It seems that for the last 2-3 months I've been getting the Low Tire warning about 1/month. It usually goes away after I pump up my tires with a bicycle pump. Usually it's only one tire that's low, not the same one though.

I have a 2010 MINI Cooper S.
The low tire signal is RED and NOT FLASHING.

What does this all mean?

I have to wait till I go home from work to pump it up. Hopefully that'd be okay. Not sure if the cold weather has anything to do with it, or my tires are leaking.

Thanks.

 

It might mean that you're not checking your tires with a tire pressure gauge frequently enough. If you properly maintain your own tire pressures, your sensors will leave you alone, assuming they're working properly, of course.

Tire pressures decrease as ambient temperature falls, and some air may very gradually seep out over a long period of time regardless of ambient temps. Thus, your tire pressures might currently be set close to the "tipping point" to set off a sensor.

A good tire pressure gauge, a 5-gallon air tank, and frequent tire pressure checks/adjustments will keep the tire sensor monster away.

 

You can also get a compressor that runs off the lighter socket for pretty cheap. I got a Campbell Hausfeld RP0650 - small and light, on/off switch, built in gauge, for ~$15. Beats a bike pump, and you can leave it in the boot. Also, if you don't have one, get a good tire gauge and check at least monthly.

 

I'm showing my age again, but all service stations (now replaced by filling stations) used to have "air stations" and the service station attendant would check your tire pressures along with your oil, brake fluid, and coolant levels. They also pumped your gas and cleaned your windshield while you went in for a root beer. Now the cars monitor themselves and we pump the gas and clean the windshield.

 

It could just be your tire valve core is leaking either due to age or crap stuck on it or cracked.

You can easily get brand new valve cores at the local Wallymart or auto stores, some come with the valve core remover as a kit with four new cores for a couple of bucks.

 

When this started happening to mine, I checked my tire and found that I had a nail. Have you checked to see if you have a puncture? That would be my first thought before a faulty sensor, valve, or otherwise.

 

It shouldn't lose that much air in only a month. Not unless you're underinflating them to begin with. You have a slow leak, simple and easy. If you can't find it, have a shop check it.

You can check yourself by first removing the valve stem cap and smearing some saliva over the entire opening and wait and see if it bubbles outward. I'd put 40+ psi in the tire for this test. Then, if that looks OK, find a tub that you can stand the tire up in and the rim can be under the water. Again fill to 40+ and put the wheel/tire in. Wait a bit and see if bubbles come up somewhere along the side of the tire. Then rotate the tire a bit and keep checking all the way around.

 

You seriously are pumping up and down on a bicycle pump for your car?

Go to Les Schwab or Discount Tire etc and they will fix a leak/flat, often for free. And they will check your tire pressure anytime, free. Have them set your tires 3-5 lbs higher than the door sticker in the winter - I just learned this tech tip myself.

I have to say I learn more about tires and wheels from TireRack.com than any other site! Just yesterday I received the TireRack.com email newsletter about running 3-5 lbs more pressure in the winter in your tires due to lower temperatures. Something I have never considered, and I have been working on and restoring cars since 1973.

 

To the OP: you could also make a soapy solution from dishwashing liquid and pour over the valve stem area, brush or on the rim and tire, etc....this will may show some exterior problem, unless the tire sensor internal is leaking.

 

just pumped it up at the gas station.
Did not use a bicycle pump just used the machine for 75 cents.
It was a fully automatic one. I just set the pressure and the machine pumped and measured it.
all tires except for one was at 38 psi.
My right rear tire was at 29 psi...

Lets see how long this lasts.

 

About as long as the previous time. There's absolutely no point in continuing to wonder if you have a leak or not. It's very obvious you do. Continually pumping it up and then checking isn't going to change that. Get it fixed.

As for using a bicycle pump, I do that myself sometimes as well. It works great on motorcycle tires and on car tires where the internal air volume isn't too high, you can top off your tires with just a few strokes using a good floor pump like a Blackburn. The advantage is that you check your tire pressures cold and don't have to drive to a gas station. Of course, on larger truck tires you can get a bit of a workout.

 

If one is almost 10 lbs off sounds like a leak or a nail to me.

 

If it takes a month to lose about 10 psi.
What kind of leak would cause this?
A nicely embedded nail?

I have Run-Flats. So the dealer will probably tell me to replace it.
I can always have my local tire place look at it. They can patch run-flats, but do not keep any run-flats in stock.

Should I start un-run-flatting my car one tire at a time?

 

Most tire shops and dealers will not fix a run flat because they have no idea how long you drove on it will low pressure. The side wall can fail if it has been driven without the proper pressure for too long. I carry a plug kit and comp. in the boot. I'm not against run flats but I do not have them just becasue I can buy a high perf. summer tire much cheaper in a non run flat.

 

Ok, I had the same problem earlier this year. Could not see anything wrong with the 6 month old tire and needed to add 1 or 2 pounds of air a week..

Brought it in to a tire repair place, and it turned out to be a rim leak. They cleaned things up and added some sort of coating on the inner wheel rim.
$20 and no more problems..

 

iloveminis: I guess that means that it is the same tire that's too low each time. Your initial description that different tires were low threw me.

If it's not from a normal puncture (nail/screw), and not through the valve, it could be from a less than complete rim-tire seal anywhere around the rim, as described by ernesto just above. My last slow leak (about 1 psi every 4 days) was also of that type. They found some roughness (corrosion) on the rim near the valve stem that was preventing a complete seal.

 

NO! No tire shop is going to let you do that. Replace all 4 tires with conventional tires. See my sig for the tires we went with.......

 

Yeah, I was thrown off by that description too, so which is it? The same tire each time or a different one?

If it's the same one, you have a leak - take it to the place that says they can patch it and let them fix it.

And don't trust those auto fill machines, get yourself a good digital gauge from an auto parts store and carry it in the car - then check them at least once a month. I agree with the small compressor idea, they've gotten so cheap it's almost silly not to have one with you, if you don't have a compressor in your garage like many of us do.

 

I swore it was a different tire last time...
Maybe not.

The first time it happened. I ran my car into a curb. The next day I got the low tire warning. The guys at the tire place filled up my tires and said running into the curb probably not the sensor around...

I'm liking the idea of getting a compressor. My car already has 10K miles on it, hopefully the low tire signal will stay out until the 12k mark. That way I'll have the dealer look at it while they change the oil.

 

Definately replace all four if you're going to get rid of the run flats. Or at the very least, replace in pairs, front or rear.

And runflats don't have any more issues leak-wise than non runflats.

 

If the light will go reset the sensor isn't damaged. If it did get knocked around (I think that's what you meant to say) it wouldn't work at all. Most likely you have an object in the tire or you have a pinch hole on the inside of the tire from hitting the curb. When you hit a curb the inside of the tire tends to fold over on itself resulting in a small tear. That lets air escape into the layers of rubber resulting in a goose egg, or it just escapes into the air. It's usually very slow as it has to go through alot of rubber and the tears are usually small. Either way, you should have it looked at and/or replaced. You "can" patch a run flat, it's a tire after all. But, insurance is what keeps places from "wanting" to patch a run flat. You could have driven on it for hundreds of miles with no air in it and compromised the side wall. If it gets repaired and then the tire explodes they will get the blame. The dealership I used to work at wouldn't repair run flats for any reason.

 

Talk about a contradiction - MINI wants us to get 20,000 miles plus on an oil change to save the world - Yet we are to throw away run-flats like they are disposable diapers.....

 

[quote=iloveminis;3199275]I swore it was a different tire last time...
Maybe not.

The first time it happened. I ran my car into a curb. The next day I got the low tire warning. The guys at the tire place filled up my tires and said running into the curb probably not the sensor around...
[quote]

Aha! another piece of the puzzle comes into view......had you mentioned this in your first post you could have saved yourself some reading and time.
You need to replace that tire - now - it's damaged in a way that cannot be repaired.

I've run all my MINIs on regular non runflat tires with no problems for years now - however I haven't hit any curbs with them.

I think you should stay with runflats....

 

It might be ruined, could just need to reset the bead.

 

The tire warning light can come on due to temperature or elevation change. I recently spent a weeks vacation at 8000 ft altitude in cold weather. My tire warning light came on the second day I was there. I normally run my tires at 35 psi, but they were registering over 40 when running warm at the high altitude. I reset the sensor and it was fine. When I returned to warm temps at sea level, I had to reset the sensor again to the new environment.

If you fill & check your tires after you drive home, they are warm. If the weather gets cold over night, that can be enough to get a warning light. If you don't have a slow leak, just check them COLD in the morning, reset, and you should be fine.