The great news is the heads always crack, so you will do good to get a new one.

Man I miss my 87 300D, she could float down the highway at 120 mph, a real hell of car, but just not as simple as the 85 W123 versions. But what a money pit, the control arms bushings need to always be replaced. the vacuum system for the CLS is problematic, too many gizmos, new blower motor, new aux pump, new vacuum pds and that damn aluminum head. A great car and very powerful but a real money pit....I am glad I sold mine and kept my 85 300D instead