Autonomous Motion

Red Line SI-1 Engine Detergent


Detergent-based fuel additive cleans car engine

Various engine-cleaning gas tank additives claim to remove carbon deposits from the engine, including from the vulnerable fuel injectors, resulting in smoother idling, better mileage, and more power. These contain detergents of the PEA (polyetheramine) category, originally developed by Chevron and sold as Techron.

A highly liked (355 upvotes) Amazon reviewer, Glenn Carpenter, tested several engine-cleaning fluids in a car whose onboard computer system reported figures that allowed him to estimate the cleanliness of the injectors. He found that all fluids were effective in quickly cleaning injectors. He settled on Red Line SI-1because he estimated it contained more PEA per dollar than competitors.

He also determined that the amount of detergents contained in gasoline is too low to be effective, and that engine cleaners not containing PEA were not effective either. (However, the Lucas Oil 10512 Fuel System has some knowledgable fans on Amazon.)

I added a third of a bottle (i.e., 5 ounces) to my half-full gas tank. Within a dozen miles the idle’s roughness was gone. I haven’t driven far enough yet to test its other claims, but reviewers on Amazon report good results in those departments. It’s rated at 4.5 stars there, on 322 reviews.

-- Roger Knights 03/22/16