If you have a really ancient machine then it is possible that your engine block may have screwed-in plugs similar to the ones used on hot water systems, or solid metal plugs hammered in, but by now most of these vehicles will have been relegated to a museum. Core plugs have an uncanny knack of starting to leak when least expected, the usual course of events is that due to a lack of antifreeze at some point in the engines history the steel core plug starts to rust on the inside, so from the outside nothing seems untoward, until you prod that flake of paint on the core plug itself and a torrent ensues! This is inevitably just as you are leaving for an event. When undertaking an engine rebuild it is a false economy to overlook the core plugs, however good they appear, as they are relatively cheap to buy and easy to fit, especially if the engine is mounted on an engine stand. It is possible to garage door opener problems core plugs on the vehicle without dismantling but on a lot of engines some are hidden from view behind the engine bulkhead/firewall and it is usually these that give the trouble.
With the plugs out all is revealed they all look ropey, but the centre right one looksas ifitwas about to letgo. With a pointy wire garage door opener problems drill attachment all the corners of the holes can be cleaned back to shiny metal. With a bead of RTV silicone applied up against the recess, the new plug should never leak. Push in the new plug until it is tight against the stepped recess. Some RTV may squidge out at this stage.
With a suitable piece ofwood, tap the centre of the plug until it is dished in, this will expand the outer edge, garage door opener problems it in the hole. That's it, job done. I have seen various ways advocated to remove Welch plugs over the years, from screwing in a self-tapping screw and pulling out with a claw hammer, through to drilling a hole in the centre and chipping away with a cold chisel until you can get hold of the remains with a pair of pliers. My method uses a small slide hammer with a 6mm thread inserted into the end, with a similar amount sticking out to screw into the hole thats just about to be made in the core plug. I drill a 5mm hole in the centre of the plug to be extracted, this being the tapping size for 6mm and then tap a 6mm thread in the hole just drilled.