No this is not good. The impeller should not loose any blades. Any lost
material needs to be found as it will clog up the cooling
A very short impeller life suggests it is running dry, not priming properly, the raw water pump
has a rough or worn surface, the impeller is the wrong type, the cooling
water inlet is not always below the surface, there is a blockage in the exhaust elbow
etc. You need to find the cause.