I have a 93 F150 with a 4.9L straight 6 and I currently had to get a new water pump. Well I like to get my hands dirty so I do things myself. Got to the water pump after finding the right fan clutch wrench and now I am having problems with the gasket sealing completely. There is a very small portion of water seeping out between the pump and block. I have tried several different methods of sealing with RTV and new gaskets every time, making sure I have it cleaned off and dry every time. But it still leaks.

any thoughts?

 

I'm guessing it's a bad casting on the pump housing. Take a 12" hard scale froma combination square and run it along the mating edge of the pump, looking for irregularities in the casting. If you find that one area is not right, take it back to the store and get another.

Also, make sure that you have all gasket material removed from the engine.

 

^ What he said.

You don't need a combination square per say, just a good straight edge that you know is true.

If you don't find any irregularities in the mating surface of the pump, check the block. If that's good, here's what I'd do-

First, make sure the gasket surfaces are extremely clean. Take a drill powered wire brush to them if you have to- just make sure every last bit of old gasket material is cleaned off. Then, using emery cloth or sandpaper of a similar grit, lightly rough up the mating surfaces, then wipe clean. This will provide a rigid surface for sealant to adhere to.

Apply about 1/8" bead of sealant to the block. Then apply the same bead to your water pump and give them both about half an hour to set. Then, being extremely careful not to mess up the sealant, install the water pump with the gasket[s] in between the two beads of sealant.

SNUG, do not tighten, the water pump mounting bolts into place.

Walk away, go to the bar for the night, and enjoy yourself.

The next morning, take two aspirin for your hangover [if you have that problem], go back out to your truck and torque the bolts down properly, and reassemble everything.

Allowing the sealant to set up overnight should provide a very good seal. It may also be a good idea to apply a small amount of sealant inside the bores for the bolts before torquing them down as well to prevent possible leaking from the bolts holes.

Good luck- let us know how it turns out.

And by the way... are you the Ron White? And if so, do you own the Sears tower yet? And if so, when can I come over and party?

 

Did you coat the gasket with rtv on both sides?

 

Thanks. and no I am not the real tater salad, he stole my fame

@Nealcrenshaw- I did but it had still been leaking through.

gone to Napa and was told the pump is fine I just have to apply 1/8" of RTV to the water pump/gasket side and press down the gasket to make sure it gets covered and then set the water pump in place and place on

 

NAPA will tell you a pretzel shaped surface was just fine. LOL

Hope it works out for you.