Core charges are a type of a refundable deposit issued on engines and parts that can be remanufactured and used again in the future. Once you receive your new part/engine, you ship us back your old used part/engine. After we receive your core (the old part/engine), we will evaluate its components and condition. If it meets our criteria, we will issue a full refund. If there are any issues with your core, we will always prorate it and issue whatever partial refund is due. Typically, cores are due back within 30 days of receiving your new part/engine to receive a full refund.