Poor maintenance can cause the bearings and seals in your Chevy Blazer to fail. A key component of the coolant in your cooling system is a corrosion inhibitor and lubricant that, over time, dissipates during normal evaporation. Servicing the cooling system in your Blazer once a year will prevent premature water pump failure as well as many other cooling system problems. Troubleshooting the cooling system for problems with the water pump is a project that the average weekend mechanic can complete in under an hour. The cooling system pressure tester and mechanic's mirror needed for this project are available at most auto parts stores.
Grasp the cooling fan on your engine, and try to rock it in an up and down direction. If the bearings are worn and movement is present, replace the water pump. This is a common problem with the Chevy water pump and may also be a source of engine noise.
Wait for the engine in your Blazer to cool then remove the radiator cap located on top of the passenger-side radiator tank. Top off the radiator with water and screw the pressure tester onto the radiator cap neck. Pump the tester to 15 psi and observe the gauge on the tester. If the pressure drops rapidly, the leak in the system is severe and should be easy to find with the flashlight. Common sources of leaks include the gaskets between the water pump and the engine.
Position a mechanic's mirror under the water pump, located in the front center of the engine, and shine the flashlight onto it to inspect the small weep hole located on the body of the water pump just behind the fan pulley. This is a seal area that the water pump can leak from. If the weep hole is wet with coolant, replace the water pump.
