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TPMS Valve Stem caps with O-Ring

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20K views 10 replies 8 participants last post by  mp06011999 
#1 · (Edited)
Learned something about TPMS today - Our TPMS valve stem caps have an O-Ring inside of them, keeps corrosion causing moisture out. As well keeps the valve stem in place if you tighten them all the way against the O-Ring inside. And you do NOT want to run chrome valve caps because of galvanic corrosion. :eek:

Good article here:

http://www.tirereview.com/Article/59497/selling_safety_tpms_valve_stems_and_service_more_than_just_good_business.aspx

They are extra long and unique to GM valve stems. I have had several correct GM caps missing thanks to sloppy tire dudes at Les Schwab putting the short standard caps on. Between my winter and summer wheel/tire sets I am missing 3 out of 8 long GM caps with O-Rings.

Not to mention I have to educate the tire dude every time, that the sensors in the summer wheels will not magically know they are on the truck now. Every time I have to insist on them using their hand-held gizmo to relearn the tire positions. Beats doing it myself with the release air method anyways.

Anyone know where you can buy the correct GM caps?

:confused:
 
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#4 ·
I work at a tire shop, the cap is really not all that important...
 
#5 · (Edited)
The caps are necessary to keep debris from being set in the valve core. It is possible that the debris could be blown through the valve seat and damage it there by allowing it to leak. Dust caps are absolutely necessary.
Max
 
#6 · (Edited)
I'm betting he meant that the type of material the caps are made from is what's not important.

Word of caution about the TPMS. My 2006 LBZ doesn't have them, but the wife's car does. Her tires were replaced recently due to dry-rot after just 2.5 years. Her car's a 2012. Anyhow, I got into it with the guy at Discount. He insisted that I absolutely had to replace the TPMS stems - have them rebuilt. I told him "I don't think so. They are 2.5 years old and this is the dry desert. No thanks for the up-sale". He actually started to argue with me. I said, "Hey, if they were absolutely necessary then Discount would make them mandatory. No thanks". He was a real arse about it claiming they'll leak in a week.

A quick web search will reveal to you that YES, TPMS stems do need replaced AT SOME POINT usually because the battery dies, but not in 2.5 years. And that tire shops like to replace them everytime NOT because they need it, but because they make money on it and it saves them time letting the air out of the tires. They just cut the stems or break them when they dismount the rim & tire. Sam's club NEVER replaces the TPMS stems here. Go figure.

The Discount guy even said, "The rubber on the tire is dry-rot so what makes you think the stems won't be". Ah, the stems are metal with rubber around them and unless the rubber INSIDE the tire sealing the stems hole through the rim is dry-rot I think we'll be fine. He was a real jerk about it finishing with "well when they leak in a week don't come blaming me".

The SUN light here dry-rots tires fast. It does not shine on the inside of the tire. And with little rain and no snow or salt, corrosion is almost nonexistent in the desert.
 
#7 ·
I should note that the jerk at Discount was just this one guy. The manager that I had been dealing with was great and had zero issues with me not doing the valves. Unfortunately he was on lunch when it was time to write it up. Oh lucky me. lol

Btw, been months and still no issues. Of course.
 
#8 ·
The sensor is independent from the stem.
 
#9 · (Edited)
They tried to sell me on "rebuilding" the stems. Can't recall exactly all what that is, but something about an o-ring and a battery. Either way, my point to them was that the car's a 2012 and there's only been 2.5 years on 'em. "No need". And if they do go out it just means I'll get the reading on the dash saying they need service. He tried to tell me that if I don't pay for the service then they'll leak. A quick google search showed that they like to charge for the service not just because it's an upcharge, but also because they like to rip the stems off or remove the valve to quickly deflate the tire.

Sound "kinda" right? Memory isn't quite what it used to be, but I still wasn't born yesterday. It was when my Sam's Club told me "We never do the valve stem service. We've seen ten year old stems still in great shape. I'd pass" That made my mind up it's not needed.

I did finish with, "I'm more concerned over your guys criss-crossing when they torque down the lug nuts so they don't warp my rotors. Can you please make sure they do that". He wasn't impressed.
 
#10 ·
We never replace the stems when we patch or replace the tires that have TPMS unless there is a problem with the stem itself. With that being said the life of the battery in the sensors seems to be about 5-7 years at which point the new sensor comes with a new stem. Anytime we rotate tires we always reset the sensors to the correct tire position on the vehicle using a handheld device...

I did have a Ram last week that we had to replace 2 sensor stems that were defective and had separated from the brass and looked like little balloons.
 
#11 · (Edited)
Thanks, yea I learned alot about 'em since that post. Just replaced all 4 of those TPMS sensors with new tires. Got to see the throw-away sensors (when battery dead) and the parts (Schrader valve). Funny thing is I recalled this old post the other day doing all this. Didn't recall posting it, just the info. Too funny. Great timing.

I ordered my sensors from DTD on a Black Friday deal (4 for 100). They additionally came with TPMS rebuild packs - valve, nut, washer and cap.
 
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