Fuel Additives

mongst many technicians and the general vehicle owning public, fuel additives get the proverbial ‘bad rap.’ It’s not hard to see why that happens. Too many times, one comes across print or late-night television advertisements claiming a particular additive product will help not only clean a vehicle’s engine, but boost performance and increase fuel economy to levels greater than what the vehicle ever had, even when new. When put to the test (objective scientific tests, not ‘claims’ made by the manufacturer) those additives fail spectacularly. So it is not surprising that many have a skeptical attitude towards the usefulness of additives.

Makers of fuel additives know all about consumer’s skepticism and say people are right to question the exaggerated and unprovable claims made by some makers of additive products. What they point out is proper fuel additives use the same cleansing formulations found in gasoline that one pumps at the filling station. Since 1995, the Environmental Protection Agency (EPA) in the United States has mandated fuel additive standards in an effort to lower harmful vehicle emissions by improving engine performance. The additives include detergents, corrosion controls and demulsifiers, and metal deactivators (in this issue of SSGM Magazine, one can read more about this in the CARS onDemand article by Chuck Carman on page 23).

“In fact, refinery fuel additives are a U.S. government-mandated part of the fuel blends that each of us pump into our vehicles,” says Matt Erickson, P.E., mechanical engineer, product manager-passenger car with Amsoil Inc. in Superior, WI. “They play an important role in maintaining engine cleanliness and emissions.”

So why bother then with fuel additives?

“There are two main reasons,” says Dietmar Schmid, application engineer at Liqui Moly in Germany. “There are additives for preventative use in order to keep the original performance and fuel economy of the car, and to protect it from the build-up of deposits.”

The build-up deposits are a normal part of an engine’s life. Fuel combustion inside an engine is not perfect and leaves behind soot, ash, fuel residues and other contaminants. Over time, these deposits build up, especially on valves and injectors, and affect the performance of the engine. “(The deposits) absorb fuel when the engine is still cold, altering the proper air/fuel ratio,” says Erickson. “It can also disrupt air flow into the cylinders and cause the valves to stick. Deposits that accumulate on fuel injectors cause an irregular spray pattern making the air/fuel mixture to be less efficient for burning.”

Deposits that accumulate inside the combustion chamber can cause excessive temperatures that can lead to pre-ignition or knocking, or the deposits in the chamber can ‘flake off’ and become stuck between the exhaust valve and seat, causing it to slightly stick open, adds Erickson.

“Usually, the build-up of deposits is a slow process, often not noticed by the driver,” says Schmid, except as a diminishment of engine performance over time. “In the end, these deposits may even kill an engine. Liqui Moly investigated several cases in Denmark where, due to deposits, the injector did not spray the fuel anymore, but emitted a thin line of fuel, thus melting a hole in the piston head.”

“Modern engines with their optimized fuel economy and electronic control system are more prone to get problems due to deposits than with older technology,” Schmid continues. Modern engines are far less tolerant towards disturbances of the combustion.”

What properly formulated fuel additives do is remove those deposits while not harming critical engine components. This is an artful balance.

“Amsoil P.i. Performance Improver works by cleaning everything the fuel touches, including fuel injectors, intake valves and combustion chambers,” Erickson says. “It removes deposits that have built up over thousands of miles. Comprehensive product testing has been done to ensure that it is safe to use and it is effective in cleaning engines.”

The challenge for service shops is making the use of fuel additives a part of the maintenance schedule.

“Additives are a great opportunity to generate additional sales and to get happy customers,” Schmid says. “It may be a good idea to offer and explain additives to everyone bringing in their car for an oil change or inspection. A shop can offer a fuel cleaning in combination with an oil change.

“Imagine a customer has a car suffering from deposits. The shop used to have two options: either make the car owner accept the situation or clean the injectors manually. Now, they do not need to take a brush in the hand, but use cleaning additives as a chemical brush. You achieve the results without much investment in labour and the customer is happy just to pay a few dollars to get the problem solved.”