Salvaged engines, more commonly known as "junk-yard" engines, are used engines and generally come from vehicles that end up in salvage yards because of collisions or just worn out junks that are sold for scrap. A salvaged engine is risky, at best.

First of all, you can't be sure of the true mileage of a salvaged engine. And there's no way of telling how the engine was maintained or whether it has suffered abusive treatment and/or neglect. Salvaged engine warranties are very rare and exist for a very limited time period. If a salvaged engine fails you're often faced with its cost, plus the cost of the labor to remove the it and install another engine.