Just bought a B7100 with a D750a engine. The seller story goes like it was parked for about six years since husband was no longer capable to drive it. Someone about a year ago tried to start it and turned the intake hose upward and left. I’m sure some rainwater got inside Intake. I removed intake manifold and see debris and rust inside the block. I filled the intake on the block with mystery oil. What should I expect? Should a try to start this? Is it doomed?