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.