[Rick Parker]

byroncobra: Use a tapered pipe plug, these are commonly found in the plumbing dept of the hardware store or home suppley depot. The water pump can be threaded without removal from the engine. Put heavy grease on the tap and clean the filings from it as the internal threads are being cut. The few that fall in the pump will not hurt it. Depending on the pump you have, the nipple in question may be a press in or part of the casting. If it is part of the casting, you may be able to thread the interior of the nipple for a plug or it may have to be cut off and dressed first before threading. Some aftermarket pumps actually use nipples that are threaded and can be unscrewed and a plug put in their place.