Will not start, oil drip on crankshaft?

Hello, I will explain as best as I can. Thank you in advance for your time.
Engine light came on, showing camshaft code. The guy at the parts store said 97 doesn't have one, so replace the crankshaft. Did that, it started once and would not start moments after. A mobile mechanic looked at it today. Cleaned the crankshaft and area off and it started. Again, moments later it wouldn't. He then noticed oil on it. Said the oil drip is disrupting the connection pretty much. Didn't look like a crack in the engine, said it is probably coming from a bad seal. Said it is too big of a job for him as the transmission would have to come out to access it. I spoke to someone briefly who hasn't looked at it but said a drip of oil shouldn't make it not start that quickly. So, I guess my question is. Have you experienced this? Can it be just the drip causing it not to work? If so, do you have any idea what the job should cost in general? I'm in central NC.