I brought my car in the repair shop to resolve some oil leaks in the engine compartment. I've had the following parts replaced, oil cooler seals & housing, valve cover gasket and seals...etc. Prior to getting work done one my engine, the car was over heating. Upon completion of the engine work it was low powered and gives a hard start.

I've replaced the oxygen sensor but the problem still exist, now I've been told that the battery need to replace for the one currently on it isn't compatible.

What can you recommend to resolve this issue.