First off. Newb here. So I did the rad then the water pump and as I finished the water pump, I started adding coolant. Then I hear dripping. So I Jack it up and get underneath to look for where it's coming from and I look at the bottom of block in between the oil and tranny pans and find my self looking at two silver circles one of which seems to be leaking around the seam. Is this piece replaceable or is it just part of the block?