Can anyone advise how to change water plug located behind starter on engine block of 1988 Chevy Blazer S-10?

Answer 1

Freeze plugs are normally something you change at overhaul time when the block is stripped, it has been through the acid bath, and the core is clean. Changing one on the fly is hard because you often end up with leaks worse than you had before you changed the plug. Since they are a press fit, the mating surfaces have to be in good shape. Changing a rear one is the hardest. Start by buying the new plug and then with a large screwdriver, or chisel, remove the old one. Drive the screwdriver into the middle of the plug and then with a sideways motion, pry the old plug out. Throughly clean the area where the new plug will rest. Do not use anything that will damage the surface. A wire brush works well. Any nick on the mating surface will cause a leak. Now position the new plug in the hole and with a wooden dowel pin, or the end of a plastic hammer, about 50% the size of the plug, placed dead center on the plug, hit it sharply with a hammer and drive it home. You can also use a 1/2" extension if you are careful. Once it flattens out, stop. If all went well, you cleaned the surface, and did no damage in the process, you will have a good seal and no leaks. Good luck!