I have a small block Chevy. The hole to the left below the water pump is leaking. How do I stop that from leaking?

That small opening is a "Weep h0le" for water to escape when a internal seal ruptures, it's to let you know there is a breach. Then you have two options, rebuild the water pump, or replace it. The second option is the less aggivating option, just buy a new pump.

If this is a water pump on your race car, buy a Meziere water pump

Bob

Are you referring to the hole below the water pump mounting bolthole located on the passenger side of the engine?

What hole are you meaning. On a stock style water pump there is a hole in the lower part of the casting. If there is a leak there the seal in the water pump is bad and you rebuild or replace the pump. On a factory 1st gen. block there are more holes on one side where the pump attaches then on the other side. The extra hole is the bypass which is why SBC don't have a bypass hose, it allows water flow when the thermostat is closed. Usually plugged on a race engine.

If you are talking about the hole on the left side of the block below the lower water pump mount bolt hole. Most stock blocks you can drill and tap for 3/8"npt plug. Tap deep enough that the plug is flush with the block.

Are you talking about leaking water or oil if oil from bolt hole next to balancer put short bolt in it if water is probably a bad water pump

quote:

Originally posted by 1leg:
If you are talking about the hole on the left side of the block below the lower water pump mount bolt hole. Most stock blocks you can drill and tap for 3/8"npt plug. Tap deep enough that the plug is flush with the block.

I believe you mean 1/8 npt. No way a 3/8 NPT is going in there.