Can I put 85 in my Subaru?

No. For most Subaru models, 85-octane gasoline or E85 is not recommended or supported. Use the fuel grade and ethanol content specified in your owner’s manual.

Here’s a detailed look at how octane ratings and ethanol blends relate to Subaru engines, plus practical guidance on what to use and what to avoid.

Octane requirements by Subaru model

Octane rating measures a fuel’s resistance to knocking. Using too low an octane can cause knocking, reduced performance, and potential engine damage—especially in turbocharged engines. Subaru generally allows regular 87-octane fuel for most vehicles, while turbocharged or high-performance models require higher-octane premium fuel as specified in the manual. Always confirm the exact requirement for your year and model.

Before the list: Key guidelines you should follow when choosing fuel for Subaru vehicles apply across most markets and model lines.

• Most non-turbo Subaru models are designed to run reliably on regular unleaded gasoline (87 octane) or higher as recommended by the manual.


• Turbocharged Subaru models (for example, WRX variants) typically require higher-octane premium fuel; using lower octane can trigger knocking and reduce performance.


• In some regions, the manual may mention alternative octane levels; always follow the exact spec printed for your specific vehicle and market.

Conclusion: 85 octane is below the minimum for most Subarus, and using it can lead to knocking, loss of power, and potential warranty considerations.

Ethanol fuel compatibility

Many Subaru engines tolerate ethanol blends up to a certain level. The common guidance for Subarus sold in the United States is fuel containing up to 10% ethanol (E10). Higher ethanol blends, such as E15 or E85, are generally not approved unless the vehicle is explicitly labeled as flex-fuel. Subarus are not marketed as flex-fuel vehicles in the U.S., and E85 is not a standard option for most models.

Before the list: The following points summarize ethanol-content guidance for Subaru owners.

• Fuel containing up to 10% ethanol (E10) is widely accepted in most Subaru models sold in the U.S. and many other markets.


• Ethanol blends greater than E10 (like E15 or E85) are typically not approved for non-flex-fuel Subarus; check your owner’s manual and the fuel-filler door label.


• Don’t assume a station’s label means your car is compatible; verify the vehicle’s official specification for ethanol tolerance.


• Using higher-ethanol fuels can affect fuel-system components and engine performance, and may impact warranty terms if not approved.

Conclusion: If your vehicle is not a flex-fuel model, stick with E10 or the ethanol content specified by Subaru for your region.

What to do if you accidentally fuel with 85

Immediate steps

If you’ve accidentally filled with 85-octane gasoline or E85 in a Subaru that isn’t flex-fuel, take prompt, careful actions to minimize risk to the engine and fuel system.

• Do not drive aggressively or put heavy load on the engine. If you can, refill with the correct fuel as soon as possible and avoid high-RPM operation until you’re sure the engine is running normally.


• If you’ve already started the vehicle, minimize driving and head to a service station to refuel with the proper fuel and have the system checked if you notice knocking, pinging, or performance issues.


• If you suspect you’ve put E85 into a non-flex Subaru, do not start the engine if it’s empty enough to drain; consult a mechanic for proper fuel draining and flushing guidance.

Conclusion: Quick corrective action reduces the risk of engine knock, fuel-system damage, or warranty issues. When in doubt, contact your Subaru dealer or a qualified technician for guidance.

Summary

Bottom line: For the vast majority of Subaru models, avoid 85-octane gasoline and absolutely do not use E85 unless the vehicle is explicitly advertised as flex-fuel and the owner’s manual confirms compatibility. Always follow the octane and ethanol-content specifications in your exact model’s manual and label. If you’re unsure, consult your dealer or service professional for model-specific guidance.

Is it okay to put 85 gas in my car?

It is not recommended that you use 85-rated fuel if you drive a modern car. You should use the rating recommended by your manufacturer, which can be found in your owner's manual.

What happens if I put E85 in a regular car?

Putting E85 in a regular car will likely cause the check engine light to come on and lead to performance issues like rough idling, hard starting, and a lean running condition, as the engine is not designed to handle the high ethanol content. In the long term, the corrosive nature of E85 can damage fuel system components like hoses, seals, and injectors, though a one-time mistake might not cause lasting harm if the fuel is consumed quickly or the tank is drained and flushed. 
Short-term effects

• Check Engine Light: The vehicle's computer will detect an issue, and the check engine light will likely illuminate. 
• Poor Performance: You may experience hard starting, rough engine operation, and stalling because the engine computer cannot adjust for the fuel's different properties. 
• Lean Condition: The engine will run "lean," meaning it's getting too much air relative to the fuel, which can lead to engine damage over time. 

Long-term effects

• Corrosion: Ethanol is highly corrosive and can degrade or corrode fuel system components not made to withstand it, such as seals, hoses, and plastic parts. 
• Component Damage: Repeatedly using E85 can lead to premature wear and failure of fuel injectors, pumps, and other parts. 
• Water Absorption: Ethanol is a solvent that attracts and holds water, which can lead to corrosion in the fuel tank, especially with older, steel tanks. 
• Voided Warranty: Using a fuel that your car isn't designed for can void your manufacturer's warranty. 

What to do if you made a mistake

• Do not drive if possible: If you notice poor performance or the engine runs poorly, it's best to have the vehicle towed to a mechanic. 
• Drain the tank: A mechanic can drain the E85 from the tank and replace the fuel filter. 
• Refill with gasoline: Once the tank is flushed, refill it with the correct, regular gasoline for your vehicle. 

Can a Subaru take 85 gas?

Here's what you need to know about using these fuel types for your Subaru: E10 (10% ethanol): It's safe for all Subaru models. E15 (15% ethanol): It's not recommended because of potential engine wear. E85 (85% ethanol/flex fuel): There are no Subaru flex-fuel vehicles, so you shouldn't use E85.

What happens if I use 85 octane instead of 87?

Using 85 octane instead of 87 in a modern car is likely to result in a performance decrease, including power loss and reduced fuel economy, because 85 octane is less resistant to pre-ignition or detonation. Modern engines have advanced management systems that detect the lower octane and adjust to prevent engine knock, but this can negatively impact efficiency and acceleration. Damage is less likely but still possible, especially for engines with turbochargers or when driving at lower elevations or under heavy load. 
Potential problems

• Engine knock/pinging: Lower octane fuel can self-ignite prematurely, causing a knocking or pinging sound. 
• Reduced power: The engine's computer will adjust settings to prevent knocking, which often results in a loss of power and slower acceleration. 
• Lower fuel economy: The adjustments made by the engine's control system to avoid knocking can lead to less efficient combustion, reducing your miles per gallon. 
• Potential for damage: While modern engines are designed to prevent damage, using lower-octane fuel than recommended, especially in turbocharged or high-compression engines, can cause serious engine damage over time. 
• Warranty void: Using a lower octane fuel than recommended by the manufacturer could potentially void your engine's warranty if engine damage occurs as a result. 

What to do

• Follow the manufacturer's recommendation: The best practice is to always use the octane rating specified in your owner's manual or on the sticker inside the fuel filler door. 
• Use 87 octane or higher: If your car recommends 87 octane, use at least that amount to avoid potential issues. 
• Consult your manual: If you are unsure, check your owner's manual. It will tell you the manufacturer's minimum octane requirement.