Here's the story-

Back in November I was having a problem with the driver front tire losing air pressure every 2 days or so (the sensor would go off and I would refill the tire and reset the sensor). I took the car to a tire shop and they inspected it and found no foreign objects had punctured the tread. They then took the wheel off of the tire and submerged it in a tub of water and they could not see any air bubbles. Third thing they tried was taking the tire off of the wheel and physically inspecting the inside of the tire. Again it passed.

They put a new valve stem on the tire and said it was a shot in the dark and it may or may not work, then sent me on my way. Up until this past weekend everything was fine, then Sunday the sensor went off again. After checking all the tires it was the same tire I was having the problem with before. I filled it up. Then it tripped again yesterday morning so I filled it on my lunch hour around 2 PM. On the way to work today it went off AGAIN, meaning it lost 20 lbs of pressure in about 18 hours.

So what the heck is the problem? The new valve stem seemingly fixed it (for 2 months)... I'm so confused. I'm going to take it somewhere tomorrow, but can any of you think of anything I should have them try? The only other thing I can think of is maybe a bead on the wheel's seal is faulty? Is that something a shop can check and repair?

 

I had this on a snow tire put on GPMINI a couple weeks ago.
Turns out it had a little rough molding on the outside edge of the tire that touches the inside edge of the wheel - beading?
MoP I think sanded it, then used some sealing goop to be sure - no issue since.

 

Yeah, they should be able to detect a leak of that magnitude in the water bath... may take some time though.

did the tire shop clean the rim up with sand paper? did they use the rubber sealer. It is a tar like substance to help seal the rim, also around the valve stem.

J

 

I would have them try the immersion test again, before they do anything else to the wheel or tire. The air has to be going somewhere. Just make sure that the tub that it is immersed in is deep enough to have the water all the way up the wheel covering all of the tire and valve stem.

It is possible there is a problem with the bead of the tire. I seriously doubt there is anything wrong with the wheel.

 

I think I'll take it to another shop rather than back to the original one. Maybe I'll have better luck somewhere else? I'm completely stumped.

 

Is your car parked outside? I had the same problem with a car of ours that was parked outside. Random low tire. Did the same thing you did, new valve stems, checked for leaks, and nothing was found. Was getting to be a real pain. Then I came up with an idea. I put tape on the valve stem caps. And lo and behold the next morning after the local kids had caught the bus, one of the tires was low and the tape had been messed up. Found out some of the kids had a running dare to let out the air in cars as they walked by. Never enough time to let it all out, just enough to start pi$$ing me off.........LOL

 

but it can be the wheel itself. There can be pin-holes in the casting. I actually have a rim (from another car, rim made in the 60s) that has this casting flaw. You can seal it....

I'd bet its the seal around the rim or the stem. Watch out for sand paper, as the wheel is painted. Also watch out for overly aggresive sealants when the tire is mounted. You don't want to glue it on!

Matt

 

Funny that someone at the first shop suggested that this could be the culprit (vandals or kids whatever), but I keep my car garaged at night and it is usually on the way to work that the sensor goes off. So tampering is impossible.

Also, how safe is it to drive on a "flat" runflat? I plan on filling it up again at lunch but still...

 

The fact that the last shop replaced the valve stem and it was fine for 2 months is intrigueing...

 

You can check the tire yourself if you like for bead leaks. Just take the tire off the car and lay it flat. Fill the space where the tire and rim meet with soapy water and sit there and watch. If there is a leak you should see some bubbles.

If you cannot find a leak in the bead area, check the valve stem in the same manner (put soapy water around it).

I have had tires through the years that leaked and had problems finding the cause. Eventually I found small holes in the tread area caused by a brad or a staple. Very slow leaks, and if the tire stops on the right spot, no leaks at all.

I also thought about the possibility that someone was letting air out as a prank.

Good luck on finding the cause!

 

I had this problem on my old s-lights and runflats, turns out it was some curosion on the rim's inner bead area. They smoothed it out and put some sealent. It was fine, even after i got new tires.

 

Well I'm buying a new tire, having it put on tomorrow morning. The fact that putting the valve stem on it 2 months ago seemed to "solve" the problem last time leads me to believe there's something up with the tire and not the wheel. Instead of wasting 5 hours of a shop's time while they try to find the mysterious leak I'm just going to drop $200 on a new run flat.

Bleh.

 

I have the same problem. Been leaking for 4 months now.
Tire shop tried to fix it 3 times. Pressure goes down like every 3 days.
I'm learning these minis have a mind of their own. Little buggers.

If you do a search on this topic you will find its not uncommon.
I am planning on dumping the run flats and never looking back.

 

how many clicks on the tire??? have the dealer inspect? maybe get a free one for a manufacturing defect??

 

I bought the mini used in August with 40k miles on it. I'm assuming the tires were original, so if that's true then they've had a decent amount of miles on them. The tread is still pretty decent on this particular tire...

I plan on buying aftermarket wheels and tires, but not for probably another year or so. So for now buying one run flat is probably my best bet.

 

http://www.popularmechanics.com/auto...o/4208682.html

 

Well depending on how aggressively you drive, and the difference in tread from the one to the other 3 are, could change your handling a good deal.

maybe try to find a used one from a member that upgraded.. then you could change 2, for prolly the same price.

J

 

i think you need to have load on the tire to find that leak. might take a
while but, i would spray some soap water on the wheel 1/8 of an area
at a time and see if it bubbles. then turn the tire, spray and watch.

inside and outside sidewalls.

 

I have this issue right now. It sucks. I had the tire checked for leaks 2 months ago and they said that brake dust was getting between the tire and the wheel killing the seal. So, they cleaned that wheel, rotated all the wheels and it was fine.

Two months down the road, a different tire is having the same issue. Both times this has happened, it has been with different tires, but always in the front, where there is a lot of brake dust.

No matter how much brake dust I have, the seal should not be compromised, but I truly think that this is the issue. I am taking tire #2 (now loosing air every 3 days) to the tire shop to look for leaks. I will post an update....

 

Ok, so tonight I was driving, maybe 3 miles, and as soon as I got home, I turned the car off and got out of the door only to hear sound leaking from somewhere out of the front left tire, and then a second later, the leaking sound stopped. I tried pushing on the sideway to see if I could make it leak, nothing....

I am so confused.

 

I bought the exact tire as the other 3, so tread should be the same. I had the tire put on Saturday and so far so good =O

 

ding ding ding! this is key. I had an almost identical issue with some Michelin Pilot A/S mounted on BBS wheels for my Subaru. Within a week after the tires going on with new valvestems, one was losing 2psi a day. Turns out the dealer didn't clean the rim seat before putting the new tires on and I was losing air when driving. Nothing showed up on the soapy water test. Cleaning the tire and wheel fixed the issue (took it to an independent shop this time).

 

Ok I have been dealing with this exact same issue since the first of December. I got my MINI in September, and had ZERO issues from September 21 until about December 3. The front driver side tire began to leak after I took a short road trip of about 300 miles, then didn't drive the car at all for about a week. It just happened all of a sudden, I left the driveway one morning and got about 2.5 miles and the tire warning light came on. The temperature at the time was about 38-40 F (This will become an important fact). In that 2.5 miles I went from no problems to ZERO tire pressure. I thought at the time I had picked up a nail, and stopped at a gas station and filled the air. It held pressure for about 8 hours, but on the way home the pressure dropped about 10 pounds (again... temps in the upper 30's)

The next day I stopped by my local tire place, had them look for a nail. Nothing could be found. I had them remount the tire, new valve stem, and balance. I drove home, and everything seemed fine (the daytime temperature at this point was in the low 60s). The next morning I made it about half way to work (15 miles) before the warning light came on again. Once again I lost about 10 pounds pressure and the temperature was in the upper 30's.

This has been going on since... I have found that the temperature outside has a direct correlation to when and how much pressure I lose. I say this because we had a few stretches of about a week where the lows were in the 50's and highs in the mid 70's.... During these unusually warm temps I had ZERO problems with tire pressure. Once the temps returned to the 30's-40's I began experiencing the loss of pressure. I can now drive 15-30 miles at 35 degrees before the tire will lose 10-15 pounds. Also distance traveled may have some bearing on exactly when pressure drops (it seems to drop suddenly, although our warning indicators may react slowly to 10-12 pound drops that could be the amount of rpm loss that sets the indicator off)... this could be due to the abient temp of the tire heating up from rotation and "something" happening like weight shift in a curve that puts more pressure on it resulting in loss.

I have checked for corrosion/brake dust/dirt/pesky kids etc.... and have come to the conclusion that my MINI just doesn't like to be driven in the cold and wants a new pair of shoes... So that's what he is going to get as soon as I pick out a new set of rims & non runflats. at least then I will have at least 3 good runflats with lots of tread to use as spares.


I'm just as baffled as you, but you definately arent alone

Peace,
Scott

 

I had the same problem....random air loss with runflats. I had valve stems replaced, tires dismounted and remounted, soapy water test and could not find the cause. Three tire dealers and my Mini dealer claimed that it was an issue with my ASA wheels. I finally ditch the runflats for conventional tires and the problem went away. Obviously it wasn't a wheel issue.

 

Well so far so good. Three full days after the tire swap and no tire light yet... fingers crossed!