I have a 2001 530I . It ran hot while on the highway. I drove the car an additional 3 miles, when I got to my job the car was hotttt. I drive a truck so I went on out on the road assuming the engine was done. When I got back five days later. I added coolant , the car started and ran normally. ( no codes ) one thing I noticed the resivor was cracked. I had the resivor replaced and the car ran fine didnt over heat or anything. a month later its running hot. Is this a head gasket ? Now Ive heard that it is better to replace the engine in BMW vs doing a head job ? is this true ? Thank guys in advance ! ps the car has 125000 on it.