Water pump hose block-off

[mikedevore]

Has anybody tried to seal the bypass & heater holes on a 1970 & up water pump?
I'm wanting to block the bypass off, there are rubber caps for the heater hose connection available.
How about an expansion plug to fit the hole?
Any thoughts?

 

[TrailBeast]

Most people that block them off use threaded plugs.
The problem is threading the water pump housing without splitting it.
The caps are not really up to doing it reliably as they are kind of thin to trust with the heat and pressure as some have found out.

Other than that there is no other apparent issue's caused by blocking them.

 

[krazykuda]

maybe run a loop of hose from one to the other.... (as long as they are the same diameter)...

 

[Kevin D.]

I had mine threaded and run a stainless plug.Although I never had any problem with the rubber caps from Oreillys,Kevin.

 

[mikedevore]

I use the rubber caps also on the heater hose side.
I just keep spares in the tool box & change them every season.
The bypass hole is my biggest concern.
I also have threaded them as well, cracking being the main issue.
Thought I might find an expansion plug & JB welding it into place.

 

[wildbill]

I tapped both of mine with a harbor freight tap (I think I paid about ten bucks for the set) and threaded in pipe plugs. I think the heater hose is 1/4 inch NPT and the bypass hose is 1/2 inch NPT. No leakage or cracking problems so far. One season in my race car.

 

[fishy68]

I've tapped the heater hose nipple successfully but never tried doing the bypass hose. Since it's aluminum you and not real heavy wall you just gotta take it easy when tapping. Aluminum likes to gum up taps so back it out just as soon as it starts getting tight and clear the tap threads and go at it again until you get it deep enough. Before I tapped and installed a pipe plug on the heater hose nipple I tried a set of those rubber hose block off's from NAPA and in less than 10 miles 1 blew out. Never trust them again.