Turn the engine over by hand. On my 1985 300D, I can do that easily with a 22 mm wrench on the power steering pump pulley at the top of engine. If you feel each cylinder strongly resist you over 2 revolutions, indeed must wait for each to hiss down, the engine is basically fine with no valve, head gasket, nor piston ring problems.

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1984 & 1985 CA 300D's
1964 & 65 Mopar's - Valiant, Dart, Newport
1996 & 2002 Chrysler minivans