Hey guys. I have a 99 3.9 Dakota and have a stubborn coolant leak. I replaced the water pump and gasket and it leaked out of the bottom of the pump, right on top of the balancer. So I replaced it again, and its still leaking from the same spot! I don't know where to look, if there's a step I missed somewhere or something I don't know, just hoping you guys can give me a couple ideas where to start.

 

First thing to do would be rent a coolant system pressure test kit at the parts store, it will help show the source of the leak. Did you replace the bypass hose when you did the water pump? If not it may be leaking too. Be sure to use all new screw type hose clamps. There is a special Permatex sealant for water pumps and thermostats, it works great and sets up quickly. I have found it to be the best sealant for water pumps.

Jimmy

 

It looks like the pump is soft aluminum so if you crank down on the mounting bolts too much you can warp the pump housing.

 

are you getting reman pumps? I've seen them be warped in the box (not one of the checks most rebuilders check for some reason) I had one for a ford that every one on the shelf at 4 different stores (including napa and car quest) were all warped (all used same rebuilder in China) part of the reason I only use new

 

I replaced the bypass hose when I did the plenum gasket a few months ago. And I used the sealer you mentioned when I did it a second time.

I'm gonna pull it apart (again ugh....) and check the pump with a straight edge. Thanks for the ideas guys.

 

I bought my water pump at Auto Zone. I have had it on my truck now for about 3 years, and have had no problems at all with it. It was a new pump, not reman and it was made in the USA too.

Jimmy

 

and probably only a couple bucks more than a reman

 

Yes get new

From service manual

INSTALLATION

(1) Clean gasket mating surfaces.

(2) Using a new gasket, install water pump to engine as follows:

Guide water pump nipple into bypass hose as pump is being installed. Install water pump bolts. Tighten water pump mounting bolts to 40 N·m (30 ft. lbs.) torque.