Water Pump mating surface leak

[40desoto]

Ive had about 4 different used mopar flathead six  engines that I have taken apart and all have had tons silicone goop at the mating surface area.

 

I recently brought my engine home from the rebuild shop and when adding water I noticed a small leak on top of the pump that appeared to come from the mating surface.

I have taken the pump off added sealant to the stud threads and purchased a new Fel-Pro water pump gasket and was wondering if any silicone or other sealing product is recommended.

 

https://www.fme-cat.com/overlays/part-detail.aspx?brandId=FL&pNum=4267&partType=Water Pump Gasket

 

 

 

[Cold Blue]

Don't know if anything is recommended, but I installed a new gasket (Felpro) and smeared a LIGHT coating of Permatex Red High Temp RTV gasket maker on both sides of the gasket. I then installed the pump and just tightened the bolts a little bit. Waited an hour for the RTV to take a set, and then torqued the bolts to spec. I have not have any leaks in a year now...When I got my car it had a huge glob of sealant at the top of the pump too.

[Plymouthy Adams]

only  time you really need sealant is if the mating surfaces are pitted, scratched or not flat and smooth...gasket will by design be enough for a prepared surface.  Have you checked you surfaces with a feeler gauge and flat bar?  Properly applied sealant will not hurt even if your surfaces are prepared....so you call on using it.  

[40desoto]

54 minutes ago, Cold Blue said:

Don't know if anything is recommended, but I installed a new gasket (Felpro) and smeared a LIGHT coating of Permatex Red High Temp RTV gasket maker on both sides of the gasket. I then installed the pump and just tightened the bolts a little bit. Waited an hour for the RTV to take a set, and then torqued the bolts to spec. I have not have any leaks in a year now...When I got my car it had a huge glob of sealant at the top of the pump too.

Thanks for sharing.  Ive always used light sealant and hadnt had a problem.  I was just wondering if it was common for these engines to leak  t the top of the waterpump area.

I will be applying some light sealant as well to avoid any issues.

 

[40desoto]

49 minutes ago, Plymouthy Adams said:

only  time you really need sealant is if the mating surfaces are pitted, scratched or not flat and smooth...gasket will by design be enough for a prepared surface.  Have you checked you surfaces with a feeler gauge and flat bar?  Properly applied sealant will not hurt even if your surfaces are prepared....so you call on using it.  

Thank you Adams.  There not scratched.  Since I have time and engine is on a stand I will be measuring tolerances to see if there is any uneveness.  If there isn't I still plan on using some sealant since it leaked before with a brand new gasket.

 

 

[Don Coatney]

With my fresh engine running on a stand I found a leak below the water pump. It was coming from one of the bolts holding the water pump to the engine block. These bolts penetrate the engine water jacket.

 

Removed the bolt, doped it up, no more leak.

 

 

 

 

[DonaldSmith]

That bolt that anchors the generator-alternator arm has to be loosened to adjust the generator or alternator.  That might compromise its water-tightness. 

I used a stud instead of a bolt, with a lock washer and nut against the water pump.  Then the arm. Then a self-locking nut, not tightened.  (The arm is shown temporarily raised.)

 

 

[Andydodge]

Whilst there maybe the odd bolt or stud that attaches to the engine block and doesn't go thru into a water jacket I'd suggest that would be uncommon.........just about every bolt and stud that I found that goes into the block should have a wipe of some form of sealer on its threads.............this includes the cylinder head, water pump intake and exhaust manifolds.....they all have bolts or studs that go thru into a water jacket somewhere............lol..............andyd 

[40desoto]

46 minutes ago, DonaldSmith said:

That bolt that anchors the generator-alternator arm has to be loosened to adjust the generator or alternator.  That might compromise its water-tightness. 

I used a stud instead of a bolt, with a lock washer and nut against the water pump.  Then the arm. Then a self-locking nut, not tightened.  (The arm is shown temporarily raised.)

 

 

Thank you.  I had the same concern but using a nut in between the pump and my alternator bracket would push the bracket too far forward.  I will be looking for a 1/2 nut to do the job.

 

 

[Sam Buchanan]

How about a bushing in the bracket that is long enough to torque the bolt but leaves the bracket free to rotate....