Hi I am have a 96' Oldsmobile Ciera series II 4door with 79K. With 3.1 series 3100 V6. I just found out why car was using coolant for the last six month's. It appear's that one gaskets is letting coolant out the top of the engine. The mechinic said in could be the Intake mainfold upper and lower, head gaskets or the throttle body gasket's. I am wondering which gasket it is? I am wondering how common this problem is? I also like to know how time (aka work is involved to fix). And Lastly how other engine damage I might have. By the way I had checked my oil and it does not show any signs of contaimintation (the oil looking cholatety, or thick and murky).