tire valve stem/core question
It started like this. I bought a C300 new from the dealer with the original everything, except the dealer from whom I bought the car from exchanged nitrogen for air in the tires. So back in Oct 2007 I leased a nitrogen cylinder and have been checking the tire inflation pressure every 2 to 4 weeks. Its gotten to where I'm loosing about a lb of pressure every two weeks which seems to be extreme. By the way, I run my tires at factory recommended pressure as that give me a livable ride. A bit over/under and its too rough a ride for me. Back to the story. This morning I got the bright idea that the dealer must not have put the valve cores in far enough and that they must be leaking pressure. I go off to the local parts house and buy the tool to screw them in and an extra pack of valve cores in case I mess one up. I go ahead and snug all the valve cores in and one went in so far that the inflation thing couldn't reach it, took it out and put in one of the new ones.
Once I got done, I though I'd do a bit more reading. O.K., now I know I should have used a specialized torque wrench to tighten those valve cores and don't have a clue if the valve core I swapped is viable. For that matter, I don't know if the MB dealer that swapped the air for nitrogen bothered to torque them in either.
How do I find out what valve cores I should be using, where to get them (something about nickle plating) and what torque value is appropriate. This is on a 2007 C300 with original equipment tires/rims, etc.
Also, did I do any permanent damage to the TPMS by screwing the valve cores in till they were pretty tight?
See http://buy1.snapon.com/catalog/item....re&dir=catalog







