need engine replaced after getting engine power flush

To sue the auto lube place you would need an expert (mechanic) who would testify in Court that the auto lube was negligent and that the damage to the engine was the result of their negligence. Hiring a good mechanic who would testify could be expensive. I suggest you start by filing a complaint with the County's consumer protection agency; they work for free and frequently get results in automobile repai cases.

You must prove that the engine flush caused the engine to fail--a difficult proof, I think. Did the dealer tell you why the engine needed to be replaced? Is it possible that the auto lube place did not replace the oil plug and the oil drained out of the engine. Were any engine lights on after the oil flush? I recommend that you get a written diagnosis report from the dealer and then write to the auto lube place and make a complaint. If the dealer links the engine failure to the engine flush, you can sue the auto lube place in small claims court.