What Happens If You Accidentally Put 87 Instead of 91 in Mercedes?

Hey Mercedes folks! Imagine you pull up to the gas station, preoccupied with your busy day ahead, and without realizing it, you accidentally choose 87 octane fuel instead of the prescribed 91!

So, What Happens If You Accidentally Put 87 Instead of 91 in Mercedes? Now, before you start to panic, you need to know it’s not a big problem what you think. Look, this change will not do any damage to your car for a short time. Your car won’t immediately crumble into a heap of metal, but it’s definitely not ideal for a long time. Because continuously doing it will cause reduced performance, lower fuel economy, and sluggish acceleration.

However, I should warn you that running on low-octane fuel for an extended period can inflict severe damage on your engine. So, let’s know why. Keep on reading this article, and I’m gonna clear up everything.

What Happens If You Accidentally Put 87 Instead of 91 in Mercedes?

Nothing significant if you accidentally put 87 instead of 91 in Mercedes. But make sure you won’t do this next time. Doing so can cause serious harm to your favorite Mercedes.

So, Can You Put 87 in A Mercedes?

I won’t say yes. Here’s what happens if you accidentally put 87 octane gas instead of 91 in a Mercedes requiring premium fuel:

• The engine may knock or ping due to premature fuel ignition. This can damage internal components over time.
• Performance will be reduced. The engine management system will retard timing to compensate for the lower octane, resulting in less power.
• The fuel economy may suffer slightly since ignition timing can’t operate at maximum efficiency.
• Long-term issues like buildup on valves and spark plugs are possible if run extensively on 87 octane.
• The “check engine” light may activate and set fuel-related error codes due to abnormal combustion.
• The best remedy is to refuel with 91 octane premium fuel as soon as possible. Avoid prolonged high-load driving until the tank is refilled. Using a higher grade one tankful won’t undo long-term lower octane use but can help restore proper operation. Check for ongoing issues if performance problems or warning lights persist.

Difference Between 87 And 91 Octane Fuel – Table

Octane Rating	87 Octane	91 Octane
Research Octane Number (RON)	87	91
Motor Octane Number (MON)	82	87
Anti-Knock Index (AKI)	87	91
Ignition Timing	Advanced ignition timing required	Standard ignition timing
Performance	Reduced performance, lower power output, sluggish acceleration	Optimal performance, higher power output, smoother acceleration
Fuel Economy	Slightly lower fuel efficiency, increased fuel consumption	Improved fuel efficiency, reduced fuel consumption
Engine Knock	Increased likelihood of spark knock, high-pitched rattling noise	Minimal risk of engine knock, smoother engine operation
Engine Protection	Lesser protection against knocking and engine damage	Enhanced protection against knocking and engine damage
Compatibility	Suitable for most standard vehicles, including non-performance cars	Recommended for high-performance and luxury vehicles, including Mercedes-Benz
Cost	Generally lower cost per gallon compared to higher octane fuels	Slightly higher cost per gallon compared to lower octane fuels
Turbocharged Engines	May experience more turbo lag	Reduced turbo lag
Emissions	Potential for slightly higher emissions	Potential for slightly lower emissions
Energy Content	Lower energy content per gallon	Higher energy content per gallon
Flame Propagation	Slower flame propagation	Faster flame propagation
Detonation Resistance	Lower detonation resistance	Higher detonation resistance
Engine Efficiency	Slightly reduced engine efficiency	Improved engine efficienc

Related Readings: Using Octane Booster Instead Of Premium Gas

What If I Accidentally Put Regular Gas in Mercedes?

Here’s what happens if you accidentally put regular gas in a Mercedes requiring premium fuel:

• You may hear knocking or pinging as the engine combusts the fuel prematurely. This can eventually cause internal damage over time.
• Performance will decrease as the engine computer retards ignition timing to compensate for the lower octane fuel. Less power and acceleration.
• Fuel economy may drop slightly since the engine can’t run at maximum efficiency with regular gas.
• Carbon buildup on valves and spark plugs is possible if driven extensively on regular fuel.
• The check engine light may turn on due to abnormal combustion. Fuel-related error codes may be stored.

The best fix is to refill the tank with premium fuel as soon as you can. Avoid heavy acceleration or hauling heavy loads until then. Topping off with higher octane gasoline can help restore proper performance but doesn’t undo any long-term issues from prolonged regular gas use.

Impact of Using 87 Octane Fuel In Mercedes

When it comes to Mercedes-Benz cars, which are designed to run on premium fuel, using 87-octane fuel can have noticeable effects on various aspects of your vehicle’s performance.

Let’s delve into the details to understand the impact:

How Mercedes-Benz Cars Adjust to Lower Octane Fuel

Mercedes-Benz vehicles are equipped with advanced engine management systems that can adapt to lower-octane fuel.

These systems make adjustments to the engine’s timing and combustion parameters to compensate for the lower quality fuel.

While these adaptations prevent immediate damage, it’s important to note that running on lower octane fuel is not ideal for the long-term health of your Mercedes.

Effects on Performance, Fuel Economy, and Acceleration

Using 87-octane fuel in a Mercedes can lead to a reduction in overall performance. You may experience decreased power output, slower acceleration, and a general sense of sluggishness.

Additionally, fuel economy may suffer, as the lower octane fuel is less efficient in terms of energy conversion.

It’s not uncommon to see increased fuel consumption when running on 87 octane fuel.

Spark Knock: What It Is and How It Relates to Using Lower Octane Fuel

One of the most significant concerns when using lower octane fuel is the occurrence of spark knock, also known as engine knocking or pinging.

Spark knock is an abnormal combustion process characterized by a high-pitched rattling or knocking noise.

It is caused by the fuel-air mixture in the combustion chamber igniting prematurely or unevenly.

Lower octane fuel is more prone to spark knock because it has a lower resistance to self-ignition.

Related Reads:

• Can I use 86 octane instead of 87
• Can I Use 93 Octane Instead Of 91
• Can I Use 92 Octane Instead Of 93

The Importance of Refilling with 91 Octane Fuel

Here I mention some points to make you aware about importance of refilling with 91 octane fuel in your Mercedes-Benz –

The Role of Octane Rating in Engine Combustion and Performance

Octane rating plays a vital role in the combustion process of your Mercedes-Benz engine. The octane number indicates the fuel’s ability to resist spontaneous combustion under pressure.

Higher octane fuel has a greater resistance to premature detonation, allowing for more controlled and efficient combustion. This leads to smoother engine operation, improved power delivery, and overall better performance.

Why Refilling with the Correct Fuel Grade is Crucial

Refilling your Mercedes with the correct fuel grade, specifically 91 octane, is crucial to ensure optimal engine performance and longevity.

The engine’s design and calibration are based on the assumption of using the recommended fuel, including the timing of fuel injection, ignition, and other parameters.

By using the appropriate octane rating, you provide the engine with the optimal conditions for combustion, maintaining efficiency, power output, and minimizing the risk of damage.

Using the Proper Octane Rating Restores Performance

When you refill your Mercedes with 91 octane fuel, the engine management system adjusts the engine’s parameters accordingly.

The precise timing of fuel injection and ignition is restored, allowing for proper combustion and performance.

As the engine adapts to the higher octane fuel, you should notice a return to the vehicle’s intended power output, improved acceleration, and smoother operation.

Tips for Preventing Fueling Mistakes

To prevent the costly and potentially damaging mistake of accidentally using the wrong octane fuel in your Mercedes, here are some valuable tips and precautions to follow:

• Double-Check Fuel Grades: Before inserting the fuel nozzle into your vehicle, take a moment to double-check the fuel grade displayed on the pump. Look for the octane rating recommended by the manufacturer, which in the case of Mercedes-Benz, is typically 91 octane. Ensure that you have selected the correct fuel grade to avoid any mix-ups.
• Use Reminders: If you find yourself frequently forgetting the recommended octane rating for your Mercedes, consider using reminders.
• You can set a reminder on your smartphone or place a small note near your fuel cap as a visual cue. This simple practice can help reinforce the importance of using the right fuel and serve as a helpful memory aid.
• Be Attentive During Refueling: When refueling your vehicle, it’s essential to be attentive and focused on the task at hand. Avoid distractions and take your time to ensure that you select the correct fuel grade and insert the nozzle into the appropriate fuel tank. Rushing or being distracted increases the chances of making a fueling mistake.
• Know Your Vehicle’s Requirements: Familiarize yourself with your Mercedes-Benz model’s specific fuel requirements. Consult the owner’s manual or contact the manufacturer for information on the recommended octane rating and any additional fuel-related guidelines. Being knowledgeable about your vehicle’s needs helps you make informed decisions when refueling.
• Ask for Assistance, if Needed: If you’re uncertain about the proper fuel grade for your Mercedes or have any doubts while refueling, don’t hesitate to ask for assistance.

Gas station attendants or knowledgeable staff can guide you and provide clarity regarding fuel options, ensuring you make the right choice.

Related Read: Can You Clean Fuel Injectors Instead Of Replacing Them

FAQ’s

Final Words

So, if you accidentally put 87 instead of 91 in mercedes, it’s crucial to address the situation promptly. Continuing to run on 87 octane fuel for an extended period can potentially cause serious damage to the engine.

To mitigate the risk factors, it’s recommended to refill your tank with the appropriate 91 octane fuel as soon as possible.