Your Mercedes-Benz CLS Class demands premium care. For its engine to perform flawlessly, regular oil changes are essential. This guide clarifies the precise CLS Class oil change interval, offering you peace of mind and helping you maintain your luxury sedan’s peak condition. We’ll break down the factors influencing this interval and provide straightforward advice, ensuring your CLS Class runs smoothly mile after mile.

Welcome to MercedesBlue! I’m Bryan Bowman, and I’m thrilled to help you navigate the world of your Mercedes-Benz CLS Class. Owning a vehicle with such sophisticated engineering requires understanding its specific needs, and one of the most crucial is routine maintenance, particularly oil changes.

For many CLS Class owners, the question of “when is the right time for an oil change?” can be a source of confusion. The digital age has brought us advanced systems, but sometimes a good old-fashioned maintenance schedule is what keeps our magnificent machines purring.

This article isn’t just about a number; it’s about protecting your investment. We’ll demystify the CLS Class oil change interval, explaining what factors Mercedes-Benz considers and how you can easily track it. We’ll ensure you’re never left guessing, empowering you to keep your CLS Class in its best possible shape. Let’s dive into the details and give your CLS Class the attention it deserves.

Table of Contents

Understanding the CLS Class Oil Change Interval

The Mercedes-Benz CLS Class is engineered for performance and longevity, and its oil change schedule is meticulously designed to support these goals. Unlike older vehicles with fixed mileage intervals, modern Mercedes-Benz models, including the CLS Class, often utilize a more sophisticated system that takes into account how the vehicle is driven. This system is commonly referred to as “Assyst Plus” or a similar intelligent maintenance reminder system.

Factors Influencing Oil Change Frequency

Several key factors affect when your CLS Class will need an oil change:

Driving Style: Aggressive driving (frequent hard acceleration, braking, and high RPMs) puts more stress on the engine oil, leading to faster degradation. Conversely, gentle, consistent highway driving is less demanding.
Driving Conditions: Frequent short trips where the engine doesn’t reach optimal operating temperature, driving in extreme temperatures (very hot or very cold), or towing/hauling can also shorten the oil change interval.
Oil Quality: Using the correct viscosity and specification of synthetic oil recommended by Mercedes-Benz is paramount. Higher quality oils generally offer better protection and last longer.
Engine Technology: Modern engines and advanced synthetic oils are designed to withstand greater stress and last longer than older technologies.
Model Year and Specific CLS Variant: Different CLS generations and specific engine options within those generations might have slightly varied recommendations.

The Role of the ASSYST Maintenance System

Your CLS Class is equipped with an advanced onboard computer system, often called ASSYST (Active Service System) or similar, which monitors various vehicle parameters. This system doesn’t just rely on a fixed mileage or time interval; it calculates the remaining oil life based on your actual driving habits.

When you start your CLS Class, the instrument cluster will display a message indicating how much time or mileage is left until your next service is due. This message typically shows “Service A due in XXX days/miles” or “Service B due in XXX days/miles,” with oil changes being a primary component of these services.

This intelligent system ensures that your oil is changed when it’s actually needed, optimizing maintenance costs and protecting your engine effectively. It’s designed to adapt to your driving, providing a personalized maintenance schedule.

General Guidelines vs. System Recommendations

While the ASSYST system is the most accurate way to determine your oil change needs, it’s helpful to have general guidelines. Historically, Mercedes-Benz recommended oil changes between 10,000 and 15,000 miles or once a year, whichever comes first. However, with advancements in oil technology and engine management, these intervals can extend, especially for models with the active service system.

Crucially, always defer to the ASSYST system’s notification. It is calibrated specifically for your vehicle’s engine and the oil installed.

If you recently purchased a pre-owned CLS Class, it’s a good practice to check the service history. If records are unavailable or if you’re unsure when the last oil change was performed, it’s best to perform one proactively, especially if your car is approaching the general 10,000-mile mark or has been a year since its last documented service.

What Oil to Use for Your CLS Class

Choosing the correct engine oil is as vital as adhering to the correct oil change interval. Mercedes-Benz specifies particular oil specifications ensuring optimal performance and protection for your CLS Class engine. Using the wrong oil can lead to premature wear, void your warranty, and negatively impact fuel efficiency.

Mercedes-Benz Approved Oil Specifications

Mercedes-Benz assigns specific MB-Approval numbers to engine oils that meet their stringent quality and performance standards. These approvals ensure the oil has been rigorously tested in their engines. The specific MB-Approval number required can vary depending on your CLS Class model year and engine.

Common MB-Approval specifications you might encounter include:

MB 229.5: This is a widely used specification for gasoline engines, offering excellent wear protection and extended drain intervals.
MB 229.51: Often used for diesel engines and some gasoline engines, this specification is designed for vehicles equipped with diesel particulate filters (DPFs) and offers low SAPS (Sulphated Ash, Phosphorus, and Sulphur) content to protect emission systems.
MB 229.6: A specification for fuel-economy-optimized gasoline engines.
MB 229.71: A newer specification, often for the latest generation of engines, providing superior protection and compatibility with advanced emission systems.

Always consult your CLS Class owner’s manual or the ASSYST system’s display for the exact MB-Approval specification required for your vehicle. You can also find this information on the oil filler cap or by checking the Mercedes-Benz official lubricant finder (https://operatinginstructions.mercedes-benz.com/).

Why Synthetic Oil is Crucial

Your CLS Class engine requires a high-performance synthetic oil. Here’s why:

Superior Protection: Synthetic oils are engineered at a molecular level to provide better lubrication, withstand higher temperatures, and resist breakdown under stress compared to conventional oils. This is crucial for the high-performance engines found in the CLS Class.
Extended Intervals: High-quality synthetic oils maintain their properties for longer, allowing for the extended oil change intervals recommended by Mercedes-Benz.
Engine Cleanliness: Synthetics contain fewer impurities and often have superior additive packages that help keep the engine clean by preventing sludge and deposit formation.
Cold Weather Performance: Synthetic oils flow better at low temperatures, ensuring faster lubrication of engine components during cold starts, which is a critical factor in reducing engine wear.
Hot Weather Stability: They also offer better thermal stability at high operating temperatures, preventing oil thinning and maintaining protective film strength.

When purchasing oil, look for brands that clearly state they meet the required MB-Approval specification. Common reputable brands include Mobil 1, Castrol, Liqui Moly, and Valvoline, among others, that offer synthetic oils specifically formulated for Mercedes-Benz vehicles.

Oil Viscosity Grades

Viscosity refers to an oil’s thickness and its ability to flow. The most common viscosity grades for CLS Class vehicles are 0W-40 and 5W-40, but this can vary. The “W” stands for “Winter,” and the number before it indicates the oil’s viscosity at cold temperatures, while the second number indicates viscosity at operating temperature.

Example: 0W-40 oil flows more easily in cold weather than 5W-40 oil, while both offer similar protection at engine operating temperatures. The owner’s manual will specify the recommended viscosity grade, often with allowances for different ambient temperatures.

Performing a CLS Class Oil Change: DIY vs. Professional

Deciding whether to perform an oil change yourself or take it to a professional is a common consideration for CLS Class owners. Both options have their pros and cons, and the best choice often depends on your comfort level, available tools, and time.

Doing It Yourself (DIY)

A DIY oil change can be a rewarding experience, saving you money and giving you insight into your vehicle’s maintenance.

Tools and Supplies You’ll Need:

New Engine Oil: The correct type and quantity, meeting MB-Approval specifications. Your owner’s manual will specify the exact amount.
New Oil Filter: Ensure it’s a high-quality filter specifically designed for your CLS Class model.
Oil Filter Wrench: A specialized tool to remove and tighten the oil filter housing.
Wrench or Socket Set: To remove the oil drain plug.
Drain Pan: Large enough to hold all the old oil.
Funnel: For adding the new oil cleanly.
Rags or Shop Towels: For cleaning up spills.
Gloves: To keep your hands clean.
Jack and Jack Stands: If you need to lift the vehicle for access. Ensure they are rated for your vehicle’s weight and used on a level surface.
Torque Wrench: To ensure the drain plug is tightened to the manufacturer’s specification.
New Drain Plug Seal/Washer: Always recommended to replace.

Basic Steps for a DIY Oil Change:

Warm Up the Engine: Run the engine for a few minutes to warm the oil. Warm oil drains more easily.
Locate Drain Plug: Safely lift the front of the car if needed and locate the oil pan and its drain plug.
Position Drain Pan: Place the drain pan directly beneath the drain plug.
Remove Drain Plug: Carefully loosen and remove the drain plug using the appropriate wrench. Be prepared for the hot oil to flow out rapidly.
Drain the Oil: Let the oil drain completely (this can take 10-15 minutes).
Replace Drain Plug: Once drained, clean the drain plug and the area around the drain hole. Install a new seal/washer, and then reinstall the drain plug. Tighten it to the manufacturer’s specified torque using a torque wrench.
Locate and Remove Oil Filter: Find the oil filter housing. Use the oil filter wrench to unscrew it. Be aware that some oil will likely spill out.
Prepare New Oil Filter: Lightly coat the rubber gasket of the new oil filter with a bit of new oil. Fill the new filter with fresh oil about halfway if it’s a spin-on type, or as directed if it’s a cartridge type.
Install New Oil Filter: Screw the new oil filter on by hand until the gasket makes contact, then tighten an additional ¾ to 1 full turn (or as specified by the filter manufacturer).
Add New Oil: Lower the vehicle if it was raised. Open the hood and locate the oil filler cap. Using a funnel, add the specified amount of new engine oil.
Check Oil Level: Replace the oil filler cap. Start the engine and let it run for a few minutes. Check for any leaks under the car. Turn off the engine, wait a few minutes, and then check the oil level using the dipstick or the electronic oil level indicator in your instrument cluster. Add more oil if necessary, ensuring you don’t overfill.
Reset Service Indicator: You’ll need to reset the ASSYST system’s service reminder. The procedure varies by model year, but often involves a sequence of button presses on the steering wheel or dashboard. Consult your owner’s manual for the exact steps.

Professional Service

Taking your CLS Class to a qualified Mercedes-Benz dealership or a reputable independent specialist offers several advantages:

Expertise: Technicians are factory-trained and familiar with Mercedes-Benz vehicles and their specific needs.
Correct Parts: They use genuine Mercedes-Benz or equivalent approved parts and fluids.
Warranty Protection: Ensures your maintenance is performed correctly, maintaining warranty compliance.
Specialized Tools: Access to specialized diagnostic equipment and tools required for complex procedures or resets.
Peace of Mind: Knowing the job is done right by professionals.

While generally more expensive than DIY, professional servicing provides assurance that all aspects of the service are handled by experts, including proper diagnosis of any other potential issues. For a complex and luxurious vehicle like the CLS Class, many owners opt for professional service to ensure optimal care, especially when it comes to the intricacies of the ASSYST system reset and ensuring all specifications are met.

Understanding CLS Class Service Codes (A and B Service)

Mercedes-Benz uses a coded system for its scheduled maintenance to simplify the process for owners. The most common services are “Service A” and “Service B.” These codes indicate the scope of work required, with oil changes being a fundamental part of both.

Service A

Service A is the minor service and is typically the first service recommended for a new vehicle. It usually includes:

Mercedes-Benz Synthetic Motor Oil Replacement
Oil Filter Replacement
Tire Inflation Check and Adjustment
Tire Rotation
Inspection of Front and Rear Brakes for Thickness
Check and/or Replacement of Wiper Blades
Fluid Level Checks and Correction
Check of the vehicle’s exterior and interior lights
Check of dashboard warning lamps
Reset of the Service Reminder Indicator

Your ASSYST system will typically indicate “Service A due in X days/miles.”

Service B

Service B is the major service and follows Service A. It includes all the items from Service A, plus additional inspections and potential replacements. These often include:

Mercedes-Benz Synthetic Motor Oil Replacement
Oil Filter Replacement
Tire Inflation Check and Adjustment
Tire Rotation
Inspection of Front and Rear Brakes (pads, rotors, lines, calipers)
Replacement of Cabin Air Filter (dust filter)
Replacement of Engine Air Filter
Check of Wiper Blades, Fluid Level, and Operation
Inspection of the vehicle’s exterior and interior lights
Check of dashboard warning lamps
Check of various fluid levels (e.g., coolant, brake fluid, power steering fluid) and topping off as needed.
More comprehensive inspections, such as checking suspension components, exhaust system, and more.
Reset of the Service Reminder Indicator

Your ASSYST system will typically indicate “Service B due in X days/miles.” For example, a common pattern might be Service A, then Service B, then Service A again, and so on, with the mileage interval between each service being determined by the ASSYST system, though typically around 10,000 miles or 12 months.

What Determines Which Service Is Due?

The ASSYST system dictates whether Service A or Service B is due. It alternates between the two based on its calculations. The mileage and time intervals are dynamic and depend on your driving behavior. Some vehicles might display “Service A due in 10,000 miles or 365 days” or “Service B due in 10,000 miles or 365 days.” The system prioritizes whichever milestone is reached first.

Typical Oil Capacities for CLS Class Models

Knowing the oil capacity of your specific CLS Class model is essential for performing a correct oil change and ensuring you have enough oil on hand. The amount of oil required can vary significantly depending on the engine size and generation of the CLS.

It is critical to consult your owner’s manual for the precise oil capacity for your specific CLS model and engine. The figures below are approximate and for general guidance only. Always add the recommended amount and then verify the level using the vehicle’s dipstick or electronic oil level sensor.

Conclusion

Your Mercedes-Benz CLS Class is engineered with exceptional precision, and maintaining its performance depends heavily on timely oil changes. Understanding the correct oil change interval is not merely about following a schedule—it’s about safeguarding the engine, preserving fuel efficiency, and ensuring your CLS Class delivers the smooth, powerful performance Mercedes-Benz is known for.

By relying on the ASSYST maintenance system, selecting the proper MB-approved synthetic oil, and staying attentive to driving conditions that influence oil life, you build a maintenance routine that protects your investment mile after mile. Whether you choose professional service or prefer the hands-on approach of a DIY oil change, following the correct interval keeps your engine operating flawlessly and provides long-term peace of mind.

A well-maintained CLS Class isn’t just more reliable—it’s more enjoyable to drive. With the right oil, the right interval, and the right knowledge, your CLS Class will continue performing at its peak for years to come.

Frequently Asked Questions: CLS Class Oil Change Interval

1. What is the recommended oil change interval for the Mercedes-Benz CLS Class?

Most CLS Class models require an oil change every 10,000 miles or 12 months, whichever comes first. However, the ASSYST Plus system provides the most accurate interval by monitoring your driving conditions and engine load.

2. Should I always rely on the ASSYST system?

Yes. ASSYST calculates oil life based on real driving data—not just mileage—making it more precise than a fixed schedule. Always follow the service reminder unless you lack service history, in which case a proactive oil change is advisable.

3. What type of oil does the CLS Class use?

The CLS requires full synthetic oil that meets specific MB-Approval standards such as MB 229.5, MB 229.51, MB 229.6, or MB 229.71. Check your owner’s manual or oil filler cap for your exact specification.

4. Can I use non-approved oil in my CLS Class?

No. Using oil without the correct MB Approval can lead to accelerated engine wear, reduced performance, and potential warranty issues. Always use oils that explicitly state Mercedes-Benz approval.

CLS Class Oil Change Interval: Your Perfect Guide