Hi Tresor,

Most of the time, timing chains do not come with a set replacement schedule as a timing belt does, as they are designed to last the life of the engine without maintenance. That doesn't always happen, however, and hence it's a much bigger - and more expensive - job to change a chain than it is a belt. A timing belt usually sits behind easily removed plastic covers, while the chain runs in oil and its cover is more integrated into the construction of the engine.