Engine exchange is a term used for replacement of the engine. At some point the engine in a vehicle may wear out or have a mechanical break down that out ways the cost of repairing the engine. Should this happen to you there are some options. 

The term re-manufactured engine means that the engine has been completely rebuilt. Rebuilt means that all the major components have been either replaced or reconditioned. All gaskets and seals have been replaced. These engines carry a warranty of three years unlimited miles. When you replace an engine with a re-manufactured unit you can expect to get many more years of use out of the engine. 

The other option is a used engine. Used engines are extracted from salvaged vehicles. Salvaged vehicles are vehicles that were damaged in an automobile accident. The used engines are tested and the odometer reading is recorded. It is very possible to get an engine with low mileage to replace the worn out or defective engine in your vehicle. An example would be your vehicle has 198,652 miles on it and the engine failed. A used engine has been located with 54,378 mile on it. The used engine is installed in your car and it is running great with much lower miles on it. With proper maintenance you will get several more years of use out of the vehicle. 

Re-manufactured engines are more expensive than the used engines. The warranty on the re-manufactured engine is much longer than that of the used engine. The decision will be up to you.