Radiator Hose 2045010982 for Mercedes W204 C200 C250 C300

Coolant hose 2045010982, cross referenced to the long Mercedes-Benz form A2045010982 and to 2045017182, for the C-Class W204 range and the models that share its cooling package.

The hose runs between the coolant expansion tank and the radiator. As the engine warms, coolant expands and part of it is pushed out of the sealed circuit into the tank; as the engine cools the same hose lets it flow back, so the system stays full and free of air. It is not a straight length of rubber cut to size: the hose is formed on a mandrel to a fixed shape so it can route around the engine bay without touching the alternator or the air conditioning compressor, and the ends are moulded to the exact diameter of the tank spigot and the radiator neck. Because the shape is part of the function, a universal hose bent to fit will usually kink, and a kinked hose restricts flow exactly where the system needs it most.

Construction is EPDM rubber over an aramid fibre braid. EPDM tolerates glycol coolant and the constant heat cycling of a pressurised system, and the braid stops the hose ballooning. Even so the material has a finite life. After eight to ten years the rubber hardens, the braid starts to show through, the ends swell and begin to seep at the crimp, and eventually a pinhole opens under the clamp where nobody looks until the coolant level drops.

The warning signs are consistent: a faint sweet smell after a drive, white crusty residue around a hose end, a level that needs topping up every few weeks with no puddle under the car, and a heater that blows cold at idle. Left alone the failure is sudden: the hose splits, the coolant goes down in seconds, the gauge climbs into the red and the head gasket becomes the next job.

Fitting notes. Work on a cold engine, drain the coolant into a clean container, and release the spring clips rather than levering them off with a screwdriver. Clean both necks back to bare metal or plastic and check them for pitting, because a rough neck will cut the new hose from the inside. Do not use sealant on a moulded hose; the moulded bead is the seal. Refill with the correct Mercedes-Benz specification coolant, bleed at the highest point until the stream runs without bubbles, then run to operating temperature with the heater on full and top up once cooled.

Supplied as a single moulded hose, ready to fit. Twelve month warranty.