Lack of oil changes will accelerate timing chain wear a little but not a significant amount. If that were the case all kinds of people would be sitting on the side of the road. (I haven't changed the oil in my '88 Grand Caravan in over ten years and 90,000 miles! That's abuse, not neglect, and I'm in no way suggesting anyone else do that, but it shows what some engines are capable of). Also, when a timing chain breaks or jumps a few teeth, or more commonly a timing belt breaks, you do not replace the entire engine. You repair it. There's two engines available for your car. Both use a chain and neither is listed as an "interference" engine. That means the open valves get hit and bent by the pistons as they coast to a stop. Some mechanics would recommend an entire used engine for that only because they're older, there's so many of them in the salvage yards, that they're cheap. Since yours is not an interference engine you just replace the chain, the sprockets, and any tensioning devices, and you're done. That is not a complicated repair. If your mechanic is not willing to do that, find a different shop.
Also, to identify there's some problem with the timing chain, the mechanic had to disassemble enough to see it. At that point he's part done with the entire repair and he should have seen it through. If he didn't take anything apart he's only guessing. I think you need a second opinion.
Tuesday, March 26th, 2013 AT 9:41 PM