Break Me Off a Piece of That...Valve Stem

While washing Sarah's 2009 Jeep Patriot yesterday, I had a little meltdown. It was one of those lovely problems that crept up that I wasn't ready for and had never experienced. I was getting ready to wrap things up and wash the rims. They're just the 16 inch steelies, nothing fancy since I like my daily drivers cheap and easy to work on. Imagine my surprise when I rubbed the rag near the valve stem of the rear passenger side tire and I heard a hissing sound and noticed bubbles of soap. A leaky valve? A bad valve stem?

I looked at the valve stem cap and it was crooked, like it had been cross-threaded. So I went to remove & re-seat it. No sooner did I touch it and POW! The cap and the valve stem insert whizzed past my head near my eyes, missing my glasses by millimeters...and shot into the driveway. Having nothing to stop the air from rushing out of the tire, I plugged it with my fingertip, and yelled for Sarah to grab me a valve stem cap from our '76 Chevy pickup in the driveway (thank God for extra vehicles, right?). With barely 2 full threads left protruding from the rim, I was able to cap the tire and move the Jeep to level ground and swap out the tire for the temporary spare (cost cutters).

This is what I saw once I removed the tire.

There's barely enough thread sticking out to cap, and not enough inner threads left for the valve stem insert to thread back in and seal the tire its off to the local Firestone dealer to have them replace the entire tire pressure monitor sensor (TPMS) unit. Yes, you can't just swap out the valve stem in this particular model of sensor, no you have to purchase the whole enchilada at a cost of $25-$55 and then dismount the tire and install the new unit. With labor, we're looking at $85 smackers. This is the cost of being able to see an idiot light read "Tire Pressure Low" on your dashboard.

What a TPMS sensor and valve stem look like.

What's great about this, is that my neighbor came over while I was messing with this and noticed the problem right away since he works at a car dealership. "Oh yeah, the whole stem snapped off? We see that a lot on Chryslers".  He said the cars have aluminum valve stems on the TPMS units, and the newer road salts in the winter are so corrosive that a little bit of it mixed with slush can get under the caps in the winter and corrode the aluminum, especially if you have chrome or metal valve stem caps (like we do). The dissimilar metals literally corrode themselves together and it can eat through the stem until nothing is left.

A call to the Firestone for the appointment yielded the same answer. "We get a lot of Chrysler minivans and cars in our shop with broken or crusty valve stems that leak". Hmm. You see a pattern here? I smell cost-cutting.

Immediately I start thinking...
What if this broke off at highway speed and we lost tire pressure?
What if Sarah was driving and this  happened at night in a dark mall parking lot? 
What if we had been driving with a full load of people and lost control? 

For decades automakers installed brass or stainless steel valve stems for their tires when a car rolled down the line for their corrosion resistance and durability. Then we invented the Tire Pressure Monitor System, so that people would know when a particular tire's pressure was too low or too high. The small sensors made by Siemens and others use radio transmitters that send a signal at 315 MHz to a receiver on the car, which then synchronizes the air pressure readings in all 4 tires and alerts if they're under the recommended range for the car, as determined by the manufacturer. Its billed as a safety device, letting drivers know when a tire could become dangerously low. Everyone loves to be safe.
That means consumers soon EXPECTED that technology in every car and it started costing automakers money to install it. Which means that over time its an area where some bean counter decided to cut costs and use the crappiest sensor, and crappiest materials to make it from. Other manufacturers have "rebuildable" TPMS units, where a valve and seal cost $2-$5 and can easily be replaced while the sensor stays intact. That's a better way to do it. But that's not the Chrysler way.

The end result is a Chrysler recall on the TPMS units (but not for our year, make and model) and a technical service bulletin about them, telling their techs to treat them delicately. Yeah, treat the one thing keeping your tires inflated delicately. You know, the tires you run...on your JEEP...through snow, mud, and rain?

The irony is that all of this cost-cutting came about for a device that consumers and lawyers demanded be installed in our cars & trucks since we can't be bothered to check the tire pressure for ourselves anymore.  



  1. Great blog. Your blog is interesting and so informative. Wait for your next blog post. Thanks for sharing with us. Tyre valves

  2. Just had ours break off while our teen was driving. Thank God it happened right when he pulled into the driveway 2 minutes earlier he was traveling 50 mph and it could have been far worse than the $50 part pluss labor. We have a 2008 Chrysler van bought it in October 2013 with 54,000 miles on it. Engine blew within 2mo and now this. Can not wait till we can get rid of this crap they call a vehicle.

  3. the answer is to put a bit of copper grease on the threads - stops them seizing on too.

  4. I've had something like this happen before. Scared me half to death the the valve shot at me. I wasn't as lucky as you and got hit in the chest by it, and it stung so bad. I was able to fix it but my friend is now having the same problem on his car. I told him to take it to a shop as soon as possible.
    -Seamus |

  5. -Nice blog! Really this was very useful blog for us. Tyre valves

  6. Thank you for this post. My 2010 Jeep Patriot had its left rear valve stem snapped twice in my almost five years of ownership. Each time it happened while in the service station while they were inflating the tire. Really disappointing. To my knowledge there has been no recall on this vehicle. Does anyone know if the newer Jeep Patriot models have addressed this issue?

  7. Filled my 75r16 at one of the new digital air stations and when finished the metal core blew out of the stem.

  8. Same exact thing happen to me today. Same tire too on my 2008 sebring convertible lx .


Post a Comment

Thank you for your feedback on Throwin' Wrenches.

Popular Posts