Replacing all of the belts and the water pump on my 1993 van. Everything went pretty smoothly, really. I got it all put back together, started the engine, and oil started pouring out onto the ground, seems like it's coming from behind the water pump. I took the belts off, removed all the timing covers, and reinstalled all the belts and tensioned them, then started it back up without any timing covers, to confirm whether there is any oil coming out of the seals. The new crankshaft and camshaft seals are NOT leaking, but oil is dripping rapidly from around the new water pump's drain plug (which is installed quite tightly) and seems to be coming out from between the water pump and the engine block. It's definitely coming out of the lower dowel pin hole, which is of course a useless +0.7 mm oversized cast hole (not reamed or even drilled) in this Chinese knock-off water pump. But apparently all replacement water pumps for these vehicles share this construction, and nobody else is having huge oil leaks like I am seeing. While removing the old water pump, I did notice a few drops of oil coming out along with coolant that puddled on the floor. I assumed this was oil from the old camshaft seal that leaked and got trapped in the nooks and crannies around the old water pump. I may have been wrong. Where could the oil be coming from? The only fluid that's supposed to flow through the water pump is water/coolant, right? No oil. Why would the water pump leak oil?