Should it be changed? Not necessarily on a strict mileage or time basis like a timing belt. Instead, focus on these factors:
* Symptoms of a failing chain: Listen for unusual noises from the engine, especially a rattling or clicking sound, particularly at startup. A stretched chain can also lead to poor performance, rough running, or even a misfire. These are clear indicators that the timing chain needs attention.
* Mileage and age: While there's no set mileage recommendation, a vehicle of that age (20+ years) is nearing the point where chain stretch becomes more likely. Higher mileage increases the probability.
* Maintenance history: Has the chain or related components (tensioners, guides) ever been inspected or replaced? A well-maintained engine might have a chain in good condition for a longer period.
* Proactive maintenance: Some mechanics might recommend a preventative replacement around 150,000-200,000 miles or if you're planning to keep the vehicle for many more years. This is largely a cost/benefit analysis. The cost of replacing a chain *before* it fails is significantly less than the cost of the engine damage that can result from a broken chain.
In short: Don't automatically replace the timing chain just because of the vehicle's age. Have a mechanic inspect it during your regular maintenance checks. Listen carefully for unusual engine noises. If you hear anything concerning or experience performance issues, have it checked immediately. The cost of a diagnosis is far less than the potential engine repair costs.
