My son owns a 2011 Ford Focus SE 2.0 with 96K miles. As you probably know, it has a timing chain. I believe it is the same engine in a Mazda. One mechanic tells me that it never needs to be replaced, which I doubt. I just watched a video where some mechanic with a very german accent tells me that I must replace it with no more than 100K miles, or count on trashing the engine. He says the chain and sprockets are too thin, and the tensioner spring gets weak causing a host of problems. He also says that all the main bolts must be replaced with new or they will work loose and that most mechanics don't put the correct torque on them. Another mechanic tells me they don't do timing chains on this car because getting the timing right is a nightmare. HELP! What is correct about this car? Sorry for the long message, but you have become the go-to mechanic for the truth.