Al E

Will Chrome Valve Stem Covers interfer with the reading of the MB Tire Pressure Sensors?


Thanks,

Al E


Happy Motoring

DFW01E55

They say that chrome wheels can cause problems but I'm haven't heard that just valve stems covers will do it.

cyclrder

the dealer told me that they would... if your car has TPS with actual lbs readings in the dash... the car is equipped with sensors that are actually a part of the stem.. if your car simply has a warning light..then it uses the computer measuring wheel RPM to determine if you have low pressure.

also.. the TPS wheels come with plastic caps (my original wheels with sensors came like this and I had changed them to nice metal ones till the dealer took them off and put them nicely in a little plastic bag on my seat ...during a service).. and non TPS come with the nice metal ones (like the CLS wheels that I got off Ebay).

hope my 2 cents help.

whoover

The parts guy at the dealer wouldn't sell me the AMG valve stem caps because he says TPMS requires I keep the plastic ones. I didn't tell him I replaced them day one with chrome hex head caps that look better with the multi-piece stock wheels. My TPMS seems to work fine with the chrome caps, but I've never heard an explanation of why metal caps are theoretically a problem. The factory clearly says they're a no-no.

whoover

Did a search (it's been nagging at me for some time anyway) -- the reason you're supposed to use plastic is that the TPMS stem threads aren't brass like the ones ordinary rubber valves have. The thread alloy and a steel cap can trigger bimetallic corrosion, causing the cap to seize on the threads.

I haven't seen any hint of it so far, but will keep my eyes open for it. I imagine it's more a problem in nastier climes than California. Just another reason not to drive where they salt roads. But it's good to know it has nothing to do with the functioning of the TPMS itself.

Saprissa

really good info !

Thanks !

Carlos

Saprissa@aol.com
___________________________
1979 230 G-Wagen
2003 C320 Sports Coupé
2004 A210 EVO AMG
2004.5 C320 Sports Sedan
2005 ML350 Special Edition

DFW01E55

Good detective work, whoover.

Heds

I read that the valve stem is made of alloy in your detective work, whoover, but I have also come across somewhere that mention TPMS valve stems are made of aluminum.

So, thought I ask here and find out what most TPMS tire valve stem are made of in terms of material - wouldn't matching the material of the valve cap with the valve stem resolve any potential corrosion problem?

Thks...