Case | Case-IH 521D Radiator & Cooling System. If you are not finding what you need for your Case | Case-IH 521D Contact us here.. You may also want to look in the Belts Category in the previous menu. Most Water Pumps listed are new, but we also offer remanufactured pumps and can even rebuild your core in many cases. Radiator caps and hoses will help complete the repair of your Case | Case-IH.