My 300TE has 125,000 miles on it and I am unsure if the timing chain has been replaced. I bought it when it had 110,000.


1) How often should the timing chain be replaced?
2) Do the rails and tensioner need to be replaced everytime
the chain is replaced?
3) Is there a way I can check to see if the chain needs to be
replaced aside from taking the vehicle to a mechanic?
4) Is this procedure something I should attempt myself or
should it be left to a professional? If left to a professional,
how much should I expect to pay?