I believe the m103 and m104 shared the same block, the difference was in the cylinder head and injection system.
You should have a drain in that location.

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"It's what non-car people don't get. They see all cars as just ton-and-a-half, two tons of wires, glass, metal and rubber. That's all they see. People like you or I know, we have an unshakable belief that cars are living entities..... You can develop a relationship with a car, and that’s just what non-car people don't get."
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