The Tool Desk
Outbyte Driver Updater FREEFix the driver behind crashes, sound loss and screen glitchesFind Drivers →Outbyte PC Repair FREERepair Windows errors before they cause bigger problemsFix Now →No—don’t intentionally mix WD-40 Multi-Use Product with gasoline or use it as a fuel additive. WD-40 describes the product as a lubricant, penetrant, moisture displacer and corrosion protector, not as engine fuel or a fuel additive. If some has already gone into a tank, don’t start or continue running the equipment until you’ve checked its manual and obtained advice for that specific engine and amount.
Can you put WD-40 in a gas tank?
WD-40 Multi-Use Product is not identified as a fuel additive in the product materials reviewed. Its intended uses—lubrication, penetration, moisture displacement and corrosion protection—are different from the job of fuel or engine oil. The product description is not a direct manufacturer instruction about every possible gasoline mixture, but it provides no basis for using WD-40 as fuel treatment.
WD-40 Company says the Multi-Use Product contains petroleum distillates. That composition fact does not show that the product is suitable for combustion in an engine, safe at any concentration, or beneficial when mixed with gasoline. There is no established safe amount or universal dilution for this use.
What happens if WD-40 gets in gasoline?
The outcome depends on the engine, the amount involved and its fuel system. The available manufacturer guidance does not establish a single mechanical effect or a contamination threshold that predicts damage for every engine. It would therefore be misleading to promise that a small amount is harmless—or to claim that any amount will necessarily ruin an engine.
#1 Best Overall
- The only all-in-one carburetor cleaner spray you will need to clean your carburetor, throttle body, and unpainted metal parts
- Dual-action cleaning system 1. Solvent cleaning formula breaks up tough, baked on carbon deposits. 2. Powerful cleaning spray blasts away the deposits and waste
- Results are engines that start up fast and easy, and levels to a smooth, consistent idle with less stalling
- Use on old and new vehicles and equipment including; cars, trucks, tractors, motorcycles, boats, lawn mowers, weed trimmers, and all other gas powered lawn equipment
- Improve performance at high rpms. Will not affect oxygen (O2) sensors or catalytic converters upon incidental contact
WD-40’s U.S. Safety Data Sheet for the Low Odor aerosol, prepared November 13, 2024, classifies that specific product variant as an extremely flammable aerosol and lists aspiration toxicity and nervous-system effects after single exposure. Those are handling hazards; they do not establish what a particular quantity will do inside an engine. Follow the product label and SDS for safe handling, including keeping the product away from ignition sources and using it outdoors or with good ventilation.
WD-40 is not two-stroke premix oil
Some two-cycle (two-stroke) engines require gasoline mixed with purpose-made two-stroke oil. That is a manufacturer-specified fuel preparation, not a reason to add WD-40. Use only the oil type and fuel-to-oil ratio specified for the exact equipment.
Rank #2
- DESIGNED TO EXCEED EXPECTATIONS: Red Line complete SI-1 fuel system cleaner treatment for cleaning and preventing corrosion in fuel systems
- PERFORM AND PROTECT: Fuel additive cleans injectors, carburetors, valve and combustion chamber deposits with a powerful, concentrated blend of high-temp and low-temp detergents
- EFFICIENT FUEL BURN: Gas treatment that enhances gasoline stability, while reducing the build up of gum and varnish formation
- EASY TO USE: Use one bottle per tank for most effective treatment, additive cleans nearly 100% efficiency in one treatment
- 15 Ounce (2 Pack)
How requirements vary by engine
- Two-cycle engines: MTD/Cub Cadet says to use oil labeled for two-cycle or two-stroke engines, check the operator’s manual for the correct ratio, and not mix fuel and oil directly in the equipment tank. Its guidance states, “Always refer to the product engine Operator’s Manual for the correct ratio for that engine.” MTD/Cub Cadet guidance on mixing gasoline and oil.
- A model-specific example: The STIHL FS 85 / FS 85 R manual specifies gasoline mixed with STIHL two-stroke oil or a qualifying high-performance oil, and gives a 50:1 example for the covered models. It warns that unsuitable fuels or lubricants, or ratios other than those specified, may cause serious engine damage. That ratio and warning apply to those models and specifications; they are not a universal rule for two-stroke engines. STIHL FS 85 / FS 85 R manual.
- Four-cycle engines: These generally have separate fuel and oil systems, unlike two-cycle engines that use premix. Briggs & Stratton explains that using the wrong fuel or filling system can damage an engine or fuel system. Consult the equipment’s manual rather than adding oil or another product to the gas tank. Briggs & Stratton guidance on two-cycle and four-cycle engines.
Check the fuel specification for your exact equipment
Fuel rules differ by engine and model. Honda says its engines are designed for regular unleaded gasoline with 0–10% ethanol, but directs owners to the relevant manual for recommended fuel and currently approved additives. That guidance should not be generalized to equipment from other manufacturers or treated as approval to add WD-40. Honda Engines fuel recommendations.
Before fueling or preparing premix, check the manual for the required gasoline, any ethanol limit, whether the engine uses premix, the approved two-stroke oil and ratio, and any fuel-age or storage limits. Honda’s recommendation is to consult the owner’s manual for the applicable fuel and approved additives; an additive being approved for one model does not make it approved for another.
Rank #3
- The only all-in-one carburetor cleaner spray you will need to clean your carburetor, throttle body, and unpainted metal parts
- Dual-action cleaning system 1. Solvent cleaning formula breaks up tough, baked on carbon deposits. 2. Powerful cleaning spray blasts away the deposits and waste
- Results are engines that start up fast and easy, and levels to a smooth, consistent idle with less stalling
- Use on old and new vehicles and equipment including; cars, trucks, tractors, motorcycles, boats, lawn mowers, weed trimmers, and all other gas powered lawn equipment
- Improve performance at high rpms. Will not affect oxygen (O2) sensors or catalytic converters upon incidental contact
What to do if WD-40 has already gone into the fuel
- Do not start the engine or keep it running. Avoid testing whether it will run; the right response depends on the equipment and amount.
- Identify the equipment and contamination. Note the make and model, whether it is a two-cycle or four-cycle engine if known, how much WD-40 was added, how much fuel was in the tank, and whether the engine has been started.
- Check the operator’s manual and contact the manufacturer or a qualified repair professional. Ask for model-specific advice before draining, flushing or adding anything else.
- Follow product safety directions if there was exposure. For contact, inhalation or ingestion, consult the relevant product label and SDS. The WD-40 U.S. Low Odor aerosol SDS says not to induce vomiting if swallowed and to contact a poison center or physician immediately.
There is no universal cleanup procedure established for every engine and contamination amount. Don’t assume that draining the tank, flushing a line, adding more oil or diluting the fuel is the correct remedy; get advice for the specific situation.
Quick Recap
Best Value
- Powerful degreaser removes oil, dirt, grime, and grease from machinery and all types of engines
- Low-residue, water- based foaming formula penetrates deep into crevices for completely clean results
- Recommended application areas include auto and truck engines, industrial machinery, and farm equipment
- Nozzle sprays degreaser up to 5 ft. for long-distance application. It sticks to whatever you spray it on. Included straw creates a precision stream of cleaner for controlled application
- In independent laboratory testing, WD-40 Specialist Machine & Engine Degreaser Foaming Spray outperforms the leading competitors
Rank #4
- DESIGNED TO EXCEED EXPECTATIONS: Red Line complete SI-1 fuel system cleaner is a premium fuel additive, providing an effective fuel treatment solution to clean and prevent corrosion in fuel systems.
- PERFORM AND PROTECT: Fuel additive cleans injectors, carburetors, valve and combustion chamber deposits with a powerful, concentrated blend of high-temp and low-temp detergents
- EFFICIENT FUEL BURN: A gas treatment that enhances gasoline stability, while reducing the build up of gum and varnish formation, leading to smoother operation and increased power output.
- EASY TO USE: Use one bottle of Redline Fuel System Cleaner per tank for most effective treatment, additive cleans nearly 100% efficiency in one treatment
- ENAHNCED ENGINE EFFCIENCY: Experience improved fuel economy and engine performance with Red Line 60103 SI-1 Complete Fuel System Cleaner, as it effectively removes deposits, for enhanced exhaust system function
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
