Hey guys...I have about 470 miles on the car and two weeks ago I came across a LOW TIRE light. I found that the rear passenger's side tire was low (only 22 lbs) while everything else was spot on at 38. I have the OE Conti fun flats on the car. So, I filled the tire up cold to 38 and reset the light. All was good for about 5 or 6 days and then the light came back on. I check that tire and it's down to 30 lbs. Obviously something is going on with the this one tire and/or valve stem/valve core. I took out my valve stem core tool and was able to tighten the core a little bit. I wouldn't say that it was loose but I definitely got a few degrees of turn on it, so....I have done that and re-filled this am and reset the light again.

With this all said, I am going to drive and monitor this tire. I have some valve cores that I got from NAPA but I'll probably stop by BMW/MINI and get some there as well. I'd like to keep the car out of the dealership if possible. If the tire looses pressure again, I will replace the valve stem core and go through the process again. Now...my question comes in in regards to actually taking a socket to the TPMS valve stems. Is this acceptable? I have heard of a few that were actually LOOSE on new cars. I just don't know if I have to have the tire off to do this correctly(to hold backside nut/module) or I can just put a socket on the valve body and slightly torque it? I don't want to turn the module inside as to cause potential issues. Now, I have searched and wasn't able to find anything specifically regarding this....can anybody help? Thanks in advance!

P.S. Tire has already been visually inspected and free of road hazard.

 

It could be the valve stem, but it could be that when the tire was mounted, it did not get a perfect seal...it happens. When this happens, the tire is usually unmounted, the valve/tppm checked, the rim+tire mating/mounting surfaces cleaned, then the tire remounted. Easy, quick, and free/cheap. Just bring it back, have it done...or have it done localy at a convient location for $20 or so. No big deal. Just explain to the dealer what is going on, and it will be done for free....

 

Thanks....I have contacted the salesman and service already but I want to rule these out prior to bringing the wheel/tire down there for them to fix. I figure that nothing GOOD can come out of dismounting and re-mounting the tire except scuffs or scratches. I would also like to rule out some things and do as much as I can on the front end.

 

It could be a porous wheel casting. Or not. Get a bottle of Windex and start spraying and looking for bubbles.

 

DITTO .... crank the pressure up a bit and start spreading around some soapy water to figure out where the leak is and go from there . . .

I've gone so far as to take the wheel off and put it in the swimming pool or bath tub to find a leak (the 10" wheels on the 79 are SO much easier when doing this!)

DO NOT get tempted to just shoot a can of fix-a-flat in .... I did it once and BIG MISTAKE. I learned all the reasons why it is a temp solution only....

 

Put soapy water around the bottom edge of the valve stem and make sure the valve core is tight. If the valve stem is loose, the only way it can be tightened is to have the tire dismounted. You'll need to insert a metal rod from the bottom of the stem (Often comes in a valve stem rebuild kit for TPMS- that tire shops should have these) to prevent it from spinning when you tighten from the other side. I think it's 4 in lbs of torque. Too tight and you'll ruin the aluminum stem. I had one lose air just by having the stem hit a plastic divider on the highway - as soon as I got it fixed, no problems.

 

Thanks for the advice guys. I def would not fill it with fix-a-flat regardless of the situation. I will do the soap and water bit around stem if I continue to lose air. I will keep you posted on what happens. Thanks again!

 

Well...I might have gotten a bit excited. A quick visual inspection this am yielded a nail smack in the middle of my treads. Looks like that is likely the cause for 2.5 or so lbs of air missing per day. While doing this, I was inspecting my other tires and wheels and noticed some fairly deep scoring in my front rotor. Not much luck with this car so far.

 

Good to hear that you found the issue.....
The stock rotors are pretty soft, and the stock pads tend to eat them up pretty fast....BMW/MINI rotors are usually just replaced when new pads are installed...so don't fret....and if you are lucky, the rotors/Pads will be found to be "wearing faster than spec" or something to that effect, and get free brakes/rotors under warranty.
Just enjoy your car....usually when something happens it is the most simple explanation that is the cause of the problem. With the proliferation of the internet, people always want to assume something odd is going on, and sometimes find explanations for things that rarely happen (in comparison to common problems).....just remember, rule out the simple and cheap stuff, and only then move on to the more complex/involved stuff.

 

if you have a nail smack in the middle of the tire

1. DO NOT GO TO THE DEALER for a fix

2. I would not go to any tire place either as you may get the 'runflats can not be repaired' line.... this tire can be plugged

3. Proceed directly to Harbor Freight and ask them to point you to DYNAPLUG and you can fix this yourself for a few dollars.
http://www.dynaplug.com/

4. I keep one (DYNAPLUG) in the Mini and the MINI. I've run a run flat so plugged for another 15,000 miles with no problems.

 

Zippy,
Totally agree and maybe I was guilty of this in this instance and the rotor scoring. I am going to drive it and enjoy it. It's under warranty so...hey, time to motor! Thanks for your perspective and your insight!

Capt bj,
I get a new tire as Continental doesn't patch their run flats. Also, I have the wheel/tire package/warranty so it's "no cost to me" so to speak.

 

Glad you found the problem. I'm well on my way to preparing for the new Continental DWS (on back order). Got a spare, a high volume air compressor, a can of Slime and still deciding whether to buy some lug nuts for the steel wheel.

 

Well...I had the appt today and there was good and bad. They handled it no problem and no charge to me. I brought them a perfectly clean and new wheel and tire to work with and mentioned to please take care. Well, the tech managed to put some fine scratches in the wheel which I buffed out for the most part but still a pain in the ***. Also, the new tire has orange and blue striping on the treads whereas the ones that came delivered had none. So, I now have 3 tires that are black and one that has blue and orange stripes and will wear out at some point I assume.