My 94 ranger started leaking out radiator fluid yesterday. I was thinking it was coming from the water pump so I started tearing down the front of the engine. Once I had everything off I noticed the freeze plug (right front head) had a small hole in it. My coolent is very rusty what could have caused this? I guess I should go ahead and replace all the plugs in it. I cant remember do i have to have a machine shop press in the plugs or can I do it myself? thanks.