Car: 1995 Caprice Classic. I was swapping out the thermostat on my pump (Gates). When I went to reattach the gooseneck housing the bolts had become stuck about half way down. Never had this issue. Suddenly one bolt broke. I cannot get it out. Broke numerous drill bits included a higher end one. Further problem is I ordered what I thought was the right size replacement bolt (GM 22539278) but it's slightly too big. Does anyone know the correct bolt size and or model no? And is the threading issue heat related? Poor machining? Something else? Been stuck for over a week now.