What are the symptoms of a timing chain going bad? I have a 2002 Saturn L300 (3.0 V6).

Hi. As an engine ages, its timing chain stretches. In fact, this is really the main obstacle to long engine life. Some engines will experience piston-to-valve interference if the timing chain or belt skips or breaks. These engines are called non-freewheeling or interference engines. When this happens on a push-rod engine, push-rods will usually bend. Valve timing can become retarded (late) when a timing chain becomes so worn that it skips a tooth, as well. This will cause a slight tap, or valve noise. Late valve timing will cause poor low rpm performance. At higher rpm, engine performance might be acceptable.

If the timing chain has skipped and valve timing is retarded, suction will be felt at the exhaust pipe. This happens because the exhaust valve is still open during the piston's intake stroke. Valve train noises can also come from inside the timing cover. It can be caused by a bad timing chain or a loose sprocket or gear. The noise usually is a rattle or knock that becomes louder when decelerating.

For engines with a timing chain tensioner, a worn chain can become loose enough on the sprocket to rattle whenever the engine floats or cruises between load and coast conditions. In severe cases, a chain can actually wear a hole in the timing cover resulting in an oil leak. Severely worn cam bearings can also be the cause of excessive timing chain slack. Depending on the design of the lubrication system, this problem can also be accompanied by low oil pressure at idle.

Your 3.0 uses a belt, not a chain.....if you have more than 85,000 miles on the belt, it could go any time.....engine destruction is likely.