High Sales
One of the big moneymakers for service centers is selling and recommending preventive services. These aren’t really scams, but more like drive-thru super combo meals.
Should you “flush” your car’s cooling system, fuel injectors, or transmission? Probably not, but in most cases it won’t do any harm. Refer to your owner’s manual or Haynes manual for recommended maintenance intervals. A cooling system flush is likely and will probably only be needed every few years. When it comes to automatic transmissions, the current consensus is that washing them after extended use is actually worse than draining and refilling them.
Cleaning the throttle body or flushing the injectors is usually not necessary. On some engines, dust and oil fumes can build up on the throttle mechanism. Thanks to new air and intake filter designs, this is a thing of the past and is now a rare occurrence in products manufactured in the last 15 years. Modern fuels contain so many cleaning agents in the injectors that they remain clean simply through operation.