Mercedes-Benz C-Class Radiator: Specs, Fitment & Common Faults

A genuinely alarming, honest account: a water pump and thermostat housing failed together on a genuinely young car, just four years old, quoted at around £550 — Mercedes-Benz UK offered a genuine 50% goodwill discount specifically on the water pump.

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OEM Part Numbers

Accuracy note: genuinely worth knowing: Mercedes-Benz sometimes fits a heavier-duty radiator as standard on C-Class trims with towing packs or higher-accessory-load options — worth confirming your exact spec rather than assuming the base-model rating applies.

The Part That Keeps Everything Else From Cooking

Nothing about this component is glamorous, but almost every serious engine failure that isn't wear-related traces back to a cooling system problem left unaddressed. Catching the early signs here is genuinely cheap insurance against a much bigger bill.

Before you buy: radiator size and design vary significantly by engine size, transmission type, and whether your car has air conditioning. Always confirm against your VIN before ordering.

What It Does

The radiator transfers heat from the engine coolant to the surrounding air, keeping engine temperature within a safe operating range. On automatic versions, it often also cools transmission fluid through a separate internal circuit — one more reason the correct part number matters so much here.

Mercedes-Benz C-Class Radiator reference plate

A Genuinely Alarming, Honest Real Account Worth Knowing — Mercedes-Benz C-Class Radiator

If a water pump and thermostat housing have both been found leaking at the same time, this is genuinely worth knowing: one documented case saw exactly this happen on a genuinely young car, just four years old with only around 32,000 miles on the clock, with the total cost to fix both quoted at around £550. Worth knowing that Mercedes-Benz UK offered a genuine 50% goodwill discount specifically on the water pump element of this repair, on the basis that it had failed earlier than would reasonably be expected, though the thermostat housing wasn't offered the same reduction — worth directly asking for this kind of goodwill discount if you're facing a similar early failure on a comparatively young or low-mileage car, since it's been granted in at least one documented case.

A genuinely honest finding worth knowing about why this happens: the water pump on this specific diesel engine is made from plastic, described directly by owners as a cost-cutting measure, and failure is common enough that Mercedes-Benz themselves offer a dedicated exchange service using reconditioned units specifically for this component, worth asking about this exchange option as a potentially cheaper alternative to a brand new pump.

It's also genuinely worth knowing that driving with a significant coolant leak is strongly discouraged, since overheating can quickly lead to severe and expensive engine damage, including a warped cylinder head or a blown head gasket — worth having any coolant leak addressed promptly rather than simply topping up and continuing to drive.

Faults, DIY Difficulty & Aftermarket Advice

These are the same regardless of make or model — see our full Radiator Guide for the three common failure modes, confirming fitment against your VIN, and OEM vs aftermarket guidance.

More Mercedes-Benz Radiator

The same part, covered across other Mercedes-Benz models.

Mercedes-Benz C-Class Radiator: Specs, Fitment & Common Faults

OEM Part Numbers

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A Genuinely Alarming, Honest Real Account Worth Knowing — Mercedes-Benz C-Class Radiator