Water Pump Leaking

[Roy W]

Found an antifreeze puddle under my '05 Duramax today. Appears to be coming from the water pump area. I guess with 150K I've been pushing my luck. Contemplating going to my dealership who has the right tools as opposed to my friendly mechanic. What should I expect to pay for a water pump job ???

[rapidoxidationman]

$700-$900, depending on the dealer's mood and status of boat payments

Do your radiator hoses get soft overnight (good) or is there still pressure in the cooling system in the morning (bad)?

[Roy W]

Dealer wanted $1200........Truck shop is $986. ($728 labor, $120 for water pump, Dexcool $48, distilled water $4., shop supplies $30. sales tax $56.) I went with the truck shop as I had done business with them previously and they do good work.

[More Power]

These water pumps should last for a lot more than 150K miles. While it's possible than a water pump seal just failed (low end of normal life), without any other contributing cause, I've heard of some with hundreds more ks than that without a leak.

Be sure to have the cooling system pressure tested/monitored for a time after the water pump replacement. The coolant surge tank cap has a relief valve that vents pressure at 15-psi. This helps to prevents a cooling system burst that could be more of a problem.

The vent inside the cap can sometimes stick closed, and can hold more than 15-psi. I recommend replacing the surge cap whenever the water pump is replaced. It's not much money compared to a water pump replacement.

Lastly, a normal operational cooling system pressure should be in the 8 to 10-psi range. If your tests result in consistently higher pressures, I'd consider a head gasket problem. If there is a pressure problem in the cooling system, a new water pump won't last long.

[Roy W]

I appreciate the advice MP. I take the blame on the water pump leak, as I never changed the antifreeze in 150K or 10 years, I'm sure the life of the water pump lubricant in the antifreeze was exhausted. I may have only had to add a pint or so of dexcool over the last 10 years. The engine has been a real "puller" and I hope to put another 150K on it before they take my drivers license away. Thanks also for the heads up on the pressure test and new cap.