Thermostat M276 for Mercedes-Benz

OE spec engine thermostat assembly, engineered for Mercedes Benz vehicles with the M276 V6 petrol engine, 3.5 NA and 3.0 biturbo. Restores correct warm up time and stable operating temperature, protects against overheating and weak heater performance. Sold per unit, variant specific as supplied with housing and sensor where applicable.

What this is / isn’t:
Included: 1× thermostat assembly

Important: Match by VIN and engine code M276. There are multiple sub variants, M276.9xx 3.5 NA and M276 DELA30 3.0 biturbo, including AMG 43. Housings, outlet angles and connectors can differ by year and model. Always confirm by OE part number.

Key Features:

• Precise temperature control: OE matched opening temp and flow for stable engine and cabin heat.

• Integrated housing and seal: Direct bolt on replacement to minimise leaks and comebacks.

• Correct sensor or actuator logic: Communicates with the ECU for accurate warm up and efficiency.

• Durable materials: High temp plastics and elastomers resist glycol and thermal cycling.

• Exact fitment: Factory mounting points for a no mod install.

Compatibility:
Common Mercedes models using M276 V6, confirm by VIN or OE:

• C Class W204, W205 C350, C400, C450, AMG C43 where fitted

• E Class W212, W213 E300, E350, E400, E450

• CLS C218, C257 early CLS350, CLS400, CLS450

• S Class W222 early, W221 late select markets S300, S400, S450 where M276 fitted

• GLK X204 late, GLC X253, GLE W166, W167, ML W166, GL X166, GLS X166, SLK R172, SLC R172, G W463 select trims
  Drivetrain: 2WD and 4MATIC where applicable. Markets vary, always match by VIN.

Options, engine or sensor variations:

• M276 3.5 NA → specific housing orientation and sensor connector.

• M276 3.0 biturbo and AMG 43 → revised housing and actuator spec, check supersessions.

• Model year revisions → outlet angle, hose size or plug style may change.

Typical OE reference families, guide only:
A276-200-… , A276-203-… with supersessions by model year and market.
Always order by the exact OE part number on your vehicle or confirm via VIN.

Symptoms of a faulty thermostat:

• Slow warm up, temperature gauge low or fluctuating.

• Overheating in traffic or under load.

• Weak cabin heat, fault code P0128 or related temperature errors.

• Coolant seepage around the housing, dried crust at joints.

Installation notes, pro tips:

• Work on a cold engine. Drain coolant below housing level.

• Replace the seal or O ring, clean mating faces, torque bolts evenly to spec.

• Refill with Mercedes approved coolant, MB 325.x spec, bleed the system thoroughly.

• Verify fan operation and hose temperatures on first heat cycle, clear stored codes after a road test.

• Inspect adjacent hoses, clamps and plastic tees for age related brittleness.

What’s included / not included:
✅ 1× Thermostat assembly with housing and seal, sensor or actuator if supplied
❌ Coolant, hoses, clamps, water pump, radiator, extra sensors, hardware

Q&A
Q1: How do I confirm I have the M276 engine and the correct sub variant?
Check your VIN data card for the engine code. Your VIN will map to the exact thermostat part number.
Q2: Do I need coding after replacement?
Coding is usually not required. Clear any fault codes and verify operating temperature with a scan tool.
Q3: Which coolant should I use?
Use Mercedes coolant meeting MB 325.x specification, mixed to the correct ratio.
Q4: What else should I replace?
Consider a coolant service, inspect hoses and clamps, replace brittle plastic fittings.

Why choose TOParts:
OE grade engine components for Mercedes Benz with precise fitment, correct specs and long term reliability, trusted by panel shops and independent Mercedes specialists across South Africa.