Engines aren’t supposed to rumble. Engine parts are designed to interact with each other seamlessly, so when you crank the ignition, step on the gas, or idle at a stoplight, your vehicle feels silky smooth. Motor oil and other fluids make this possible.

But they’re not enough to combat carbon deposits on top of an engine’s pistons. Carbon builds up here as a result of fuel burn off, and if unchecked this carbon buildup can reach the intake valves. If that happens, engine compression can change, and valve seats may not seat properly. This can cause several problems, such as poor acceleration, rough idle, decreased fuel economy, or worst of all: engine failure. And if you think these problems are exclusive to your classic fixer-upper, think again. They can happen in lower mileage vehicles, too.

Until recently removing carbon buildup was especially arduous in modern engines such as gasoline direct injection (GDI) engines. There are over 35 million GDI vehicles on the road today, and in the past cleaning engine valves required invasive methods such as dismantling the engine, cleaning the valves manually, and putting the whole thing back together. This process could take several hours and more than several dollars.

We figured there must be a better way. So, our scientists donned their white coats, snapped their rubber gloves, pulled on their lab goggles, and got to work. After tinkering and toiling, First Defense was born. First Defense is a cleaning service that carries detergents through the intake, to the intake valves, into the combustion chamber, and right to the deposits. When it gets there, the product dissolves them.

It may sound simple, and that’s because it is. Thanks to First Defense, a cleaning process that would consume eight or nine hours can happen in less than one. Plus, it’s easier to perform, so more mechanics can do the procedure. All that’s needed are basic tools, a simple canister apparatus, and shop air. Ah, chemistry.

The product works efficiently, but that doesn’t mean it was easy to make. For a long time, people thought this type of product was impossible. All Engine Clean was the result of many years of development. It’s Valvoline’s most effective product for a complete cleaning of the fuel system in modern engines, including this with GDI engines. And sometimes when you find a winner, you stick with it.