What causes the timing chain of a Nissan altima 3.5SE V6 to start giving a strange sound?

I give my mechanic my car for routine change of oil and the filter and before he gets to the dealership, he's called and tells me the timing chains malfunctioning and i say whats the cause and he doesn't know. I have 193K on mileage. How long can i use it before replacing it cause $2000 is on the high side?What causes the timing chain of a Nissan altima 3.5SE V6 to start giving a strange sound?
Actually the chain guide wears away at the chain tension devices in each head. Nissan Replaces all three chains and two chain tension shoes. I also recommend any worn guides be done while the timing chain cover is off. At your car mileage I would also replace the water pump too. Whirring whining buzzing noise is steel to chain noise don't wait to long. Other high mileage parts think about doing two radiator hoses thermostat and radiator with a new cap any power steering hoses that may be leaking, valve cover gaskets and fan belts too . Motor and power train assembly must be dropped out the bottom to properly perform the timing chain work on a front wheel drive Altima. Make sure your technician has done this job so they will know exactly what to do.What causes the timing chain of a Nissan altima 3.5SE V6 to start giving a strange sound?
Chain has stretched beyond the limit that its tensioner can take up.

OR the tensioner is not working.



No way of knowing how long it will be OK for - could be 1000s of miles and could be 10.

If it breaks or jumps you will need a new engine.What causes the timing chain of a Nissan altima 3.5SE V6 to start giving a strange sound?
why is your mechanic taking your car to the dealership?What causes the timing chain of a Nissan altima 3.5SE V6 to start giving a strange sound?
well said gentlemen!