A compression and/or pressure test of the cylinders will tell a lot about the possible damage. Or, if you do not own a compression gauge or the tools to do a pressure test, then you can monitor the coolant level in the radiator to see if the engine begins using coolant. If you have the coolant level marks in the radiator, then use those, if not then a ruler can be used. Or, if the engine begine to run hotter than before and/or the engine gets hot when idling (and the coolant level is correct) then suspect the head gasket has been damaged.
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