Fuel System Cleaners Compared: Techron, BG 44K, Red Line SI-1 and Berryman B-12

Most bottles on the additive shelf are mild detergents in a carrier fluid. A few contain enough of the right chemistry to change how an engine runs. The difference comes down to one ingredient and how much of it is in the bottle.

PEA is the ingredient that matters

Polyetheramine, usually shortened to PEA, is a detergent that survives combustion temperatures long enough to soften hard carbon. That is why it works on injector tips, piston crowns and combustion chambers, where weaker detergents burn off before they do anything. The well-known concentrated cleaners are built around it:

• Chevron Techron Concentrate Plus. Chevron developed PEA for fuel use and this is the consumer version. Sold by bottle size to match tank size.
• BG 44K and 44K Platinum. The can many repair shops add during a fuel service. Concentrated, and priced like it.
• Red Line SI-1. A high-PEA cleaner that also carries an upper-cylinder lubricant, popular with owners of older injected engines.

All three are used the same way: one container into a nearly empty tank, fill with fuel, drive the tank through. You can browse them together in fuel injector and fuel system cleaners, or by brand: Chevron, BG and Red Line.

Where a solvent cleaner fits

Berryman B-12 Chemtool is a different tool. It is a blend of fast solvents that dissolves gum and varnish, the sticky residue left by fuel that has sat too long. That makes it the better choice for a carburetor that has been stored, a small engine that surges, or a rough idle after a season of sitting. It is less suited to the baked-on carbon that PEA handles.

A practical rule: stale-fuel problems want a solvent, high-mileage deposit problems want PEA.

What direct injection changes

In a port-injected engine, fuel sprays onto the back of the intake valves, so anything in the fuel washes them. In a gasoline direct injection engine the fuel never touches the intake valves, so no tank additive can clean them. On those engines a cleaner still helps the injector tips and the combustion chamber, but intake valve deposits need an induction service or walnut blasting.

How often, and when

• For maintenance, once every oil change interval is the schedule most makers print on the label.
• For a specific symptom such as hesitation, a rough cold idle or a drop in fuel economy, use one full-strength treatment and judge the result over the whole tank.
• Many technicians add the cleaner on the tank before an oil change, since some of what it loosens ends up in the oil.
• More is not better. Doubling the dose does not double the cleaning; it only costs more.

What a bottle cannot do

A cleaner will not repair a leaking or electrically failed injector, a weak fuel pump, a vacuum leak or a failing coil. If a misfire code points to one cylinder and stays there after a treatment, the cause is mechanical or electrical. Diesel engines need their own products; see diesel fuel additives. For fuel that will sit over winter the right product is a stabilizer, covered in fuel stabilizers and treatments.

Frequently asked questions

Which fuel system cleaners contain PEA?

Chevron Techron Concentrate Plus, BG 44K and Red Line SI-1 are built around polyetheramine (PEA). It is the detergent that works on hard carbon in combustion chambers and on injector tips.

Is Berryman B-12 the same kind of cleaner as Techron?

No. B-12 Chemtool is a solvent blend that dissolves gum and varnish from stale fuel, which suits carburetors and stored engines. Techron is a PEA detergent aimed at baked-on carbon deposits.

Do fuel additives clean intake valves on direct injection engines?

No. In a gasoline direct injection engine the fuel does not pass over the intake valves, so a tank additive cannot reach them. It can still clean injector tips and the combustion chamber.

How often should I use a fuel system cleaner?

For maintenance, about once per oil change interval, following the label. For a symptom, use one full treatment and judge it over the whole tank.