85 ft-lbs on a housing that calls for 35 in-lbs is about 30 times too much, so yeah, that aluminum is going to give somewhere. I've seen those housings crack right at the bolt flange before the motor ever warmed up, usually hairline cracks that only weep once things get hot and the metal grows. The flat O-ring is often the first sign, then the crack shows up later when you pull it apart. Pressure test it cold and hot before you call it done, because a crack you miss now will bite you down the road.