels replaced last fall when I had new tires put on.

Ironically: One of the old tires had a nail in it. That was not the one losing air either time.

I have seen tires that leaked only when parked with tire in a certain part of its rotation. A small leak that only opens up some times.

Jiminy. I hope I don't have to replace all wheels. That would be very expensive.

I try to do a good thing - AWD 5 wheel rotation. I put a tire on the spare that had probably been sitting under the truck since new (I think still had original factory tire) and put it into rotation as recommended.

Been annoying ever since.

It's a good thing and I know it's the right thing to be doing. Just wish I wasn't having this issue.

Wheel corrosion would be my guess.
My 2014 Tundra wheels have started to corrode. One is pretty bad. Won’t go flat or too low to drive safely but am filling it up every few days.
With temps around 0 for the last week it has been even worse.

You can have them lightly sand the corrosion around the bead area and that should help.

My Silverado was real bad and I needed tires. Thankfully take off Silverado wheels are a dime a dozen on FB. $500 for brand new wheels and tires and sold the old ones for $100.

Thanks - is there a recommended way for the shop to troubleshoot this so that they actually find the cause? Or is it gonna be trial and error? I assume this is not an unusual problem - they will just address the most common issues for something like this and go from there?

quote:

Originally posted by konata88:
Thanks - is there a recommended way for the shop to troubleshoot this so that they actually find the cause?

Fill it up, dunk it in a tub of water, look for a thin stream of bubbles. That's the only way of which I'm aware.

I had a set of styled steel factory wheels on a Mercury Cougar back in the day. We sanded the bead area down and applied s skim coat of clear silicone. All four wheels held air for at least 6 years when I sold the car.

quote:

Originally posted by ensigmatic:

Fill it up, dunk it in a tub of water, look for a thin stream of bubbles. That's the only way of which I'm aware.[/QUOTE]

This. Put 60 PSI of air into it and then submerge it.
I used to work at a service station and fixed hundreds of tires.

My Grand Prix had alloy wheels and gave me the same problem you described.

After the dunk in the water test, the tire tech dismounted the tire and showed me some light discoloration/whatever it was along the wheel rim where the tire seals to the rim.

He cleaned it off with a wire brush, wiped it with acetone, let it dry, then applied some of what he called "bead sealer" with a brush, let it dry, remounted the tire, and it was fine for many years after that.

I don't live where road salt for snow and ice is a routine just about everyday use to clear the roads. That stuff rusts out cars like crazy. I don't think you do either.

The other thing I've had happen was valve stem air leakage. Either the valve stem is bad where it seals to the rim or is cracked somewhere, or the valve stem core is not tight and is leaking. Everybody should own a $3.00 Valve Stem Core tool, it just screws in and out the valve stem core. You can just make sure it's tight yourself. You can get any spray bottle and fill it with a soapy water solution, spray it, and see if you can find air coming out. Sometimes the leaks are bad enough to see, sometimes the leak is so small and slow you won't see it that way.

If I were you, I'd take it to a well reputable tire shop and have them pull the wheel off the car, dunk it for observation. Then pull the tire off the wheel to inspect the meeting surface. And have the valve stem replaced with a new one. (Rebalancing the tire/wheel at this time is a really good idea)

Best wishes to you, good luck.
.

I've run over nails and the head wears of quickly and the end is very hard to see if it's in just the right spot.
The resulting leak was also very slow.
I'd do the submerge and look for bubbles test and maybe even have the tire dismounted so you can look inside.

I had an old beater Tundra that somebody had put aftermarket chrome plated wheels on. One day I went to go someplace only to find the right front tire flat. I figured I had picked up a nail or something. Called AAA to come out and change the tire for me, then a couple days later took it to the tire store. No nail. Nothing wrong with the tire at all. THey said the chrome plating on the wheel tends to corrode over time, and eventually the corrosion built to the point that the bead broke and the tire went flat.

They took all four tires off of the wheels, cleaned up the corrosion around the beads, remounted the tires, and didn't charge me a dime. Even so I never completely trusted them after that, and a few months later (before starting a 3000 mile road trip) replaced all four wheels with new aluminum ones. Then wound up selling the truck a few months after that, for other reasons.

Be glad it is a slow leak! This got me in the company car a couple weeks ago doing about 90 in quite the downpour headed to a house fire.
Luckily it was the rear and I was able to control it.
If it was in the front would have been a different ball game.

Often the rim leaks are too slow to see a stream of bubbles in a tank. Spray around the rim with a concentrated soap solution. 409 or something like that. Watered down dish soap works well too. Then wait for a foamy area to appear. This works best with tire laying flat on the floor. Remember to check both sides of the rim.

^^^
This or a spray bottle with a light soapy mix.

I had something similar that turned out to be a very small shard of metal that was not easy to find with the naked eye. It would drop tire pressure until internal pressure dropped low enough that it couldn’t force its way out anymore.

Thanks guys. I filled it to recommended pressure. I’ll check it daily to see how fast it’s leaking. Then I’ll have the shop swap it out.

I’ll try to figure out where it’s leaking and then have the shop fix it. I’ll check both beads and the valve stem.

quote:

Originally posted by ensigmatic:

quote:

Originally posted by konata88:
Thanks - is there a recommended way for the shop to troubleshoot this so that they actually find the cause?

Fill it up, dunk it in a tub of water, look for a thin stream of bubbles. That's the only way of which I'm aware.

Doesn't always work. Sometimes the tire needs to "flex" to have the leak. Had a slow leak in one of my tires (~1 month for idiot light to come on) brought it in to shop, did entire tire with spray bottle with soap, nothing, completely submerged in water, no bubbles.

Wound up pulling tire, polishing bead and remounting tire. Has held now for ~6 months with no issue.

Good to know. Thx.