I've changed out 2 pumps now and I'm getting leaks only after I do some hard runs getting to 130+mph or standing on the throttle like 1/4mile WOT. The RPMs get to 3500+. I've had 2 not leak at all after install, then start leaking after these real hard runs. I didn't go back w/ a factory water pump, they were brand new pumps from 2 diff Oreillys; is that my problem? Or is this a serious sign that I need a coolant bypass/pressure relief kit?

 

bump.........

 

im gonna say that it is the oreilly's pump you need to put a cummins oem one on it.

edit: where is the coolant coming out of?

danny

 

It's leaking from the back of the plate. The groove(the gasket rides in) on these water pumps seem to be very deep. I greased the gaskets and cleaned the mounting surfaces really well. Right now it's not leaking at all, but if I haul **** WOT, I can pop the hood and there will be coolant all aroung the water pump. The dealer wants 200+ for the water pump, but if I have a different issue a factory pump won't help!

 

It may be the combination of the aftermarket pump and high coolant pressures.
I recently blew my headgasket after getting the head o-ringed. When I took it back apart The coolant pressure blew apart the fiber on the 12valve marine gasket in the coolant passage by the #6 cylinder and I had coolant coming from between the head and block. I also had the rear freeze plug blocked off.
I now have a coolant bypass system I fabbed up and It hasn't blown yet.
I also blew the gasket running Beta 4.2 w/ TST at the dragstrip and the truck was warm on all runs.

 

The only difference in these aftermarket pumps is the impeller blade has a ring welded to it, I'm not sure why.

 

are you sure it is coming from the water pump and not the radiator cap above the water pump it sounds like it is probably time for a bypass.

danny

 

I'm absolutely positive it's coming from the water pump, are these bypasses reasonably priced? I'm going to try a factory pump tomorrow and if it leaks I'm not sure where it will land when I throw it!