Starting Fluid

What Is Starting Fluid and Why Does It Matter?

Starting fluid is a highly volatile liquid designed to help start internal combustion engines, especially under challenging conditions such as extreme cold or mechanical issues. Typically packaged in aerosol cans, it contains ether — a substance known for its high combustibility and rapid ignition properties. It belongs in every serious mechanic's toolbox and is a must-have for anyone who operates vehicles or equipment in cold climates.

When you spray starting fluid into the engine's air intake or carburetor, it quickly vaporizes and mixes with the incoming air, creating a highly combustible air-fuel mixture that is much easier to ignite than regular gasoline or diesel fuel. This product is most often used when an engine is cold-soaked during winter conditions, or when an engine has been sitting unused for a long period, causing mechanical difficulty in achieving initial combustion. By introducing a highly reactive fuel source directly into the intake air stream, the fluid overcomes common starting hurdles like low ambient temperatures or poor compression — temporarily aiding the engine into running on its primary fuel supply while reducing wear on the starter and battery during prolonged cranking.

How to Use Starting Fluid Safely

Most starting fluid comes in spray cans and can be used in very small amounts to make an engine start when it's extremely cold out, or if there is a problem with the ignition system that is keeping the engine from firing. Because it is highly explosive, you should only use a very small amount — spray it directly into the air intake. Using too much can damage your engine, as the force from igniting an excessive amount can cause serious damage, such as cracked piston heads and bent piston rods.

Mechanics also use it to diagnose starting problems by determining whether the spark and ignition system of the vehicle is functioning — if the spark is adequate but the fuel delivery system is not, the engine will run until the starting fluid vapors are consumed. Caution is required when using starting fluid with diesel engines that have preheat systems in the intake or glow plugs installed, as the starting fluid may pre-ignite, leading to engine damage.

What to Look For When Buying Starting Fluid

• Ether concentration: The active ingredient is nearly always diethyl ether, which typically constitutes a significant portion of the fluid — often ranging from 30 to 60 percent in premium-grade formulations — providing the necessary volatility to initiate combustion.
• Upper cylinder lubricant: Many formulations include small amounts of petroleum distillates or heptane, which help lubricate the upper cylinder walls upon ignition, since ether itself offers no lubricity.
• Temperature rating: Look for products rated to at least -65°F for reliable performance in extreme cold.
• Engine compatibility: Confirm the product is safe for your engine type — gasoline, diesel, or small engines like chainsaws and lawn mowers.

Top Starting Fluid Brands

Lucas Oil is one of the most trusted names in automotive additives, and their Sure Start line carries that reputation directly into starting fluids. Lucas Sure Start Premium Starting Fluid features a 50% ether blend that goes beyond other leading national brands by also including an effective lubricant, making it an ideal starting fluid for starting sluggish motors and limiting the impact of extreme cold weather on vehicle batteries. It is formulated for use in passenger cars, diesel engines, lawn mowers, chain saws, outboard motors, and fractional horsepower engines.

CRC Industries brings decades of specialty chemical expertise to the starting fluid category. CRC is a worldwide leader in the production of specialty chemicals for the maintenance and repair professional, serving industrial, electrical, aviation, automotive, and marine markets. CRC Jump Start® is effective and safe to apply in a variety of weather conditions, including extreme cold or humidity, quickly and economically restarting your engine in freezing temperatures as low as -65 degrees Fahrenheit, and is enhanced with an upper cylinder lubricant to further minimize engine damage during cold starts.

Golden Eagle Manufacturing rounds out the lineup with a focused selection of starting fluid products trusted by professionals and DIYers alike. Gunk is a long-standing name in automotive chemicals known for dependable, no-frills solutions that get the job done under the hood.