I just got back from my trusted MB dealer where the service tech warned me that my after-market metal valve stem caps were corroding the valve stems and TPMS sensors.

Basically, he said a couple of bucks at Wal-Mart for plastic caps will save me $200 per tire!

The previous owner of my CF put those metal ones on. I had no idea they weren't stock.

It also goes to show me that my MB dealership is looking out for me.

As a side note, MB also changed the oil grade from 0W-40 as well, not just Chrysler.

 

What did they change the oil too?

 

Think mine are aluminum, so those be OK..

 

Discount Tire told me the same thing. Go with plastic no worries.

 

Go with plastic.

The metal (either steel, stainless, or aluminum) will cause a chemical bond with the valve stem over time. Anytime you put dissimilar metals together you can expect a long term reaction, be it chemically "welded" or the opposite, corrosion. These negative effects are magnified by the fact that our valve stems are actually part of an electric sensor.......think electroplating, electrogalvanizing, etc.

 

Here's the deal folks, yes they do corrode at some point but heres what I have done. I simply unscrew them when I wash the car, shot of silicone spray and put em back on. I've never had an issue but I do that regularly. Now that said my daughter took her Audi in for service at the Audi dealer and when the guy tried to remove hers he ripped the stem. They tried to charge her $100+ for a new stem and then told her by the way they all need to be replaced ($400+). NOT SO FAST! You simply heat the metal cap with a lighter or other device. We have a really neat little propane torch. After a few seconds wrap a towel around it so you don't burn your fingers and it will come off. This worked on the other three that had fused/ corroded on her car. Because there is no way she will ever do my fix we replaced hers with plastic caps like Apkano suggests. I've noticed that whenever a tire place fills a tire with Nitrogen they use these fancy little metal caps with a green tip or writing on them. You should check your caps.

 

My son had same problem with his girlfriend,s Honda...Has sensor valve-stems as well..He told me about it so I checked the ones on my xfire and they looked like they were made of aluminum..I took each one off and sprayed with lithium grease..so far no problems...

 

Last week was really cold & snowny in KC, my garage was about 35 F & my pressures were all about 32 psi. I decided to pump the tires up to 36 psi .... cause I was going to work an evening shift & there was a chance it was going to be about -10 F when I got off work. When I took the compressor off the last tire....the little core valve stuck "in".....try as I might I couldn't get it to pop back out.....till I sprayed WD-40 in there.....

 

I have the steel ones on mine. I give them a turn off and on around once a month and haven't had any problems. My car doesn't go out in rain or snow though.

 

Is it by accident or did I noticed that all of you who wrote in were in areas of cold, damp and snowery winters. I agree it is to small a sample but I did notice a trend or don't you check the tire pressure frequently i.e. remove the valve caps.

 

I think the salt on the roads causes the dissimilar metal reaction and corrosion. I put aluminum caps from Wal-Mart on my Durango when I lived in NY. 3 or 4 months later (it was during the winter), I went to check the pressures and couldn't get any of them off. I was able to cut 2 of them off with a Dremel, but messed up the other 2 stems badly enough that I had to have them replaced.

I put metal caps on my Crossfire, but put some anti-sieze compound (get it at AutoZone) on all of the stems before putting them on. Now I turn them off and on every time I wash it and haven't had a problem yet.

 

I live in a cold and damp environment too and I too have metal valve caps. I check my tyre pressures weekly and have never suffered from seized caps.

 

NYPD-Crossfire said,

texas t said,

Me,

What did they (Chrysler/MB) change it to?

 

Union Centre or Montgomery Road?

 

James 1549,

When I see that photo of your car I know why I love the design!

 

Just a reminder - If your caps seize try heating them with a lighter or a torch ( we have a small SnapOn torch for use in tight spaces). I was told my daughter's car would need 4 new stems and sensors. We got the other three off by heating them a bit, no problems. The dealer broke the 4th one. If you are taking your car in for service I'd suggest checking the valve caps before you drop the car off. All you need is a inexperienced tech to get a little heavy handed. By the way, my stock wheels came with metal caps, so did my daughter's Audi.

 

Our green (Nitrogen) caps are plastic.
I also check the air pressure on a regular basis. I do this in the garage when the tires are cool and I've also invested in a small doughnut shaped air compressor to fill them as I check them--phooey to Nitrogen as it is too much trouble for such little/questionable benefit.

 

I agree with you on the Nitrogen. If it was the standard ok but its a PIA otherwise.
Pat