water leaking from wear plate? 351w merc

[fstarocka]

Hi there, ive been trying to assess a leaking water pump and pulled it today.. it appears the leak is coming form between the sandwich steel wear plate and pump.

I check both surface with a straight edge and they seem fine.. I assumed my pump seal had gone but then it would have leaked out the front but the pulley as there is no where else it can go -

as you can see there is a visible leak from the bottom part (this side face away from the weep hole and faces the pump body)

here are the pics:

[Diesel Bill]

Looks like the cover gasket failed.

[fstarocka]

odd cos i cleaned it up perfectly and even applied a light coat of permatex ultra since its cast iron and old - gasket was brand new. My wife enjoys making them and we will use felpro stuff thats a little thicker and hold thumbs -

[fstarocka]

im gonna lay a complete bead of permatex ultra on both ends without any gaskets and see if that holds. if not ill try "the right stuff" and go from there!

[bsurvey]

scrape the rust away and fill the low area with JB wed and fair it flat.


worked on my engine head and has been there for over 10 years

[fstarocka]

Yeah that's the issue can't see a low spot.. Have some Permatex ultra and quick drying gasket maker, will lay a thick bead and see how it holds up.. At least temps hold fine if I don't wind it too hard.. So can keep an eye on it..

[Squanderbucks]

I'm afraid you didn't do yourself any favors by using a gasket material thicker than the original. Gasket needs to be thin - a thicker one will just reduce the pumping ability of the impeller. It needs a close seal to the front plate with very little gap between plate and impeller. None if rubber type - slight if metal. Most are paper thin and that is all that is needed and is use as a binder and vehicle for your sealant of choice. The gasket merely keeps you from squeezing out all the sealant and compresses into any pores of the metal mating surfaces.
For self made gaskets - Put a well fitting gasket on your photo scanner and print one out at original size and cut it out with scissors. I use a hole punch like for leather belts for the screw holes. That's what I do for my Jabsco rubber impeller pumps. Aviation Permatex works well as a sealer. Right Stuff Blsck is good too.

[David M]

You can see the low spot by taking a flat file to it. Not to the low spot itself but by brushing the file near the low spot, keeping the file perfectly flat to the surrounding metal.

[fstarocka]

hi guys - thanks for the tips and info. Cleaned all surfaces - I noticed there were 2 holes threaded that had not been used in a long time, very rusted and corroded - RIGHT where the leak sprang.. I bought 2 ss screws and ground the heads flat to get in from the back (between SS plate and block) - there are actually 2 recesses that allow a little bit of room - here is what it looked like before assembling. The gasket is only on the pump-block side, I used permatex gasket maker between impeller body and plate.

Left it overnight so hopefully no more issues. Ill do a reverse flush this weekend and when I do the heads next month will see if theres any rust/crud in the block preventing circulation..

Will keep an eye on the temps and report back - thanks all!

[Kita]

The stuff that's called THE RIGHT STUFF is definitely not the right stuff. I am a very experienced mechanic and one time on a valve cover that I couldn't get a gasket for I used that stuff and then a week later I had to pull the valve cover back off and believe it or not we destroyed that valve cover trying to remove it because of that gasket material. And I've got 30 plus years of working on these things that stuff is kind of like red Loctite if you use it be prepared if you have to remove it again because it doesn't come off easy at all and in this situation is totally unnecessary. You only use that when you absolutely have to and you have no other choice. And that thicker gasket is probably what caused the problem might not have been an issue if you could have went back in there and snug the bolts backup after the engine came to temperature. A thinner gasket you wouldn't have to do that, thicker is definitely not always better