Skip to content 
Starting fluid is a cold-weather tool, not a cure-all. Before reaching for a can, there are a few things worth knowing.
Ether, the active ingredient in most starting fluids, is a powerful solvent. Without lubricity additives, it strips the oil film off cylinder walls and accelerates wear. Look for products labeled “Upper Cylinder Lubricant” rather than grabbing whatever is cheapest. Cheap cans often have low ether content anyway, making them largely pointless.
Compatibility is the bigger concern. Direct injection diesels are generally built with ether use in mind. Indirect injection (IDI) engines are not, and many carry warning labels explicitly prohibiting it. If you are unsure which you have, check before you spray.
The hardest rule: never use ether in an engine with active glow plugs or an intake grid heater. The fluid can detonate in the intake manifold and cause serious mechanical damage.
If your engine falls into any of those restricted categories, propane or silicone spray are gentler alternatives worth considering.
Starting fluid works well in the right situation. The right situation means a compatible engine, the correct product, and a battery strong enough to crank the engine past 200 rpm. If any of those conditions are missing, the fluid will not save you.
STA-BIL Starting Fluid
STA-BIL Starting Fluid
Sta-Bil starting fluid is for gas and diesel engines struggling to fire in extreme cold or after extended storage.
Temperature rating: -65°F
Ether content: 40-60% diethyl ether
Shelf life: 2 years after opening
Additives: Upper cylinder lubricant, corrosion inhibitors
Sta-Bil contains upper cylinder lubricant to protect engines. Ether is a solvent that strips the oil film off cylinder walls during a cold start. Most budget cans skip this additive entirely.
STA-BIL also lists compatibility with oxygen sensors and catalytic converters, which matters for anyone using it on modern engines. This suits operators who need one product that works across multiple equipment types, or who want something stored in an emergency kit that will still be viable two seasons from now.
Spray directly into the carburetor, air cleaner, or intake for a few seconds before cranking. If your diesel has glow plugs or a preheat manifold, check the manufacturer’s directions before use.
Compatible with: cars and trucks, motorcycles, snowmobiles, lawnmowers, snow blowers, tractors, construction equipment, outboard and marine engines.
Valvoline Extra Strength Starting Fluid
Valvoline Starting Fluid with Upper Cylinder Lubricant
Valvoline Extra Strength is for gas and diesel engines struggling to fire in extreme cold or after extended storage.
Ether content: 20-30% ethyl ether Heptane content: 50-70% Propellant: Carbon dioxide Flash point: -49°F Additives: Upper cylinder lubricant Product code: 602373
Heptane makes up the bulk of this formula, which gives it a low freezing point and high vapor pressure. That combination allows it to vaporize quickly and pass through air filters to reach the combustion chamber. Ether concentration is moderate compared to high-ether alternatives like Lucas Sure Start, but the formula also includes ethanol and ethyl chloride, which contribute to cold ignition. It meets federal low-sulfur requirements for diesel use.
This suits operators running mixed equipment who want a single product that handles both gas and diesel applications.
Spray directly into the carburetor or air intake before cranking. Store away from heat and open flame and do not expose the can to temperatures above 122°F.
Compatible with: cars and trucks, diesel engines, lawnmowers, chainsaws, outboard motors, fractional horsepower engines
Johnsen’s Starting Fluid
Johnsen’s 6732 Premium Starting Fluid
Johnsen’s is for gas and diesel engines struggling to fire in extreme cold or after extended storage. Available in two concentrations: 50% ether and 20% ether.
Temperature rating: -65°F Ether content: 45-50% diethyl ether (50% blend) Propellants: Liquefied petroleum gas, carbon dioxide Flash point: -75°F Additives: Upper cylinder lubricant VOC content: 93.3%
The 50% ether blend puts Johnsen’s in the same range as Lucas Sure Start for cold-weather performance. The flash point of -75°F is among the lowest of any starting fluid, meaning it vaporizes readily even in serious cold. It meets federal low-sulfur requirements for diesel use.
If you run lighter equipment or are concerned about ether concentration, the 20% blend is available as a gentler option for less demanding situations.
Spray directly into the carburetor or air intake before cranking.
Compatible with: cars and light trucks, heavy-duty diesel engines, lawnmowers, chainsaws, fractional horsepower engines, outboard motors
B’laster Starting Fluid
B’laster Starting Fluid, a Fast-Acting Gasoline and Diesel Starting Fluid
B’laster is for gas and diesel engines struggling to fire in extreme cold or difficult weather conditions.
Ether content: 15-30% diethyl ether Heptane content: 70-85% Propellant: Carbon dioxide Flash point: -45°F Size: 11 oz
Heptane is the dominant ingredient here, making up as much as 85% of the formula. Ether concentration is on the lower end compared to alternatives like Lucas Sure Start or Johnsen’s 50% blend. The datasheet does not list an upper cylinder lubricant, which is worth noting. Ether strips the oil film off cylinder walls during a cold start, and without a lubricity additive that wear adds up over repeated use.
This suits operators who need a basic, widely available starting aid for occasional use rather than a go-to for extreme cold or high-demand situations.
Spray directly into the carburetor or air intake before cranking. Do not expose the can to temperatures above 122°F.
Compatible with: cars, lawnmowers, gasoline and diesel engines
Different Types of Starting Fluids
Starting fluids are not all built the same, and the differences matter more than most operators realize.
Ether-Based Starting Fluids
Ether is the standard active ingredient because it ignites at a very low temperature and vaporizes quickly. That volatility is also what makes it hard on engines. Pure ether is a powerful solvent that strips the oil film off cylinder walls, which over time leads to scoring and ring damage. Premium fluids like CRC Jump Start include upper cylinder lubricants specifically to counter this. If you are using ether regularly, that additive is worth paying for.
Concentration varies significantly between brands. Professional-grade fluids tend to be noticeably more potent than cheap alternatives. Some dollar-store cans have very low ether content or are propane-based entirely, which makes them largely pointless in a genuine cold-start situation.
Petroleum-Based Aerosols
Common workshop sprays are often used as gentler alternatives to straight ether. WD-40 was traditionally popular because it is kerosene-based, but its effectiveness has changed. Older formulations used propane as a propellant, which aided ignition. Modern cans use CO2, which is non-flammable and contributes nothing to combustion.
Silicone spray is a better alternative for operators concerned about engine wear. It ignites well enough to aid starting while also lubricating, which reduces the knocking associated with ether. Carburetor cleaner and penetrating fluids like PB Blaster are also used in the field as less volatile substitutes.
Gaseous and Vaporized Fuels
Gaseous fuels work differently from aerosols. Rather than a liquid solvent hitting cold cylinder walls, they introduce fuel in a vaporized state that a cold engine can ignite more easily.
Propane is the most common method. An unlit torch held near the air intake lets the engine draw in gas as it cranks. It is less volatile than ether and considered less likely to cause ring damage. A gasoline-soaked rag held over the intake works on the same principle, allowing the engine to draw vapors rather than liquid. Some operators also use a fine pump sprayer to mist diesel directly into the intake once the engine has begun firing, helping it pull through fuel system air locks.
What Not to Use
CRITICAL: Never use brake cleaner as a starting fluid. It will cause catastrophic engine damage.
Beyond specific products, volume is its own hazard. Regardless of what fluid you use, excess fluid in the intake can hydro-lock the engine, blow head gaskets, or shatter piston rings. Use the minimum amount necessary, always.
WD-40 as a Starting Fluid
WD-40 is a common alternative to ether-based starting fluids, often described as a gentler option. It is primarily kerosene-based, which is combustible enough to help a cold engine fire.
The catch is that its effectiveness has changed. Older cans used propane as a propellant, which is highly flammable and did most of the work. Modern cans use CO2, which is non-flammable and contributes nothing to combustion. If you are reaching for a can of WD-40 today, it is likely less effective than what mechanics were using ten or twenty years ago.
Where it still has an edge over ether is in how it behaves in the cylinder. Ether ignites violently and can cause knocking that pounds bearings and bends rods. WD-40 is less volatile and provides some lubrication as it burns, which is easier on engine internals. That said, in extreme cold it may not have enough volatility to fire a truly cold-soaked engine.
Spray into the intake manifold or throttle body rather than through the airbox. Fluid pooling in the airbox can cause backfires. Use sparingly regardless, as excess fluid of any kind risks hydro-locking the engine or breaking piston rings.
If WD-40 is unavailable, silicone spray is a better alternative. It ignites reliably and provides more lubrication than most modern aerosols.
CRITICAL: Never use any starting fluid on engines equipped with active glow plugs or intake grid heaters. Vapors contacting those heated elements can detonate in the intake manifold.
If you are reaching for a starting aid regularly, the engine likely has an underlying issue worth diagnosing first.
Closing Notes
Starting fluid is a cold-weather tool, not a maintenance plan. If your engine needs it regularly, that is a symptom worth investigating rather than working around.
On diesels, frequent use can mask wet stacking, a condition where unburnt fuel carbonizes and glazes cylinder walls over time. Low-quality fuel with a poor cetane rating raises the auto-ignition temperature, which makes cold starts harder and increases dependence on starting aids. That is worth checking before reaching for a bigger can.
Ether also acts as a refrigerant as it evaporates. Over-spraying can cold-shock metal components and cause hairline fractures in piston crowns. Use the minimum amount necessary, every time.
Store cans upright in a temperature-controlled environment. Extreme heat degrades the internal seals and can cause hazardous leaks.
A healthy engine should start unaided above 32°F. If yours does not, a compression test will tell you more than any starting fluid will.
