3.5L engine issues

Hey everyone,

I'm new to the Nissan forum, but I'm pretty active in the Ford forums. I've got a question regarding my brother's 2005 Nissan Quest.

It's got a 3.5L engine and he mentioned that it was ticking in the morning. One day his wife drove over and it wanted me to look at it. (he was out of town). It was completely silent...I couldn't hear it. He mentioned that it did it when it was cold, but then would go away as the engine warmed up.

He came over one day and it was doing it. I grabbed my stethoscope and went to poking around. I could definitely hear it, but was unable to track it down before it went away. After some research and Youtubing, I am almost certain that he has a timing chain issue. It's apparently very common on this engine.

Here's my question. I've read where some people claim that it's just the timing belt tensioner thats worn out. What would be likelihood of just replacing that and not the entire chain? Or is the chain worn out too. I'm not positive on the mileage, but I believe its around 70k. That sounds very premature for a timing chain. I have a 2000 Windstar w/ a timing chain that has almost 200k on it.

Has anyone ever changed out the timing chain. I've done it in other vehicles, but never with one this long. I'd appreciate any tips/advice anyone might offer on the job.

I realize that this is on a Quest, but I believe the engine is used in numerous Nissan models.

Thanks,

Mark