When to replace a Duramax water pump seal?

An overnight shutdown in cool weather should result in the upper radiator hose having little to no residual pressure. If the root cause of a water pump seal leak is due to overpressure, simply replacing the water pump will just buy you a little time.

Is the water pump on my 2001 GMC LB7 Duramax leaking?

The water pump on my 2001 GMC LB7 Duramax had been leaking for some time – we’ll discuss the exact symptoms in a moment. I knew the pump had to be replaced, so I began accumulating the information I needed to do the job correctly. I wanted to know what parts were preferred and which ones should be avoided.

What makes up a Duramax water pump cartridge?

As the lead-in photo and the above photos illustrate, the water pump actually consists of two primary components – the cartridge that includes the impeller and drive gear, and the outer housing that routes coolant both coming and going.

Is the Duramax water pump still corrosion resistant?

From a corrosion standpoint, all wetted surfaces involved with the water pump are as pristine as when they were first assembled more than 16 years ago. This means that Dex-Cool is vastlysuperior to any other coolant used by GM.

When was the original Duramax water pump removed from my truck?

This photo shows the original 2001 model year water pump that was removed from my truck in October 2016. You can clearly see evidence of heat being used on the gear hub and heat-treatment having been applied to the gear teeth. In addition, the photo at the top of the page is a photo I took in March of 2001 at the DMAX engine plant in Moraine, Ohio.

From a corrosion standpoint, all wetted surfaces involved with the water pump are as pristine as when they were first assembled more than 16 years ago. This means that Dex-Cool is vastlysuperior to any other coolant used by GM.

How often should I replace my water pump housing?

The impeller cartridge and the water pump housing are available separately, but most of you shouldn’t need to replace the housing every time the water pump needs to be replaced. The housings can be affected by a process similar to cavitation erosion.

Why is my DEX COOL water pump seal leaking?

Notice how pristine the cast-iron impeller appears here. This is yet more evidence of just how superior Dex-Cool is compared to any other coolant. A leaking water pump seal can be the result of a bad head gasket (or LB7 injector cup seal leak), should compression pressure find its way into the cooling system.