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Twelve filled 1-quart bottles (32 fl oz each). Boosts cetane by 5–7 points, improves fuel economy and adds fuel-system lubricity. Treats up to 7,680 US gallons at 1 fl oz per 20 gallons; 3,840 gallons at 2 fl oz per 20 gallons.
Opti-Lube Summer+ Cetane Diesel Fuel Additive — 1-Quart Bottles — 12-Pack
Product data
| SKU | OPT-SPQRT12 |
| Formula | Summer Lube+ Cetane (yellow label) |
| Package contents | Twelve filled 1-quart bottles (32 fl oz each). |
| Additive volume | 384 fl oz total; 32 fl oz per filled container |
| Fuel type | Diesel fuel; compatible with ULSD and biodiesel |
| Warm-weather label rate | 1–2 US fl oz per 20 US gallons of diesel above 32°F (0°C) |
| Lower-rate package capacity | Up to 7,680 US gallons at 1 fl oz per 20 gallons (1:2,560) |
| Higher-rate package capacity | 3,840 US gallons at 2 fl oz per 20 gallons (1:1,280) |
| Per-bottle treatment | Up to 640 US gallons at the lower rate; 320 gallons at the higher rate. |
Benefits and performance
Opti-Lube Summer is the Best Diesel Fuel Additive for Everyday Use.
Opti-Lube Summer+ Cetane Formula Diesel Fuel Additive is designed to enhance the performance and quality of ultra-low sulfur diesel (ULSD). This multi-functional additive helps increase lubricity, improve fuel mileage, and support overall engine performance. By providing additional lubrication within the fuel system, it helps reduce wear on critical components such as injectors and fuel pumps while supporting smoother engine operation. It also works to clean injectors, help prevent future deposits, and support a cleaner fuel system.
This formula boosts cetane by up to 5 to 7 points, supporting improved ignition quality, smoother operation, and reduced engine noise. By improving combustion characteristics and reducing ignition delay, it helps promote a more complete burn, which may support improved fuel economy and efficient engine operation. It also helps reduce deposits and emissions while providing protection against rust and corrosion. This package treats up to 7,680 US gallons at the lower label rate and supports fuel stability while helping maintain overall fuel quality.
Key Features:
- ENHANCED LUBRICITY & PROTECTION: Diesel fuel additive designed to increase lubricity of ultra-low sulfur diesel (ULSD), helping reduce fuel system wear and protect injectors, fuel pump, and engine components for reliable and consistent performance.
- IMPROVES FUEL ECONOMY: Summer+ Cetane diesel additive shown to enhance fuel mileage year round by supporting efficient combustion, helping maximize fuel usage while supporting engine power and overall diesel engine performance.
- CLEANS & MAINTAINS INJECTORS: Fuel injector cleaner additive that helps remove residue, prevent future buildup, and maintain injector cleanliness. Supports reduced deposits and emissions while helping prevent rust and corrosion in the fuel system.
- ENHANCES PERFORMANCE & STORAGE: Multi-functional diesel additive that supports engine performance in all conditions, helps separate water from diesel fuel, and more than doubles the storage life of standard diesel fuel for consistent operation.
- SUMMER FORMULA FOR WARM WEATHER: Designed for higher temperatures, this diesel fuel additive helps reduce thermal fuel breakdown, maintain fuel quality, and support reliable engine operation during summer driving conditions.
The Summer+ label states: cetane improved by 5–7 points; over 21% increased lubricity for reduced system wear; improved fuel economy; reduced deposits and emissions; improved storage stability that more than doubles the life of diesel; injector cleaning; rust and corrosion prevention; and improved water separation.
Treatment and use
The warm-weather label rate above 32°F (0°C) is 1–2 US fl oz per 20 US gallons of diesel. Use the higher listed rate for maximum cetane and quicker fuel-injection clean-up. For example, 20 gallons takes 1–2 fl oz; 40 gallons takes 2–4 fl oz. The advertised “up to” coverage uses the lower rate. All volumes are US measures.
Summer+ may be mixed with other Opti-Lube diesel fuel additives as stated on its label; follow the directions for each formula. Choose appropriate cold-weather protection when needed.
Read the product label and Safety Data Sheet for complete handling, storage and safety precautions. Continue normal fuel-filter and water-separator maintenance.

