The decision to have a professional service clean a car engine, or go the do it yourself route depends on the recommendation of the car's manufacturer, and the technical skills of the car owner. Manufacturers of some car models advise against engine flushing. Steam cleaning is also risky.
Car owners should thoroughly research the pros and cons of cleaning the car engine and check whether it is safe to do so. Owners can contact the car manufacturer directly for more information about engine cleaning for a particular make or model. Engine flushing and steam cleaning done by a service, or the car's owner, may do more harm than good. For instance, GM and Honda don't include engine flushes in recommendations for car maintenance. Flushing the engine can cause particles to clog other engine parts, which may permanently damage the engine. Likewise, steam cleaning a car's engine can extend its life, but it can also cause serious damage. Steam cleaning the engine can ruin a car's electrical system, damage the ignition and ruin the air-intake system.
Some car maintenance services pressure car owners into engine cleaning that ends up harming the car, however, it may be okay to clean the engine of some car models. Doing a detailed cleaning involves numerous steps that must be done correctly to avoid damaging the engine.