Mercedes-Benz C200 GLC300 M274 2.0T L4 Cold Air Intake Installation Guide

Before You Begin

Tools Recommended

• Ratchet and socket set
• Appropriate screwdrivers
• Torx tools as required for your vehicle
• Pliers
• Hose clamp driver or appropriate screwdriver
• Clean shop towels
• Suitable rubber-safe lubricant
• Protective gloves

Note: Exact tool sizes may vary depending on the vehicle and intake kit configuration. Do not force fasteners or connectors.

Installation Instructions

Step 1: Identify the Factory Airbox

Before removing anything, locate the factory airbox, intake tube, air ducts and mass air flow sensor. Take a moment to familiarize yourself with the factory routing so the replacement intake can be installed correctly.

Step 2: Remove the Air Ducts

Carefully remove the factory air ducts connected to the airbox. Release any clips or retaining points without damaging the plastic components.

Step 3: Loosen the Intake Hose Clamp

Loosen the hose clamp securing the factory intake tube to the airbox. Move the clamp away from the connection point so the intake tube can be removed.

Step 4: Disconnect the Mass Air Flow Sensor

Carefully disconnect the electrical connector from the mass air flow sensor. Release the connector lock before removing it. Do not pull on the wiring.

Step 5: Remove the Factory Airbox Fastener

Locate the fastener securing the factory airbox. Remove or loosen the fastener using the appropriate tool.

Step 6: Remove the Factory Airbox Cover

Carefully separate the factory airbox cover from the lower airbox assembly. Avoid pulling on any remaining wiring or hoses.

Step 7: Remove the Factory Airbox

Remove the factory airbox assembly from the engine compartment. Check that no wiring, hoses or retaining points remain attached before lifting it out.

Step 8: Assemble the Intake Mounting Hardware

Prepare the supplied mounting hardware and bracket. Install the mounting stud or hardware into the appropriate bracket location according to the intake kit design.

Step 9: Install the Bracket on the Heat Shield

Position the supplied mounting bracket onto the heat shield. Make sure the bracket is oriented correctly before tightening the hardware.

Step 10: Secure the Mounting Hardware

Install the supplied fastener through the mounting bracket and secure it using the appropriate hardware. Tighten evenly without overtightening.

Step 11: Complete Bracket Assembly

Continue installing the supplied mounting hardware to complete the bracket assembly. Verify that the bracket is rigid and properly positioned.

Step 12: Secure the Bracket to the Heat Shield

Install and secure the completed bracket onto the heat shield. Confirm that the mounting holes are aligned before fully tightening the hardware.

Step 13: Remove the Factory Airbox Rubber Mount

Remove the factory rubber mounting isolator from the original airbox. Carefully work the rubber mount free without damaging it if it will be reused.

Step 14: Install the Rubber Mount on the Heat Shield Bracket

Transfer the rubber mounting isolator to the supplied heat shield bracket. Make sure the rubber mount is fully seated.

Step 15: Install the Heat Shield

Position the assembled heat shield into the engine compartment. Align the mounting points with the factory mounting locations and supplied brackets.

Step 16: Lubricate the Intake Connection

Apply a small amount of suitable rubber-safe lubricant to the rubber sealing strip or intake connection. This helps the intake tube slide into position without damaging the rubber seal.

Step 17: Install the Intake Tube

Insert the intake tube into the heat shield and rubber coupler. Make sure the tube is fully seated and properly aligned before tightening the clamps.

Step 18: Transfer the Mass Air Flow Sensor

Carefully remove the mass air flow sensor from the factory airbox. Handle the sensor carefully and avoid touching or damaging the sensing element.

Step 19: Install the Mass Air Flow Sensor

Install the mass air flow sensor into the replacement intake assembly using the supplied adapter or mounting location. Make sure the sensor seal is properly seated and the sensor is installed in the correct orientation.

Step 20: Install the Air Filter

Install the supplied high-flow air filter onto the intake tube. Slide the filter fully onto the intake connection and position the clamp over the filter neck.

Step 21: Reconnect the Mass Air Flow Sensor

Reconnect the mass air flow sensor electrical connector. Make sure the connector clicks or locks securely into place.

Step 22: Check Sensor Wiring

Inspect the mass air flow sensor wiring and make sure it has a smooth routing with no sharp bends, tension or twisting. Keep the wiring away from hot or moving components.

Step 23: Reinstall the Air Ducts and Intake Connections

Install the remaining air ducts and connect the intake components. Check every coupler and hose clamp to make sure each connection is fully seated and securely tightened.

Step 24: Install the Heat Shield Cover

Install the heat shield cover and secure it using the supplied or factory-compatible hardware. Confirm that the cover is properly positioned and does not contact the intake filter, wiring or other engine components.

Final Installation Inspection

Before starting the engine, perform the following inspection:

• Verify that the air filter is fully seated and the clamp is tight.
• Check every intake tube and coupler for a secure connection.
• Verify that all hose clamps are properly tightened.
• Confirm that the mass air flow sensor is installed in the correct orientation.
• Make sure the mass air flow sensor electrical connector is fully locked.
• Check that the sensor wiring is not twisted, stretched or contacting hot components.
• Verify that the heat shield and mounting brackets are secure.
• Make sure the intake system does not contact belts, pulleys, fans or other moving components.
• Confirm that no tools, fasteners or loose materials remain inside the engine compartment.

After Installation

Start the engine and allow it to idle. Listen for abnormal air leaks, rattling or contact between the intake system and surrounding components.

Inspect the intake system while the engine is running and verify that all connections remain secure. If the vehicle displays a warning light, runs poorly, develops an unstable idle or exhibits an intake-related fault, shut the engine off and recheck the installation, particularly the mass air flow sensor connection and all intake couplers.

Common Installation Mistakes to Avoid

• Installing the mass air flow sensor backwards or in the wrong orientation.
• Leaving the mass air flow sensor electrical connector partially connected.
• Failing to fully seat the intake tube or filter.
• Overtightening clamps and damaging rubber couplers.
• Allowing sensor wiring to become twisted or stretched.
• Leaving a gap between the heat shield and intake components.
• Allowing the intake tube to contact moving or excessively hot components.
• Starting the vehicle before checking all connections.

Frequently Asked Questions

What Mercedes-Benz vehicles does this cold air intake fit?

This installation guide is intended for 2015-2018 Mercedes-Benz C200, C300 and GLC300 models equipped with the M274 2.0L turbocharged 4-cylinder engine. Always verify the exact vehicle fitment and intake kit application before installation.

Does the M274 engine use a mass air flow sensor?

The intake system shown in this guide uses a mass air flow sensor that must be transferred from the factory airbox to the replacement intake system. Handle the sensor carefully and install it in the correct orientation.

How long does installation take?

Installation time can vary depending on the vehicle, intake kit and installer experience. A typical installation can generally be completed in approximately 1 to 2 hours when the proper tools are available.

Do I need to tune the vehicle after installing the intake?

Tuning requirements depend on the specific intake design and vehicle configuration. Follow the manufacturer's recommendations for the exact intake kit being installed.

What should I do if the check engine light comes on after installation?

Turn the vehicle off and recheck the installation. Pay particular attention to the mass air flow sensor, electrical connector, intake tube connections and hose clamps. If the warning remains, have the vehicle scanned for diagnostic trouble codes by a qualified technician.

Professional Installation Recommendation

This installation can be performed by an experienced DIY enthusiast with the appropriate tools. If you are unfamiliar with automotive intake systems, electrical connectors or mass air flow sensors, professional installation is recommended.

Always verify the manufacturer's installation instructions and vehicle-specific fitment information before beginning installation.