So I am prepping my cracked block for the JB-Weld miracle to come, and having a problem with coolant still seeping out of the crack. I drained the radiator two months ago, still I have this seepage. So I opened a petcock that sits alongside this crack, expecting it to be a drain for the water jacket. Petcock is low on the block, driver's side far back, maybe 3 inches above the oilpan. Nothing comes out at all. So I take off the petcock, which is pretty well thick with black gunk, and clean out the hole which is also full of black gunk. Still no coolant runs out of that hole, but my cracked block still seeps. So what is this petcock for? and how do I thoroughly drain the water jacket?
