Fixing a slow leak in a tire?

[BrokenPaw]

One of the rear tires on my car has developed a slow leak.  Over the period of about 5 days, it'll drop from 32psi to about 20psi.  The tire's wide enough (235) and has a low enough profile (45) that there's no noticeable sidewall flattening; I only discovered the leak because the car monitors tire pressure and turns on "Big Idiot Light, With Bing-Bong" if one drops too low.

I've pulled nails out of tires before, and used a patch kit with no problems.  This time, though, I haven't been able to find a nail or anything that would be causing the leak.

Do I need to take it in and pay someone a ridiculous amount of money to find the leak and fix it, or can I use some of that spray-in tire sealant stuff (Fix-a-flat, or something like that)?  I've never used that stuff, so I don't know how good it is.

Thoughts?

Thanks,
-BP

[French G.]

You can use fix a flat if it is damage somewhere in the tread, a leak at the bead or stem doesn't get much out of it. Leak check your valve stem first, just slap some spit on your finger and wipe it across the top of the valve stem to form a film, if it bubbles up there's your problem. After that I'd take the tire off and carefully examine it. Spray bottle of soapy water or dunk the tire in a big container of water to find the leak.

The tubeless plug kits are not ideal but I've used them a bunch too.

[Boomhauer]

"Fix a flat" has never worked for me too well, but we have used this green goop we call "monkey snot". It's available from autozone, and comes in a ordinary plastic squeeze bottle.

We jacked the car up (either front or back, depending on the axle the leaking tire was on- last one was on the back axle), squirted a bunch of that snot in it, and then ran the tire to evenly distribute the stuff. We repeated the process a couple of times to get good, thick coverage.

The tubeless plug kits are not ideal but I've used them a bunch too.

Work just fine for us. We've plugged dozens of tires with them and never had a problem.

[K Frame]

If you have a big tub (or your bath tub) you can over inflate the tire and do your own water test.

I used one of those plug kits earlier this year to take care of a drywall screw that I picked up. It had been in the tire a good long time because the head was largely ground off. It's worked like a charm so far.

[Harold Tuttle]

fix a flat can corrode the interior of a nice aluminum rim

[Desertdog]

Take a liquid dish soap/water solution, or kids bubble solution and brush it around the rim to check for rim leaks.

[41magsnub]

Are they aftermarket tires and do they have warranty?  On my tires any flat repairs are free saving me from having to worry about it.  I do have a can of fix a flat, dinky little air compressor, and a repair kit in both the car and the truck in case I am in the sticks and end up with 2 flat tires.

[brimic]

I went through this a few months ago. My beater truck had a fairly fast leak- fast enough that I couldn't fill it up with the air compressor in the morning and expect to have any air in it at the end of the day.  It happened after I hit a huge pothole on the way home from work. I didn't want to change the tire, because any new repair costing more than $50 was going to be a 1-way trip to the junkyard.

I immersed the wheel in a wheel barrow full of water and found the leak to be on an old tire patch that I put in years ago. I tried tire Slime, but that didn't work.  I tried fix-a-flat and that did work. It hasn't lost significant pressure in several weeks.

[BrokenPaw]

fix a flat can corrode the interior of a nice aluminum rim

Ouch.  Good to know.  I do have nice aluminum rims.  Guess I'll avoid that stuff, then.

I'll do the valve test next.  After that, I guess I'll have to try the soapy-water spray idea to check for tread and rim leaks.

41mag, no, it's the original factory tire, and it has 39k miles on it, so I can't imagine that even if it ever had a warranty on, that it'd still be in force.  This car is a bit odd in that the front and rear tires are different widths and are directional, so they can't be rotated; I've just had to replace the front tires (300 hp V8 and front-wheel-drive combined, and the thing chews through front tires about as fast as you might imagine), but the back ones aren't even halfway to the tread-wear indicators.

I have a paranoid neuron that finds a certain amount of unwarranted coincidence in the fact that the rear tire developed this leak immediately after the car was in the shop getting its front tires replaced.  One wonders if (oops) a wee hole appeared while no one was anywhere nearby, since the car likes that shop so much and wants to go back...

Thanks for the input so far, guys.

-BP

[Sergeant Bob]

It really doesn't cost that much to get a tire repaired at a shop, if you're not comfortable doing it yourself. Likely $10 (at least around these parts) or less.

[280plus]

First I'd get a spray bottle of water and dish detergent and spary the whole tire. Then, if you DO use fix a flat try only 1/4 of a can first, don't put the whole can in, the stuff will settle, harden and then you've got an out of balance tire. Finally, ALWAYS tell the guy who's going to pop the tire off the rim that you have put fix a flat in there so they can make sure to protect their eyes. The stuff WILL spray out of there when the seal is broken and can get them in the eyes. Usually this will make them not happy tire people.

[qdemn7]

It really doesn't cost that much to get a tire repaired at a shop, if you're not comfortable doing it yourself. Likely $10 (at least around these parts) or less.

Agreed, check to see if you have a Discount Tire near you, they fix flats for free, no matter where you bought the tire.

[Lennyjoe]

I've used the tubeless plugs for years. In fact that's in my roadside emergency kit and has saved my bacon on numerous occasions. Plugged a tire on my t-bird and drove that tire for over 40k miles with no leaks.

[BrokenPaw]

I've used the tubeless plugs for years. In fact that's in my roadside emergency kit and has saved my bacon on numerous occasions. Plugged a tire on my t-bird and drove that tire for over 40k miles with no leaks.

Yeah, I've never had a problem with them either; if I knew where the hole was, I'd be all over it with a plug kit.  But spending $10 to get it fixed, versus the amount of time it'd take me to find it and fix it myself, is pretty tempting.  And if what qdemn7 is true, and I can find a Discount Tire near me, it may become a no-brainer.

[mike]

Some places charge extra to fix a tire if you put fix a flat in it. It makes it harder to patch.

[Stevie-Ray]

Ouch.  Good to know.  I do have nice aluminum rims.  Guess I'll avoid that stuff, then.

My guess is either stem or rim leak. Aluminum is notorious for both. Anybody will fix it cheaply. I've never paid more than 10 bucks.

[Tallpine]

If you can find the nail or screw and pull it out, then you will fix the slow leak by turning it into a big one

[Brad Johnson]

Another vote for relegating Fix-A-Flat/Slime to the trash bin.  It goops up the interior of the tire, can cause balance problems, and will likely have your tire shop reminding you not to do it again via an extra charge.

As other have said, immersion in standing water is a good way to check for slow leaks.  Soapy water and a spray bottle work, too, but you need to be patient.  The water will bubble when you spray it.  You have to wait for the bubbles to settle, or to notice new-and-growing bubbles.

Brad

[Manedwolf]

Soap bubble solution can be used too if you don't want to immerse it.

Valve stem is easy fix. Tire face puncture is often fixable. Sidewall puncture, get a new tire.

[Brad Johnson]

Sidewall puncture, get a new tire.

Bah.  That's what tire dope and lag bolts are for, safety be damned! 

Brad

[Nick1911]

Soap bubble solution can be used too if you don't want to immerse it.

Valve stem is easy fix. Tire face puncture is often fixable. Sidewall puncture, get a new tire.

That's a stick, that went right through the sidewall of the literally brand new (I was driving home from the shop) Goodyear tire on my old crown vic.

[Manedwolf]

What did you do, piss off someone with a primitive spear?

[crt360]

The plugs are a decent quick fix, but most will eventually start leaking.  I used to take my auto flats by a repair shop that used the plugs and they always started leaking again.  I finally got tired of taking repaired flats somewhere else to be re-repaired.  I had a little better luck with the plugs on ATV tires (mesquite thorn magnets).

There are a couple of places around here that will remove the tire, check it out, do a proper patch from the inside and have it ready to go quickly for about $12-14.  Unless you have an awesome garage and your time isn't worth much, that's hard to beat.

I buy tires from Discount Tire and have used their free flat fix service several times.  It was free and they did a great job, but they can be very busy - which means you might wait an hour or more.

[thebaldguy]

I hate flats; we just fixed one with a plug last month. I have a home kit, and most places here do plugs. They work pretty good. They are legal in some states, not legal in others. Some states require a patch inside the tire.

As far as your leak, the water tank test is a good idea. Taking it off may make it easier to find the leak or the nail. The valve stem may be bad, or a nick/corrosion/crack on your alloy wheel itself. If you don't have a good jack and stands, compressor, air wrench, and torque wrench (don't overtighten your lugs!) it might be easier to take the car in.

I keep fix a flat in the cars for emergency use only. We'll only use it if we get stuck in a questionable 'hood with a flat. We use it as something when changing a tire is too dangerous.

[230RN]

Withdrawn because my flux capacitor broke down.  Getting a new one from Graingers soon, I hope.  Will be shipped via time machine from 2010, though, so it may take a while.

Re: Fixing a slow leak in a tire?
« Reply #23 on: February 06, 2106, 11:28:15 PM