I have a leak on my truck that has got me wondering. It is coming out of what looks like a blind tapped hole. There are actually 2 of these holes vertical of one another, and are located on the front of the block below the alternator and just an inch or two beside the timing cover. My question is what are these holes for and more importantly why do I have oil leaking out of one of them? It is a 1976 block if that helps. Thanks in advance guys.