Just got a 2003 with 170,000 miles and there is a rattling sound from the engine that seems like a timing chain. I took off the drive belt to make sure it wasn't coming from any of the pulleys and it's not. Does this model have problems with the chain after a certain mileage?

 

As a general rule the timing chain should last the life of the engine. That said, I've read instances where the chain has failed in engines which were consistently neglected from an oil perspective (too long in the engine and/or too low of a level). Another cause for a rattle could be valve train adjustment, however, I don't know if the 2003 2.4 liter motor has adjustable valves, so this one is a long shot.

 

What the best way to tell if the chain or tensioner is worn? Pop off the valve cover to check the chain?

 

I've never worked on the 2.4 liter mill in your car, probably best if you do a YouTube search. That said, the general procedure is to pull the timing chain cover and check the slack in the chain.

 

In the shop manual, there's a procedure for checking how much the tensioner spring has extended. It shows the limit where servicing the chain is needed. I don't have that car (or book) any more, but maybe search for that kind of information.