more than likely due to LIM gasket failure resulting in milkshake like oil causing...your problem. it isn't really the engine itself at fault, it'* the poor design of the stock LIM gasket (which have been revised). this is in regards to the 3400 btw.
Wow I think I should listen when women talk lol. The car is a 2000 Malibu not Impala lol. Her mechanic says $3600 tio fix it, parts and labor. Not sure if this means a new engine or just a short block.
same engine really, just smaller pistons. both are prone to the same LIM gasket problem. you can buy good runnning ~50,000 mile 3400s or 3100s for less than $500. $3600 is crazy. a 3400 would drop right in place of the 3100