Water pumps are one of the most commonly replaced parts on vehicles, especially vehicles that are more than eight years old. However, some water pumps may be damaged during the manufacturing process and fail to function properly. In order to avoid spending lengthy hours working on a vehicle’s cooling system after replacing the water pump, you need to know the most common manufacturing errors found in water pumps. These issues may be hidden until you have installed the new water pump, but knowing what to look for can help you in the long run.


Jammed Propeller
On occasion, the casting of a water pump may result in a weld-like connection between the water jacket and the propeller. As a result, the propeller will fail to turn once installed. Before installing, check to ensure that the propeller turns freely. If you are using an electric-based water pump, you can check this through the use of a bucket of water. Pour the water into the receiving side of the water pump. If the water flows freely, then the propeller is working properly. Be aware that very slow flowing streams may be a sign of a jammed propeller. Some water pumps may actually have the propeller visible from the outside, and you can check it by turning the propeller by hand. Also, use this method of checking the propeller for belt-driven pumps.


Failure to Maintain Seal
During manufacturing, the water pump is normally assembled in two phases. Phase one begins with the casting of both the propeller and the pump itself. The propeller is then inserted into the pump, and the pump will be ready to go. However, imperfections in the casting process can damage the seal, which will result in leaks and failure to maintain coolant pressure. The simplest way to check this issue is to cover the exit area of the water pump and fill it with water. Watch for any signs of leaks.

Manufacturers spare no expense ensuring that high-quality products leave their shelves. However, every piece has the potential to be damaged during the manufacturing or shipping processes, and you must be sure the water pump will work properly once installed. By spending 10 minutes checking a new water pump for any manufacturing issues prior to installation, you will avoid wasting time installing a damaged water pump.