* Maintenance: Regular oil changes, proper fluid levels, and timely repairs significantly extend engine life. Neglect leads to premature failure.
* Driving habits: Aggressive driving puts more stress on the engine than gentle driving.
* Operating conditions: Frequent short trips, extreme temperatures, and off-road use can all shorten engine life.
* Specific engine model: Different GMC Jimmy engine types (e.g., V6, V8, different displacements) have different inherent durability. A well-maintained 4.3L V6 might last a long time, while a neglected 5.7L V8 could fail sooner.
Without knowing the *specific* year, model, and engine of the GMC Jimmy, and the maintenance history, it's impossible to give a precise lifespan estimate. However, with proper care, a GMC Jimmy engine could reasonably last 200,000 miles or more, while neglect could lead to failure much sooner.