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Despite getting brand new tires, back right tire continues to deflate

Hello all. So for reference car is a 2007 Mazda 3 sedan. The car had been dealing with constant deflating of the back right tire back home in NYC. Air would be placed and within a week or so the tire light would pop back up. We brought it to several places where they would place the tire in water and then do some patching of some sort, but the problem would always come back.

Fast forward to now, my GF and I decided that we wanted to move to California and road trip it over there with the Mazda. After seeing a mechanic we changed all 4 tires, all 4 rims, brakes, and rotors. We did make it across to CA, but the tire light STILL popped up about 3 times in a 7 day span to get here.

We had a tire gauge checker, and it normally goes down to about 25psi. Fill it back up to 32 as per recommendations, and rinse, recycle, and repeat.

What could be causing this issue? And how could it be fixed? It’s getting tedious finding 1.50 in quarters several times in a week to fill up the air of that same back right tire.

Thanks everyone.

Has the tire pressure sensor valve core been replaced?



When you got the new tires and wheels,

Did they put rebuild kits (new valve stems) on the TPMS sensors, or just transfer them over ?


Tires need to be inflated while cold. If you inflate while they’re warm they will be approximately 5 lbs lower when they cool. If you inflate and check properly and you have to add air every week, there is a loss of pressure. Many tire places don’t take the time to check for small leakage when testing. Remove tire and with a spray bottle filled with water and some dish soap, spray tire thoroughly. Don’t forget where tire meets rim and tire stem. You should see moving bubbles where air is getting out. If you don’t, go in the house for 10 minutes and look again. Dry off leaking area and mark it with a paint marker. Then bring your findings to whoever changed your tires and rims.

That might be difficult since they moved to California after buying tires and wheels .
It seems it only the back right tire causing problems so the tire monitor and/ or stem may need replacing .

When doing the soapy water test take the wheel off so you can spray every where on the wheel/tire including the inside of the rim…Ive had aluminum rims that have developed a hairline crack that would cause a very slow leak.
Edit: Whoops didnt catch the all new rims part.

Unusual for the new tire on the new rim to leak just like the previous tire on the previous rim did - and at the same location on the car! Are you quite sure the rims are new?

In any case the leak needs to be found. It could be the tire, or the rim, or the place where the tire contacts the rim. Once found, the remedy is not complicated, but could be costly if it’s a defective rim and you’re a continent away from the seller. Good luck and please keep us informed.

Thanks everyone for their replies. Spoke to my mechanic back home with the info you guys gave me, and he said that I should have the valve stem, aka the “insect” changed.

I’ll go get that done in the coming days and report back.

Thanks everyone once again for their help.

The insert. The actual Schroeder valve - it’s inside the black rubber stem which is the thing you see that has a cap on it. It screws into and can be unscrewed from the valve stem. It might just need to be tightened. Any bicycle shop or car place has the tool and has spare valves on hand.

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A good tire shop will usually wire brush the rims when mounting.
You might check if they did. Often corrosion will cause a leak.

I doubt that new rims are corroded.

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When you have the tires rotated does the tire, that was fine, now deflate.
Does the one that had been in the right rear now hold air.

Have you checked the valve’s internal seal by removing the cap and forming a film of soapy water (or spit) over it to see if it expands? If it’s leaking here try tightening the insert, cleaning, or replacing it. A temporary fix is to mount a metal valve cap that has a rubber gasket. If you run without valve caps dirt can get between the valve insert and its seat causing a leak. Sometimes releasing a burst of air will clear this.

It’s uncommon, but aluminum castings occasionally contain porosity that can cause leaks (have encountered this with industrial vacuum systems). It would take quite a bit to cause your problem, unless the wheels are cheap aftermarket…

Based on many internet discussions, many shops do not do a good job of trying to find leaks. They’re good with large, obvious leaks, but leaks that take a couple of days to deflate a tire aren’t given enough time and effort.

So my suggestion is to do it yourself. A kiddie pool or a bathtub can be used, but patience is a virtue. And don’t forget to wiggle the valve. Leaks there aren’t obvious.

The way I read the OP both the old tire/rim and the new tire/new rim would deflate ONLY in the right rear position. That is why I asked about rotating the tires to clarify the problem. Of course the “changed all four tires, all four rims”. Means all eight items are NEW. If the right rear tire/shell holds air in another position, then what?

I hope Selena posts back with the results.

So this morning I went and brought the Mazda in to a mechanic. Told him I needed an oil change after driving cross country, and to replace the valve stem in the rear right. He said he’d do the synthetic oil job, and that he didn’t have new valve stems, but he did have a clean one which he’d place free of charge.

Once the job was done, I drove off. Tire light was still on, but I figured it would only for a minute, which it wasn’t. Light stayed on, so I checked the PSIs and they were all roughly 34-35 after adjustment from the mechanic.

Drove about 5+ hours today. Every time I turned the car back on, the tire light would initially flash before ultimately staying on. Called the mechanic and he said it could be the TPMs is going bad and just a nuisance at this point. He said I shouldn’t worry as long as my PSIs stay consistent.

What to make of this? Damn light drives me crazy. Atleast before it would signal me correctly when the rear right tire was losing air. Now it’s just gonna remain permanently on, and I’ll have a difficult time knowing if there’s legitimately an issue.

Thanks in advance

Those valves have sensors that have batteries and they don’t last forever. The one he gave you probably has a bad battery but the valve itself is OK. So you need a new sensor/valve. Any good tire store will have them for about $85. That’s why they aren’t replaced until they go bad.

Stop going to mechanic shops for this . If you really want it fixed then you need a tire store . Also I don’t see if you replaced the tire pressure monitors when you bought new wheels and tires . They only last 7 to 10 years most of the time.

Tech came to our business yesterday to replace the stolen wheels. The “new” wheels are used but the tires are new. I did inspect the valve stems and they appear new. But are black. I don’t know if a 2015 GM tpms sensor stem is plastic? They took suv back to shop to inspect rotors/suspension.

So I haven’t had the chance to take the car to the tire shop, but in the past 2 days the PSI has dropped from 35 to 28, so the issue persists. The mechanic says he placed an older, cleaner valve stem. So now I have a tire light that’s staying on, and a tire that’s still leaking.

What’s the solution here? I’m going to bring the car back to a tire shop. If I ask for a new TPMS sensor/valve stem combo, that won’t necessarily correct this issue, will it?

All advice is appreciated. Thanks everyone.