Despite the proliferation of signs in various repair shops urging customers to have their engines cleaned, the practice can actually leave car owners in hot water, said Jeffrey Boone, approved auto repair specialist, Towson office of AAA Mid-Atlantic, headquartered in Wilmington, Del.“That can be very dangerous,” Boone said. “There are certain places in a car engine that will let water in but it won’t let it out.”It’s also not a good practice to attempt a do-it-yourself engine cleaning. Most engines don’t need to be cleaned, Boone said. As most people know, modern cars are controlled mainly by computers within their engines. The computers can be damaged by water.“If somebody doesn’t know what they are doing [when cleaning an engine”>, that can be very dangerous,” Boone’s colleague Ed Kriston said.However, there are some situations in which cleaning an auto engine is a good idea. One is when an engine has a leak that allowed oil and dust to cake on. Cleaning the engine will allow it to run cooler, Kriston said.But again, it’s foolhardy for laypeople to attempt to clean the engine themselves. Certified technicians who properly clean engines use special cleaners and generally rinse the car’s engine with a gentle spray. Another reason to use a qualified technician for such cleaning is to protect the environment. Not only will the wash consist of mainly recycled water, which has been filtered, but it also will keep oil in a separate canister for proper disposal News source: Examiner