Where are you located? I have a 300E parts car that you could get the engine cheaply from. 1990 M103.

You can use a long screwdriver with a plastic handle as a stethescope, Hold your ear on against the plastic handle and touch different places on the engine until you find where the ticking is the loudest.

See if the oil pan is simply dented in. If so, it could be taken off and hammered back, or go to a body shop and see if they would pull it out with a unispotter.

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1959 Gravely LI, 1963 Gravely L8, 1973 Gravely C12
1982 380SL
1978 450 SEL 6.9 euro restoration at 63% and climbing
1987 300 D
2005 CDI European Delivery
2006 CDI Handed down to daughter
2007 GL CDI. Wifes