Compression leak and coolant sensor in 2013 s60

[gowriprasanth]

Hey all, I would like to know what could be the reason for the compression leak in my cylinders 3 and 4 ( 84 and 87 psi ) other than the head gasket, and also my coolant sensors are disconnected as well. But the car runs great with 120k miles. Also had changed the head gasket and resurfaced the head. But the engine now lacks compression in all cylinders. I have no idea what was going on and now the mechanic says that valves are bent because of timing. But before that I drove the car and everything was expect 2 cylinders. I need to know what's the exact issue going on ?