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Mercedes-Benz · Cooling

Radiator cap and expansion tank

The plastic header tank that holds the coolant reserve, with the pressure cap that sets the system's operating pressure.

Also called header tank, coolant reservoir.

How you know it is this

  • Coolant loss with nothing on the ground — it is being pushed out of the overflow
  • A hairline crack in the tank, often only visible when hot and under pressure
  • The tank bulging or the seam splitting
  • Boiling or gurgling after switch-off

Worth knowing before you buy

  • Pressure raises the boiling point. A cap that no longer holds pressure lets the coolant boil at a temperature the gauge still calls normal.
  • The tank goes brittle with heat and UV and splits at the seam. In the Gulf they are effectively a wear item.
  • A cap is a few dirhams and is the first thing to change when coolant disappears with no visible leak.

What we need to quote it. The engine code. The chassis number settles the generation, the body and usually the engine in seventeen characters — it is on your mulkiya. A photograph of the old part helps where there is more than one version.

RadiatorExpansion tank and capUpper and lower hosesThermostat and housingWater pumpAuxiliary pumpFan and clutchShroud and mountsHeater matrix and valveHeater hosesPipes and flangesTemperature sensorAuxiliary coolers
Cooling circuit — schematic, to show where the part sits. Arrangement is right; it is a diagram and not a fitment reference.

Rest of the radiator and circuit

All cooling parts
Get in touch

Radiator cap and expansion tank for your Mercedes-Benz?

Send the chassis number and a photograph of the old part. We come back with genuine, OEM and aftermarket options priced side by side, with lead times.

Mon–Sat, 8:00 AM – 6:00 PM · +971 54 303 3119 (Operations Director) · +971 54 241 0599 (Managing Director)