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Lion Yard Trading
Mercedes-Benz · Cooling

Heater control valve

The valve that meters hot coolant into the heater matrix, deciding how warm the cabin gets.

Also called heater valve, duo valve.

How you know it is this

  • Heat on one side of the car and cold on the other
  • Heat that cannot be turned off, whatever the climate control is set to
  • No heat at all with a hot engine and a clear matrix
  • Coolant leaking under the bonnet near the bulkhead

Worth knowing before you buy

  • Different temperatures left and right is the signature, because many of these valves are twin units with one side per zone.
  • Far cheaper and far more accessible than the matrix behind it. Always ruled out first.
  • They leak as well as stick, and a leak here drips onto the bulkhead rather than into the cabin.

What we need to quote it. The chassis number. 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 heating and auxiliary coolers

All cooling parts
Get in touch

Heater control valve 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)