The Impala reappeared in Chevrolet's lineup in 2000, following a brief stint as the Impala SS -- essentially a hopped-up Caprice -- from 1994 through 1996. The 2005 Impala had three available engines -- a 3.4-liter V-6, naturally aspirated 3.8 V-6 and a supercharged 3.8 V-6 -- and all three engines used a timing chain instead of a reinforced rubber timing belt, which has some added benefits and drawbacks.
Benefits and Drawbacks of a Timing Chain
Timing chains have plenty of benefits over belts, but the key benefit is that they are a typically a "lifetime" component. No, that does not mean they last forever, but it does meant that replacement is not part of your Impala's maintenance schedule, so you only need to replace the chain if it breaks. The main drawback to a timing chain is the replacement process when they finally do break. If the chain breaks cleanly and falls without becoming tangled in the sprockets, you can remove and replace it without many problems. If the chain does not break cleanly and catches a sprocket, it can create quite a mess that requires a search-and-removal process to eliminate all of the small pieces of the broken chain.