Rebuilding 3-Series engine
 

I'm new to this forum. Would appreciate it if there is already a topic on this, please direct me to it. My engine siezed and I will need to have it rebuilt. I have spoken to my mechanic. He says two options: find a used motor or rebuild it. One major issue with a used motor is an oil leak which he says will not surface for 3-6 months after. Is he correct? And should I go with a rebuild? How much will it cost? or should I go with a used engine? and how much will that cost?

could you clarify what is the car? year and engine.