TPMS Valve Stem Caps - Warning!

If your car has TPMS, and they all do since 2005, don't put aftermarket metal valve caps on the stems!
The stems require silver colored plastic caps, or nickel plated metal caps. If you use chrome plated caps, or metal caps made the old way then you may be in for a big surprise. I had to tow in a car today which the customer put metal replacement caps on two years ago. When he tried to remove the metal cap the valve stem snapped off, the core popped out and the tire deflated before his shocked eyes.
We tried every trick we know to get the other three caps off. We couldn't, they had become one with the valve stem. All four TPM sensors had to be replaced.
What is happening is that road salt is getting between the components and causing corrosion to accelerate. Eventually corrosion eats right thru the stem greatly weakening it.
Although I've read about this problem for a while in the trade mags, this is the first time I have personally encountered it.
So, a special advisory to you snow belt 'Festers; don't use those fancy looking aftermarket metal caps. You could get a rude shock one day when you go to add air to a low tire.

Originally Posted by DSXMachina

If your car has TPMS, and they all do since 2005, don't put aftermarket metal valve caps on the stems!
The stems require silver colored plastic caps, or nickel plated metal caps. If you use chrome plated caps, or metal caps made the old way then you may be in for a big surprise. I had to tow in a car today which the customer put metal replacement caps on two years ago. When he tried to remove the metal cap the valve stem snapped off, the core popped out and the tire deflated before his shocked eyes.
We tried every trick we know to get the other three caps off. We couldn't, they had become one with the valve stem. All four TPM sensors had to be replaced.
What is happening is that road salt is getting between the components and causing corrosion to accelerate. Eventually corrosion eats right thru the stem greatly weakening it.
Although I've read about this problem for a while in the trade mags, this is the first time I have personally encountered it.
So, a special advisory to you snow belt 'Festers; don't use those fancy looking aftermarket metal caps. You could get a rude shock one day when you go to add air to a low tire.

I think the main problem here is that he had obviously not checked the air in his tires in two years. As you are aware I use after market metal valve caps. I coat the threads with on the stems with vaseline before I put the caps on. I also remove them once a month to check tire pressures.

I rarely drive in road salt. I had to take the car out yesterday and when I got home it was dirtier than it has never been. It was washed as soon as I got back to the garage and is now happily sleeping under its cover.

CA

Originally Posted by DSXMachina

If your car has TPMS, and they all do since 2005, don't put aftermarket metal valve caps on the stems!
The stems require silver colored plastic caps, or nickel plated metal caps. If you use chrome plated caps, or metal caps made the old way then you may be in for a big surprise. I had to tow in a car today which the customer put metal replacement caps on two years ago. When he tried to remove the metal cap the valve stem snapped off, the core popped out and the tire deflated before his shocked eyes.
We tried every trick we know to get the other three caps off. We couldn't, they had become one with the valve stem. All four TPM sensors had to be replaced.
What is happening is that road salt is getting between the components and causing corrosion to accelerate. Eventually corrosion eats right thru the stem greatly weakening it.
Although I've read about this problem for a while in the trade mags, this is the first time I have personally encountered it.
So, a special advisory to you snow belt 'Festers; don't use those fancy looking aftermarket metal caps. You could get a rude shock one day when you go to add air to a low tire.

you had to replace the sensors?? or just the stems?

Galvanic Reaction. Years ago I was installing the sprinkler system in a Post Office. When it came time for the punch list corrections, one item on the list was a 1/2" brass nipple in the otherwise galvanized piping for the alarm valve. Shaking my head in disbelief, I approached the inspector (Lieutenant, Army Corp of Engineers, newbie) and asked about it. He says that the brass nipple has to be removed due to possible galvanic reaction. I started laughing and pointed out that EVERY valve (drain valve, inspectors test, check valve..) in the system is brass and oh yeah, what about ALL the sprinkler heads, they are brass, what are we gonna do with them? He agreed and the nipple remained. Bottom line, No Electrolytes (salts), No Corrosion, at least in sprinkler systems.

dj

Originally Posted by Orient330iNYC

you had to replace the sensors?? or just the stems?

Isn't it all one piece?

dj

Originally Posted by djfitter

Isn't it all one piece?

dj

No, they're Beru's as suggested by Orient, above, but I didn't want to go into too much detail. Beru makes a two piece unit and the stem can be purchased separately. Only Beru makes them this way.

Originally Posted by captainaudio

I think the main problem here is that he had obviously not checked the air in his tires in two years. As you are aware I use after market metal valve caps. I coat the threads with on the stems with vaseline before I put the caps on. I also remove them once a month to check tire pressures.

I rarely drive in road salt. I had to take the car out yesterday and when I got home it was dirtier than it has never been. It was washed as soon as I got back to the garage and is now happily sleeping under its cover.

CA

Absolutely right and that's what happens when we come to think that electronic devices are going to save our *sses. Why should he check his pressures, the TPMS will tell him when the system needs attention! Yeah, right.

Captain/DSX,
Please clarify re: "aftermarket valve caps". Are these one and the same as the caps sold under the P/N 36 11 0 009 840 that are available from BMWUSA?

Originally Posted by Nordic_Kat

Captain/DSX,
Please clarify re: "aftermarket valve caps". Are these one and the same as the caps sold under the P/N 36 11 0 009 840 that are available from BMWUSA?

If they are not plastic, and you are worried, do what CA did and Vaseline them. No Worries.
Also presumable you check your tire pressure more often than every 2 years.

dj

Our Acura MDX (and my dad's Honda Rdigeline)--both with TPMS--had a safety recall for this exact issue. The vehicles came with metal caps standard, and Honda just mailed out four replacement gray plastic caps to every registered owner on file, with the instructions to swap them out.

It does not take 2 years for galvanic corrosion to wipe out your valve stems. My MDX valve stems froze to the metal caps in one summer stored in my garage basement. The tire pressure checks you all seem so fond of making your selves are not necessary in the MDX because the TPMS reads out in PSI so you can check your pressure any time (and watch them change as the sun hits the tires on a freeway good for 1-2 PSI depending upon the season). So when I put my tires on in the fall, all 4 stems were frozen, and I don't carry Vaseline or any anti-seize for my schrader valve stem caps so don't even start with that.

Cost the boys at TireRack 4 TPMS, mount and dismount, plus my friendly face in their office for an hour!

BTW, who checks air pressure every month? Do you all have leaky valve stems? Tires hold air, then they go flat, why check them all the time? My BMW tires hold air, all the time, every day, it's weird, but I think tires are supposed to hold air.

Originally Posted by From the Helm

It does not take 2 years for galvanic corrosion to wipe out your valve stems. My MDX valve stems froze to the metal caps in one summer stored in my garage basement. The tire pressure checks you all seem so fond of making your selves are not necessary in the MDX because the TPMS reads out in PSI so you can check your pressure any time (and watch them change as the sun hits the tires on a freeway good for 1-2 PSI depending upon the season). So when I put my tires on in the fall, all 4 stems were frozen, and I don't carry Vaseline or any anti-seize for my schrader valve stem caps so don't even start with that.

Cost the boys at TireRack 4 TPMS, mount and dismount, plus my friendly face in their office for an hour!

BTW, who checks air pressure every month? Do you all have leaky valve stems? Tires hold air, then they go flat, why check them all the time? My BMW tires hold air, all the time, every day, it's weird, but I think tires are supposed to hold air.

So tires have two states, full and flat?

Originally Posted by From the Helm

It does not take 2 years for galvanic corrosion to wipe out your valve stems. My MDX valve stems froze to the metal caps in one summer stored in my garage basement. The tire pressure checks you all seem so fond of making your selves are not necessary in the MDX because the TPMS reads out in PSI so you can check your pressure any time (and watch them change as the sun hits the tires on a freeway good for 1-2 PSI depending upon the season). So when I put my tires on in the fall, all 4 stems were frozen, and I don't carry Vaseline or any anti-seize for my schrader valve stem caps so don't even start with that.

Cost the boys at TireRack 4 TPMS, mount and dismount, plus my friendly face in their office for an hour!

BTW, who checks air pressure every month? Do you all have leaky valve stems? Tires hold air, then they go flat, why check them all the time? My BMW tires hold air, all the time, every day, it's weird, but I think tires are supposed to hold air.

This wasn't the point of the thread, nor was the 2 year time frame. What is the point, you already found out about, and my tire pressure may not change monthly, but how would I know if I didn't check. The TPMS will let it vary (2-3 psi?) by more than I want.

dj

Originally Posted by captainaudio

So tires have two states, full and flat?

Maybe he can tell by looking at them, "well they don't look flat to me" yet.

dj

Originally Posted by djfitter

This wasn't the point of the thread, nor was the 2 year time frame. What is the point, you already found out about, and my tire pressure may not change monthly, but how would I know if I didn't check. The TPMS will let it vary (2-3 psi?) by more than I want.

dj

+1, check them weekly myself, but this has been covered in another thread I'm sure

Originally Posted by djfitter

If they are not plastic, and you are worried, do what CA did and Vaseline them. No Worries.
Also presumable you check your tire pressure more often than every 2 years.

dj

Thanks, DJ, but that wasn't why I was asking. I don't know if the caps I referenced are plastic. I was hoping someone else might know. I was just getting ready to purchase a set of the ones I referred to. I was hoping for a little guidance before I bought something that could be potentially a big problem. Hence, my question.

And yes, I am pretty good about checking my tire pressures on a regular basis.

Originally Posted by Nordic_Kat

Thanks, DJ, but that wasn't why I was asking. I don't know if the caps I referenced are plastic. I was hoping someone else might know. I was just getting ready to purchase a set of the ones I referred to. I was hoping for a little guidance before I bought something that could be potentially a big problem. Hence, my question.

And yes, I am pretty good about checking my tire pressures on a regular basis.

Kat, you may want to give Tischer a call, their parts guy may know right offhand the material used for those, and for the price, I hope they are not plastic but you never know. They are not heavy I wouldn't think.

Originally Posted by From the Helm

It does not take 2 years for galvanic corrosion to wipe out your valve stems. My MDX valve stems froze to the metal caps in one summer stored in my garage basement. The tire pressure checks you all seem so fond of making your selves are not necessary in the MDX because the TPMS reads out in PSI so you can check your pressure any time (and watch them change as the sun hits the tires on a freeway good for 1-2 PSI depending upon the season). So when I put my tires on in the fall, all 4 stems were frozen, and I don't carry Vaseline or any anti-seize for my schrader valve stem caps so don't even start with that.

Cost the boys at TireRack 4 TPMS, mount and dismount, plus my friendly face in their office for an hour!

BTW, who checks air pressure every month? Do you all have leaky valve stems? Tires hold air, then they go flat, why check them all the time? My BMW tires hold air, all the time, every day, it's weird, but I think tires are supposed to hold air.

Here's why some of us check pressure more than others; we know the importance of varying tire pressure for the conditions. My E92 has an acceptable and required pressure range from 32 to 40 (!) psi. Proper inflation pressure varies with speed and load. The proper inflation pressure for my car is 40 if I have four passengers and luggage, or if I will be travelling at very high speeds.

Originally Posted by Nordic_Kat

Thanks, DJ, but that wasn't why I was asking. I don't know if the caps I referenced are plastic. I was hoping someone else might know. I was just getting ready to purchase a set of the ones I referred to. I was hoping for a little guidance before I bought something that could be potentially a big problem. Hence, my question.

And yes, I am pretty good about checking my tire pressures on a regular basis.

Hi Kat. I would hope that any caps purchased from BMW would be coated to minimize potential corrosion. Also, you're not laying down salt in Houston are you? You are near the Gulf and I suppose salt air could blow in with ocean storms...
[Is that the Alps with the Matterhorn in your sig pic? Trying to outdo me?]

Originally Posted by thekurgan

Kat, you may want to give Tischer a call, their parts guy may know right offhand the material used for those, and for the price, I hope they are not plastic but you never know. They are not heavy I wouldn't think.

Kurgan -- Thanks for the great idea -- sounds like either a phone call or a stop at the dealership across the freeway might be in order.

Originally Posted by DSXMachina

Hi Kat. I would hope that any caps purchased from BMW would be coated to minimize potential corrosion. Also, you're not laying down salt in Houston are you? You are near the Gulf and I suppose salt air could blow in with ocean storms...
[Is that the Alps with the Matterhorn in your sig pic? Trying to outdo me?]

Hi DSX -- We don't have to lay salt down or have a big storm to have low grade corrosion, so I'd rather be safe than sorry. Everytime we get a south easterly breeze we pull alot of moisture off the gulf. I would hope the caps are safe as when I do an accessory search using the year/Model search function on the BMWUSA site, it pulls them up.

[Yes -- you guessed my sig pic. Not trying to outdo you, just trying to find something appropriately snowy so as to not get you too frustrated. (lurid )
(Picture was actually 4 panoramics taken with a 35 mm film camera from Gornergratt -I love Photoshop!)]

Originally Posted by Nordic_Kat

snip
Hi DSX -- We don't have to lay salt down or have a big storm to have low grade corrosion, so I'd rather be safe than sorry. Everytime we get a south easterly breeze we pull alot of moisture off the gulf. I would hope the caps are safe as when I do an accessory search using the year/Model search function on the BMWUSA site, it pulls them up.

snip

Does the air from the refineries/ chem plants affect clearcoats or exposed metal?

[This sig pic was taken from my hotel room in Anchorage, at sunset across Turnagain Arm. It was cropped from a larger pic but otherwise it is as taken. I may have pushed the exposure a little to bring up the water though.]

Originally Posted by DSXMachina

Does the air from the refineries/ chem plants affect clearcoats or exposed metal?

/snip

Yes, the refineries/chemical plants definitely have an effect. I'm lucky, being about 45-50 miles away from the Ship Channel, but 'minor' chemical releases at refineries and plants aren't uncommon, and even at ppm levels in the air, things like H2S can eventually eat into finishes. Our Canadian brethren were kind of razzing me about my obsession with waxing etc., but our air quality, combined with the brutal heat in the summer, can over the long haul be every bit as damaging as the salt/sand the northern climates have to endure during the winter months.

'Last time I stopped by the dealer, they were still selling both sets of caps: metal and plastic. They look the same, but the plastic ones, of course, feel much lighter and won't cause a problem.

To get the corrosion you need metals that are rather far apart on the galvanic series (http://en.wikipedia.org/wiki/Galvanic_series) and water. Pure water is a lousy electrolyte. Dissolve a salt in it, and you're good to go. But there are plenty of other impurities that can make water a better conductor and accelerate corrosion. So... even if you're in an area that never salts the roads (lucky you), I'd still be wary about the whole valve cover thing.

And, btw, I had a flat recently. The RFT didn't look flat at all (naturally). Really. How hard is it to check tire pressures?

Now that I am aware of this issue I immediately went down to the garage and removed the fancy metal BMW logo caps and replaced them with the original cheap plastic ones.

The results were instantaneous and spectacular. My migrane headache went away, my acne cleared up, the interest rate on my IRA doubled and I won $500 in the New York State Lottery. This was particularly amazing since I hadn't even purchased a ticket.

CA

Professor Cook,

On another topic (sorry) - where did you get the bra for your car? I've ordered a 328 coupe, and want to put a bra on it at the dealers when it comes in. I have a 30 mile freeway trip home.
Thanks