To move the valves in your engine, letting in fuel and air and letting out exhaust, a Jaguar timing belt or Jaguar timing chain is necessary. Actually, to be more precise, the Jaguar timing belt or Jaguar timing chain turns the camshaft, which then opens the valves. But the basic fact remains that if your Jaguar timing belt or Jaguar timing chain is stretched, broken, or otherwise inoperative, your XJ or XK is down for the count. The engine won't run, and if the Jaguar timing belt or Jaguar timing chain happens to break while the vehicle is in motion, major engine damage could result. How major? On some engines, a broken Jaguar timing belt can cause the valves and the pistons to meet at high velocity-never a good situation. What about if the Jaguar timing chain breaks? The same result is theoretically possible, but since a Jaguar timing chain basically never breaks, the danger isn't as significant. The Jaguar timing chain is more likely to experience stretch that leads to poor running over time, as opposed to the Jaguar timing belt which can snap if it's not replaced at the recommended intervals. That brings us to the question of how do you know if you need to replace your Jaguar timing chain or Jaguar timing belt? Check your owner's manual or, in the case of an older Jag, your service manual. There you can find out whether you have a Jaguar timing chain or a Jaguar timing belt, and you can get recommendations on replacement times and symptoms that could indicate failure. And when the time comes, order your premium replacement Jaguar timing belt or Jaguar timing chain from us to save yourself time, money, and hassle.