The oil capacity for a 1989 Cadillac depends heavily on the *specific model* and *engine*. Cadillac offered several models (e.g., DeVille, Brougham, Fleetwood) and various engine options (V6, V8) in 1989.
You'll need to consult your owner's manual for the precise oil capacity. The manual will list the capacity for your exact Cadillac's engine.
Without knowing the specific model and engine, I cannot give you an accurate answer.
