Mercedes-Benz CLS C257
Weaknesses, engine ratings and buying advice
367–435 PS
3.0L I6 Turbo Benzin
The Finest Inline-Six Setting — M256 in the CLS
Fun to Drive!Generations
Engine Overview
The Mercedes-Benz CLS C257 is available with 9 engine variants — from 116 to 435 hp.
The Mercedes-Benz CLS 220d (Diesel, 194 PS) has the OM654 (2.0L Diesel) — rated: "Be Careful", 11 known weaknesses.
The Mercedes-Benz CLS 300d (Diesel, 245 PS) has the OM654 (2.0L Diesel) — rated: "Be Careful", 11 known weaknesses.
The Mercedes-Benz CLS 350 d (Diesel, 286 PS) has the OM656 (2.9L R6 Diesel) — rated: "Be Careful", 6 known weaknesses.
The Mercedes-Benz CLS 350d (Diesel, 286 PS) has the OM656 (2.9L R6 Diesel) — rated: "Be Careful", 6 known weaknesses.
The Mercedes-Benz CLS 400 d (Diesel, 340 PS) has the OM656 (2.9L R6 Diesel) — rated: "Be Careful", 6 known weaknesses.
The Mercedes-Benz CLS 400d (Diesel, 330 PS) has the OM656 (2.9L R6 Diesel) — rated: "Be Careful", 6 known weaknesses.
The Mercedes-Benz AMG CLS 53 (Benziner Mild-Hybrid, 435 PS) has the M256 (3.0L I6 Turbo) — rated: "Be Careful", 9 known weaknesses.
The Mercedes-Benz CLS 350 (Benziner Mild-Hybrid, 299 PS) has the M264 (2.0L Turbo EQ Boost) — rated: "Be Careful", 12 known weaknesses.
The Mercedes-Benz CLS 450 (Benziner Mild-Hybrid, 367 PS) has the M256 (3.0L I6 Turbo) — rated: "Be Careful", 9 known weaknesses.
Vehicle Weaknesses
| Weakness | Cost | |
|---|---|---|
| Recall: turbocharger oil return line — fire risk Retaining screws for the turbocharger oil return line may be mixed up. Incorrect screws reduce clamping force, oil can escape and ignite. Symptoms: Oil smell in engine bay, smoke, in the worst case engine bay fire | Low |
Top Reported Issues
Alternatives
Known Problems and Issues
A total of 45 weaknesses have been documented for the Mercedes-Benz CLS C257 (2018–2024) — 38 engine-related and 7 vehicle-related. Typical issues affect Other, Suspension, Electronics, Gearbox.
CLS (OM654, 2018–2024) — Be Careful: Rocker Arm and Camshaft Wear, Electric Coolant Pump Leaking — Recall, NOx Sensor Defective — AdBlue Fault and Start Inhibit. Power: 245 PS.
CLS (OM656, 2018–2024) — Be Careful: Recall Coolant Pump — Fire Hazard (Action Code 2090008), Bosch CP4 Pump Sensitive to Fuel Quality, Coolant Pump Leaking — Fire Risk (Recall). Power: 286 PS.
CLS (OM656, 2018–2024) — Be Careful: Recall Coolant Pump — Fire Hazard (Action Code 2090008), Bosch CP4 Pump Sensitive to Fuel Quality, Coolant Pump Leaking — Fire Risk (Recall). Power: 330 PS.
CLS (OM656, 2018–2023) — Be Careful: Recall Coolant Pump — Fire Hazard (Action Code 2090008), Bosch CP4 Pump Sensitive to Fuel Quality, Coolant Pump Leaking — Fire Risk (Recall). Power: 340 PS.
CLS (OM654, 2019–2024) — Be Careful: Rocker Arm and Camshaft Wear, Electric Coolant Pump Leaking — Recall, NOx Sensor Defective — AdBlue Fault and Start Inhibit. Power: 194 PS.
CLS (M256, 2018–2024) — Be Careful: 48V ISG Battery Failure, Camshaft Adjuster Solenoid Leaking — Oil in Wiring Harness, Elevated Oil Consumption at Higher Mileage. Power: 367 PS.
CLS (M256, 2018–2024) — Be Careful: 48V ISG Battery Failure, Camshaft Adjuster Solenoid Leaking — Oil in Wiring Harness, Elevated Oil Consumption at Higher Mileage. Power: 435 PS.
CLS (M264, 2018–2024) — Be Careful: Exhaust Valves Defective — Cylinder Head Damage (Serial Defect), HV Cables and E-Motor Integration Defective (PHEV), Chain Tensioner Loses Tension — Chain Rattling. Power: 299 PS.
What to watch out for with the Mercedes-Benz CLS? See the detailed listing of all engine and vehicle weaknesses in the sections above.
Frequently Asked Questions
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Last updated: February 2026 · All information without guarantee