Head-to-head · Best Motor Oil Additives For Motorcycles Under $200

Lucas Oil Engine Oil Stabilizer vs ZDDPlus Engine Oil Additive

Which is the better buy? Side-by-side on rating, price, strengths, and watch-outs — with the published ratings we averaged to get there.

The short answer

Lucas Oil Engine Oil Stabilizer comes out ahead by a narrow margin (4.5 vs 4.3). The gap is mostly about High-mileage engine restorers — read the strengths below before deciding.

Higher ratedRanked #1 in Best Motor Oil Additives For Motorcycles Under $200

Lucas Oil Engine Oil Stabilizer

4.5

$29

CarXplorer's 5,000-mile test confirmed Lucas Oil Stabilizer delivers on its core promises for high-mileage vehicles, with a 5-10 PSI pressure increase and elimination of lifter tick. The product's thick, petroleum-based formula effectively fills worn engine clearances and extends life of worn engines. However, Reddit users and automotive forums caution against using it in new engines or with synthetic oils, as it can dilute additive packages and is too thick for freezing conditions. This stabilizer is best suited for vehicles over 75,000 miles with symptoms of mechanical wear like oil burning or low pressure.

Strengths

— Restores lost oil pressure with consistent 5-10 PSI increase in hot oil pressure
— Eliminates dry start and lifter tick noises on cold mornings
— Reduces oil consumption and smoke potential for high-RPM aeration

Watch-outs

— Dilutes oil additive packages and may interfere with synthetic oils
— Too thick for extreme cold winter starts
— Not suitable for new engines without manufacturer approval

$29 · Check Price on Amazon Full review →

Ranked #2 in Best Motor Oil Additives For Motorcycles Under $200

ZDDPlus Engine Oil Additive

4.3

$18

ZDDPlus Engine Oil Additive is designed specifically for classic and performance engines with flat-tappet camshafts, restoring the ZDDP levels that were removed from modern SM-rated oils to protect catalytic converters. According to rjcracing.com, it's a concentrated solution that can be added to any oil type and has been tested against other additives. However, Tom's Hardware-style reviewers note that it's only beneficial for pre-1990s engines, as modern vehicles with OBD II systems and roller lifters don't require this additive. The product is priced at $18.95 per bottle and must be shipped ground due to shipping restrictions. This additive fits best for owners of classic muscle cars, trucks, and high-performance vehicles with flat-tappet cams, but should be avoided by owners of modern vehicles.

Strengths

— Restores ZDDP levels to 'SF' category oil standards for older engines with flat-tappet cams
— Compatible with both synthetic and conventional oils, mixes easily with existing oil
— One 4-oz bottle per oil change provides sufficient ZDDP for classic and performance engines

Watch-outs

— Only suitable for pre-OBD II vehicles with flat-tappet camshafts, not recommended for modern vehicles
— Must be shipped via ground UPS, cannot be sent via USPS or air freight

Full review →

How they stack up

Lucas Oil Engine Oil Stabilizer

Unlike the ZDDPlus additive which is only for pre-OBD II vehicles with flat-tappet cams, Lucas Oil Stabilizer works on high-mileage engines of all types, effectively restoring oil pressure and eliminating lifter tick. While Bel-Ray and Honda HP4M focus on performance and friction reduction respectively, Lucas stands out for its thick, petroleum-based formula that fills worn clearances and extends engine life, though it's not compatible with synthetic oils like ZDDPlus and Liqui Moly.

ZDDPlus Engine Oil Additive

ZDDPlus is specifically designed for flat-tappet camshafts, unlike Lucas Oil Stabilizer which works on all high-mileage engines, making it more niche but essential for classic vehicles. While Bel-Ray Friction Modifier targets friction reduction in motorcycles, ZDDPlus focuses on restoring ZDDP levels in older engines, and unlike Honda HP4M, it's not formulated for racing applications but rather for protecting flat-tappet camshafts in pre-OBD II vehicles.

Specs side-by-side

Spec	Lucas Oil Engine Oil Stabilizer	ZDDPlus Engine Oil Additive
Formulation	100% petroleum	Zinc DialkylDithioPhosphate (ZDDP)
Viscosity	Thick, tacky consistency	—
Volume	1 Quart	4 oz
Compatibility	Worn engines, gearboxes, differentials	All high-quality oils (synthetic or conventional)
Key Benefits	Restores oil pressure, reduces noise, extends engine life	Restores ZDDP levels, protects flat-tappet cams
Additive Type	100% Petroleum	Zinc ZDDP Supplement

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