I had work done to the top of my crankshaft and now all of a sudden the bottom half is screwed up. Could that of been caused by poor work by the macanic?

 

Top? Bottom? Not sure what you mean,what exactly did you have done?
There's not much you can do with a crankshaft without taking the motor apart and having the crank out and in a machine shop,what do you mean by top and bottom?
I've never heard of a crank having a top and a bottom.

 

the crank has bearings for the mains, facilitating the smooth operation of the rotating mass. And bearings on the throws for connecting rods. The tolerances are critical. Too loose and you will see lower oil pressure. Too tight and you won’t have the oil film needed and you’ll likely spin a bearing.

there’s a front seal which is typically trouble free. The rear seal setup on LS engines is prone to leaks. Bad design.

describe the problem please.

 

what did the mechanic do ?