If the timing chain does break, you will immediately have no power. Timing chains usually last a very long time. Timing belts will break much sooner and must be replaced as per the manufacturer. Timing chains will usually last the life of the vehicle. From your description of the problem, it does not sound like your timing chain broke. These 2.5 liter engines are interference type engines, so if your timing chain did break, you will probably also need a valve job as well. If your timing chain did break, it would be very unusual since timing chains on these cars are almost never a problem.
