Mercedes-Benz C-Class: How to Replace Serpentine Belt
The serpentine belt powers every accessory on the engine. When it wears, belt slip occurs and it will decreases the A/C, power steering, and charging system performance. Continue reading to find out how to replace the serpentine belt on your Mercedes-Benz C-Class.
This article applies to the Mercedes-Benz C-Class w204 (2007-2014).
The alternator, A/C compressor, and power steering pump are solely powered by the rotating motion of the serpentine belt. It rides along the pulleys that are bolted or pressed onto these components. Over time, wear occurs from temperature changes and dirt entering into the engine bay. This causes the belt to stretch, crack, and eventually break. When this happens, you lose power assisted steering, air conditioning, and your charging system will no longer be operational.
Materials Needed
- 3/8" or 1/2' ratchet (preferably with a long handle)
- T55 Torx socket
- 17mm socket or wrench
- Small punch, cotter pin, carpenters nail etc.
- Flat head screwdriver
- Plastic door panel tool (optional)
- Small extension (optional)
The M271 (4-cylinder) is found in the C180, C200, and C250. The C230, C300, and C350 is found with the M272 (6-cylinder) engine. Both engines will be covered, and the steps will be designated as V6 Engine (272) and I-4 Engine (271) for easy identification.
Step 1 – Remove engine cover and intake hoses
V6 Engine
The 272 will require you to remove the front engine cover. Simply pull forward and up to detach it. You will hear the four plastic clips on the bottom side of the cover pop free.
- Remove the dipstick. The red handle can be seen at the top of the engine.
- Remove both the left and right intake hoses. They pop out of place with an upward pull.
I-4 Engine
- Before removing the serpentine belt, first remove the intake hose. There is one clip holding the hose to the radiator support. It must be turned 90 degrees.
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There are also two clips holding the hose to the elbow. Pry these clips up to unlock them, and then pull the hose towards the front of the engine.
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You will now need to loosen two hose clamps. These hold the hose running across the engine in front of the cooling fan.
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Also remove the smaller hose above the power steering pump.
Step 2 – Remove the serpentine belt
V6 Engine
- Using your 17mm socket, turn the tensioner counterclockwise to remove tension from the belt.
- Insert your punch or rivet into the tensioner. This will lock the tensioner in place, and keep tension off of the belt.
- Un-route the belt from the engine pulleys, and out of the engine.
I-4 Engine
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Once you have removed the hose, use your ratchet and your T55 Torx socket to remove the tension from the belt, and slide it off the pulleys.
Step 3 – Install the new serpentine belt
Begin by routing the serpentine belt in the correct path around the pulleys. Make sure the last pulley you will be sliding the belt onto does not have raised edges; otherwise, it will be difficult to slide on.
The belt may need to be pulled with some force to make it slide onto the tensioner pulley. Install any hoses/covers you removed, and you have finished installing you new serpentine belt!
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