Finding extremely slow tire leak

[Captain Spaulding]

I have one that is driving me crazy.

Tire placard on the vehicle says 35psi. Tire loses 4-6psi in a month, whether parked or being driven. This is accounting for temperature related variation.

Things I’ve tried:

Multiple close inspections of the tire, including the sidewalk, and rim for any indication of a puncture, cut or object in the tire.

Sprayed tire, rim, bead and valve stem with soapy water.

Increased pressure to 45 psi and soaped it again.

Immersed the tire in water at 45 PSI, 35 PSI and 20 PSI.

Sprayed the tire, rim, bead and valve stem with Windex just for the hell of it.

Swabbed the tire, rim and valve stem with a very soapy mix with water.

Replaced the valve core in spite there being no indication of a leak there.

Broke the bead on the tire, wiped both the bead and rim down and re-inflated.

This is driving me crazy. Tires have 5000-10,000 miles left on them and I’m considering replacing them to see if that fixes it. I am not optimistic.

I’m checking every time we drive the vehicle, and it’s normally down 1 psi from the other three per week since I last inflated it to 35. Of course, it eventually starts dinging at me, usually when I’m in a hurry.

Any ideas?

 

[Half-fast eddie]

Looking forward to thevanswer. Wife’s odyssey loses a pound a week.

 

[Captain Spaulding]

Looking forward to thevanswer. Wife’s odyssey loses a pound a week.

Maybe I should add this is a 2004 vehicle that I’ve owned since new that has never exhibited this problem before.

 

[Wrench97]

Is there a TPMS sensor in the valve stem on this wheel?
Aluminum or steel wheels?
Aluminum wheels corrode around the bead and around the valve stem, you also have to look for tiny cracks.

 

[Copymutt]

Are u submerging the wheel also?

 

[snyder]

I have one aluminum oem wheel on my jeep that leaks slowly. When sprayed with soapy water it would foam along the bead but not bubble. I finally layed the wheel on the ground and slowly poured soapy water on it instead of spraying it..

 

[Rst277]

Maybe I should add this is a 2004 vehicle that I’ve owned since new that has never exhibited this problem before.

Why drive yourself crazy? Put some of that green leak sealer in there and forget about it. 5 minutes, $10 - easy.

 

[PoorUB]

My bet is is the tire bead leaking on the rim. You demounted it. What was the condition of the rim?

I will take the tire completely off the rim, clean the rim with a wire wheel and the tire bead with a scotch bright pad and water and put it back together. It always takes care of the slow leaks.

My wife's car had a bead leak. I took it into a tire shop. They brought me in to show me how bad the rim and tire bead was. (It wasn't!) They insisted on selling me a tire. I asked them if they ever wire wheel rims, and scrub down the tire beads with scotch bright? They got kind of quiet and said, yes fairly often. I told them that should do it! They cleaned the rim and tire up and I ran that tire for a couple more years with adding air a couple times. Before I left the shop I mentioned I worked in a shop that sold tires for a few years.

Pretty sure they pull that stunt often and get customers to buy tires.

 

[garfunkle24]

Could be permeating through the tire but most likely a minor ding or scratch in the wheel right at the bead.

 

[Wiz02]

I had a slow leak in 2 Oem tires on Oem wheels. Dealer finally dismounted the tires and applied some kind of bead sealant. Not only did it fix the slow leak, but when I replaced the tires, I didn't have a slow leak again.

 

[Zeke]

When you submerge, how much of the inner rim is under water? Bead leaks are fairly common on older alloy wheels but they also can leak anywhere spokes attach. If that's the case. it's a stress crack and time for a new rim.

 

[Busted_Knuckles]

When this rolls into the shop, we dismount, clean the rim seating bead surface with a large wire wheel on a 9" grinder, clean the rubber bead of the tire, and then apply bead sealer to the rim on both beads mating surfaces, as well, change out the valve stem with new, valve stem is also lathered with bead sealer. This almost always fixes a slow leak, or at least it should be done, if youre looking for a permanent solution.

If the rim is aluminum, then likely a different rim or some kind " Slime " liquid sealer if the above procedure does not fix it. Just note, the next time you go for tires, the next guy is not going to be happy with you, if you use a Slime kind of product.

 

[Mick56]

Several times I have found leakage where the barcode sticker is on the tire bead. I scrape the sticker off with a razor blade to fix that.

 

[Merch1]

Looking forward to thevanswer. Wife’s odyssey loses a pound a week.

I wish I could lose a pound a week

 

[no704]

Evacuate the tire, fill with hydrogen, check with a lighter.

 

[unslow1]

Evacuate the tire, fill with hydrogen, check with a lighter.

I can't believe you would suggest using a lighter. That is so unsafe. He could easily burn his fingers or thumb trying to hold a lit lighter that long.



Use a propane torch.


OP have you tried submerging the tire overnight?

 

[PCustoms]

I had 2 takeoff tires in the garage I had saved for a trailer project. Went to roll them out of the way last week and happened to notice the head of a nail in the tread.

Felt inside and could feel where it pierced, but just a bump. Oddly found a nail shank, no head, laying on the floor too. Have to think it was poking though a good 2" then rusted off.

As far as I can remember this tire wasn't loosing air.

Good luck!

 

[Joemctag]

Several times I have found leakage where the barcode sticker is on the tire bead. I scrape the sticker off with a razor blade to fix that.

They don’t take the stickers off????

 

[Captain Spaulding]

Is there a TPMS sensor in the valve stem on this wheel?
Aluminum or steel wheels?
Aluminum wheels corrode around the bead and around the valve stem, you also have to look for tiny cracks.

Aluminum with TPMS. Bead and valve stem thoroughly checked.

 

[rancherbill]

I put some of the slime / goop / tire stuff in the tire. I seem to recall several years ago, someone put 5 or 6 oz of dish detergent in their tires for leaks.

 

[Captain Spaulding]

When you submerge, how much of the inner rim is under water? Bead leaks are fairly common on older alloy wheels but they also can leak anywhere spokes attach. If that's the case. it's a stress crack and time for a new rim.

I held it down in a cattle tank with both hands so it was fully submerged. Flipped it and repeated. Not a sign of a bubble from anything.

 

[ChevyEFI]

45psi and I dunk it in the pool.
Soap is too much work.

My last was 5-10psi / day loss while 3 hours from home last week. And the tires are < 2mo. old. Gotta love forest road trash. It's patched now.

 

[mark#3]

There is bead sealer you could put on the rim, it could leak anywhere on the tire, tires are not made as good as they were years ago.Valve stem could be leaking.
Aw, he already did what I said.

 

[Squankum]

My only useful advice is to check the tire tread outside in bright, direct sunlight.

A full dismount and sunlight inspection and new sensor/valve, remount?

Or.... fill with water and add some pressure?

 

[cmandp]

Is this an aluminum wheel? If so it's likely cast and could have a small pourous spot leaking air. My brother in law's Subaru had a couple aluminum wheels with a pourous casting.

 

[dchawk81]

I wish I could lose a pound a week

Wish the wife would lose a pound a week.

 

[Milton Shaw]

Make sure there are no bends in the rim at the bead area. I have a friend that had one, leaked only when driving and bead flex and let a very little bit out. Replaced rim and no more leaks. I had soaked tire and rim over an hour an never found anything leaking.

 

[cvairwerks]

4-6 psi a month is essentially nothing. Don't worry over it. The tires on our jets at work can vary as much as 8-10 psi a week or more before we get interested in watching them. Our limits are 5% of filled pressure in 24 hours before we get serious. 5% of 210 psig is 10 psig.....

 

[olytdi]

If the wheels are aluminum alloy, the air may be leaking out of the wheel across a sizeable portion of the surface area. These wheels can become porous over time and leak imperceptibly. Also a real possibility is that you have some very slight corrosion at the stem hole. This would be evident with soapy water at the stem slowly creating a whitish foam at the seal with bubbles so small you cannot really tell that their bubbles. It could be very subtle. You have to give it time, position the wheel such that the soapy water stays pooled at the seal of the stem and keep it wet. Look really closely over an hour or two. I've found that the stems leak more frequently than the bead but the bead also is a possibility. Aluminum alloy wheels interestingly become more leaky as they age.

I have one on a 2004 VW doing what you're describing and I found that it was the stem (or at least I have found some subtle foaming at that spot). It's the same problem you're describing and I lose about the same pressure over the same period of time. I've had the valve stem replaced twice with no joy so I'm looking into what sort of sealant, if any, might work. Having to replace wheels over something like this is maddening!

 

[PoorUB]

I would like to add, I keep hearing about porous aluminum rims, but I have yet to see anyone substantiate this claim.
For a slow leak, if there isn't a hole in the tire, about 99% of the time it is a bead leak.

 

[CJM8515]

1. remove tire
2. drill and wire wheel or similar entire bead
3. mount tire but do not seat bead
4. bead sealer
5. seat bead, leave at max psi for like 30 mins

no more leaks.

 

[TonyG109]

Slow leaks like you are describing can, obviously, be very hard to pinpoint. Like Snyder said, if a soapy solution is used, the leak may only foam, not bubble. This foaming may take a while to become apparent. If the wheel is submerged in water, a leak that slow will give off bubble so small you may have difficulty even seeing them and they will rise to the surface very, very slowly. Patience is required. A good light source like a flashlight may help to highlight the bubbles. Soapy water, as opposed to plain water, may help the bubbles to collect on the surface to make them easier to spot.

Also, if the rim is steel it may have pinhole rust spots. I had this happen and the leak would seep air into the rust scale and not immediately show up when a soapy solution was applied.

In any event, work slowly and use reading glasses if you need them like me! Good luck!

 

[unslow1]

I put some of the slime / goop / tire stuff in the tire. I seem to recall several years ago, someone put 5 or 6 oz of dish detergent in their tires for leaks.

That works well on drag slicks so it probably would on a regular tire but I've never tried it. We use Palmolive.

 

[metlmunchr]

I would like to add, I keep hearing about porous aluminum rims, but I have yet to see anyone substantiate this claim.
For a slow leak, if there isn't a hole in the tire, about 99% of the time it is a bead leak.

I'd agree with this. While porosity was fairly common in old sand cast wheels to the point where many of them had to be run with tubes, that's not the case with the permanent mold castings used today. Not impossible, but extremely rare.

 

[welder4956]

I would like to add, I keep hearing about porous aluminum rims, but I have yet to see anyone substantiate this claim.
For a slow leak, if there isn't a hole in the tire, about 99% of the time it is a bead leak.

Surface pitting is more likely. Porous wheel is not likely. Porosity in a casting usually is a bubble and doesn't provide a leak path.

 

[PoorUB]

My sister in law called me one day, which is unusual as she never calls me. She was complaining that none of her car tires held air and she had taken it to a tire shop and they wanted to sell her new rims and tires, and had never taken them off the car. Her tires were in good condition. Porous aluminum rims they claimed. I told her to take it somewhere else and ask them to demount the tires, clean the rim and tire bead ares and remount. She had it done and no more leaks. I got a thank you call over that one!

 

[KEH]

Put a tube in it? Probably too expensive to be cost effective. The comments about leaking aluminum rims are interesting and informative. I've never had aluminum rims long enough for a problem to become obvious.

KEH

 

[rustyzman]

Spray the whole rim with soapy water just in case it is in the wheel. If not...
Drop the pressure to 10lbs and spray the bead. You may just have a rim leak at the bead. If you do, this usually brings it to light as the bead loses a lot of sealing pressure that low. Give it a try. I found and fixed hundreds of leaks this way (seriously).

Those tire barcode stickers are notorious too. Some come right off and some are almost vulcanized on. Any mount of a new or repaired tire gets bead sealer, without question.

 

[Snip's]

My wife's 2017 Ford Explorer had an extremely slow leak 1-2 psi / week...
Turned out it was some corrosion around the valve stem on the aluminum wheel...
Discount tire warranty covered it. They removed the valve stem and cleaned the corrosion off and replaced the valve stem..
Salty winter roads in Ohio...
Fixed for now at any rate....

 

[DennisK59]

fill the tire to max cold pres. when cold, drive enough to warm tires, about 15-20 minx. at road speeds. raise vehicle and spray with really soapy water solution, when that flashes and off, spray again, Repeat.
Found a wire staple strand that took awhile.