Engine additives are to cars what protein powders are to gym-goers: passionately praised by some as essential for performance, dismissed by others as mere hype or snake oil.
Although modern synthetic oils meet API specifications and standards and do offer superior protection versus their conventional counterparts, operating conditions considered extreme, such as frequent towing or driving in excessive heat or cold, can tax your engine more than normal. In such situations, you may want to consider an additive. Similarly, if you have a high-mileage vehicle, certain additives can help keep the engine in tip-top shape.
The three additives below can provide a number of benefits for your engine, from increased fuel economy to improved cold-start performance. Each is readily available on Amazon, and none are overly expensive, given the long-term protection they can offer.
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Zinc Dialkyldithiophosphate (ZDDP)
Concentration is key
ZDDP is a polar compound attracted to iron and steel surfaces, serving as an industry standard for high-pressure and anti-wear protection since the 1940s.
- How it Protects: ZDDP is heat-activated. Under the high-load conditions found in the valvetrain, the compound decomposes to form a microscopic, glass-like polyphosphate “tribofilm.” This sacrificial layer prevents metal-to-metal contact when the primary oil film is squeezed out by extreme pressure.
- What it Protects: Vintage engines (pre-1990s) with flat-tappet camshafts and high-performance engines with heavy valve spring pressures. ZDDP can also be recommended during the engine break-in period for rebuilt motors.
- When to Apply: Add ZDDP after each oil change to ensure ongoing protection. Concentration is key. A single 11 to 12 oz bottle per five to 5.5 quarts of oil is sufficient to raise zinc levels without damaging the catalytic converter. Be sure to read the directions, as some model-year vehicles and engine types (i.e., diesel, marine, and motorcycle) may require different amounts.
- Brand
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Rislone
- Liquid Volume
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11 fluid ounces
Rislone Hy-per Lube is a “booster” that stabilizes and restores an oil’s zinc and phosphorus levels, protecting critical engine components like camshafts and pistons from friction and wear. Lower friction levels mean less heat and more resistance to things like viscosity and thermal breakdown.
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Rislone Hy-per Lube is often described as a “booster” that stabilizes and restores an oil’s zinc and phosphorus levels, protecting critical engine components like camshafts and pistons from friction and wear. Lower friction levels mean less heat and more resistance to things like viscosity and thermal breakdown.
For collectors and enthusiasts with hot rods and race cars, Lucas Oil offers a break-in additive for those types of high-performing engines to protect things like the camshaft and valvetrain.
Stop letting your car warm up in the morning—it’s a waste of gas
More of a psychological benefit than a mechanical one.
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Molybdenum Disulfide (MoS2)
Reduces engine wear and tear
Commonly known as “Moly,” this inorganic mineral compound provides solid-film lubrication in environments where fluid-film lubrication (i.e., the oil itself) might be insufficient. Noted benefits include a quieter and more fuel-efficient engine, especially for those with higher mileage.
- How it Protects: MoS2 consists of hexagonal crystal layers that slide easily over one another. The particles bond to cylinder walls and bearings, forming a low-friction layer. MoS2 provides additional protection during dry starts before the oil pump pressurizes the system.
- What it Protects: High-mileage engines or vehicles subjected to heavy use, such as work trucks or vans. This can include frequent short trips in cold weather, regularly towing a long trailer (i.e., fifth-wheel or gooseneck), or driving frequently with a payload.
- When to Apply: After an oil change, shake the bottle well for a few moments before pulling the tab out of the bottle. After pouring the additive into the oil filler neck, drive for at least 20 minutes to allow the particles to circulate and bond to the internal surfaces of the engine.
- Brand
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Liqui Moly
- Liquid Volume
-
10.1 fluid ounces
Liqui Moly MoS2 Anti-Friction Engine Treatment is widely regarded as an industry-standard Moly additive to reduce engine wear and tear. While its primary use is likely for a vehicle engine, Liqui Moly can be used for lawnmower, snowblower, and ATV engines.
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Liqui Moly MoS2 Anti-Friction Engine Treatment is widely regarded as an industry-standard Moly additive to reduce engine wear and tear. While its primary use is likely for a vehicle engine, Liqui Moly can be used for lawnmower, snowblower, and ATV engines.
Liqui Moly Cera Tec is a premium option that combines MoS2 with micro-ceramic particles for enhanced friction reduction, effective for up to 30,000 miles.
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Polyetheramine (PEA)
Remains stable during combustion
PEA is a nitrogen-based detergent formulated to prevent engine knock and low-speed pre-ignition (LSPI), also known as “super knock.”
Engine knock typically occurs after the spark plug fires, caused by pockets of air-fuel mixture detonating elsewhere in the cylinder due to high heat or low-octane fuel. Although modern engine control units (ECUs) can reduce engine knock, it still results in power loss and stress on internal components.
LSPI is a more pronounced version unique to modern turbocharged gasoline direct-injected (TGDI) engines. It occurs when the air-fuel mixture ignites before the spark plug fires, typically at lower RPMs but under higher demand, such as during quick acceleration from a stop light. LSPI is often triggered by microscopic oil droplets or glowing carbon deposits that act as unintended ignition sources in these situations. Because it happens while the piston is still rising, the resulting pressure spikes (often exceeding 3,000 psi) can cause shattered pistons and bent connecting rods, among other issues.
- How it Protects: Unlike solvent-based cleaners that may evaporate, PEA remains stable during combustion and dissolves carbon deposits on fuel injectors, intake valves, and combustion chambers.
- What it Protects: PEA can be used as a preventative maintenance item every 3,000 to 5,000 miles if you own a vehicle with a TGDI engine.
- When to Apply: Add the PEA cleaner to a nearly empty fuel tank before pulling up to the pump. The force of the incoming fuel stream ensures a homogeneous mixture. After filling up, take a short drive at highway speeds.
- Brand
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Chevron
- Liquid Volume
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20 fliud ounces
Chevron Techron Concentrate Plus is a PEA cleaner for routine fuel system maintenance, formulated to smooth out rough idles and restore lost power.
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Chevron Techron Concentrate Plus is a PEA cleaner for routine fuel system maintenance, formulated to smooth out rough idles and restore lost power. Another popular option is Gumout Regane, a high-mileage fuel system cleaner that helps remove stubborn deposits in older engines.
Good maintenance goes a long way
By understanding different additives, DIY vehicle owners can extend the lifespan of their engine by a good margin. The difference between a vehicle that reaches the 100,000-mile, 200,000-mile, or even 300,000-mile mark is rarely a matter of luck. Instead, it is a steadfast commitment to routine service and maintenance.
By matching the right compound to a specific engine and its operating conditions, drivers can ensure their powertrain remains efficient and reliable for years to come.
