Like anything else, engines work better when they’re clean. But cleaning an engine is not the same as cleaning the rest of your Saab. With the right procedure, you can keep your engine in tip-top shape. No need to hire a professional; you won’t need anything you can’t find lying around the house.
Of course, first of all, Move the car to an area where the soap and material cleaned off will not cause damage or enter a storm drain.
Then, Cover any exposed electrical components with a plastic bag or plastic wrap. Cover the breather or air intake and carburetor on older engines with heavy aluminum foil or plastic. Then start cleaning. Author recommends use of petroleum- or alkaline-based degreaser depending on how much dirt.
The same procedure should apply to almost any car, however the precaution with covering the engine block apples to most direct-injected Saab gasoline engines, including the Saab 900, Saab 9000 and Saab 9-3.