I dont know what happened in your case. The gasket might not be pushed into the slot correctly, or maybe they didnt tighten the bolts in sequence. If they tightened all the top bolts first then the bottom bolts, it could have messed up the gasket. Just like with all tightening, you want to try and even it out, like do the center ones, then a few on one side, then a few on the other side. I dont know if thats what happened...but its a possibility, ya just never know. I didnt do anything special when i put it all back together. Just made sure the gaskets were in place, I didnt use any extra stuff, like rtv or gasket maker or anything like that.