Mercedes-Benz GLA: M270 Water Pump Cover Cracking and Coolant Leak

The M270 1.6T uses an internal belt-driven water pump housed inside a plastic cover on the front of the engine block. This plastic cover is known to develop cracks at stress points, leading to coolant weeping or sudden coolant loss. Because the leak originates internally behind the front cover, it is often mistaken for a head gasket issue. Left unaddressed it causes overheating and potential head damage. Mercedes extended warranty coverage was offered in some regions.

• Coolant loss without visible external puddle under the car
• Sweet smell from the engine bay after driving
• Coolant warning light or temperature gauge climbing above normal
• White residue or staining around the front lower engine block
• Overheating episodes with no obvious external leak source

1. 1

   Inspect the front lower engine area for coolant residue or staining.

2. 2

   Check coolant reservoir level and look for discolouration.

3. 3

   Ask about coolant top-up history.

4. 4

   Have a pressurised coolant system test performed if any history of coolant loss is present.

Parts involved: Water pump.

$900 to $2,200 at New Zealand independent workshop rates. That is for this job on its own, not for the car.

An estimate, in NZD, for the repair as normally carried out. What a specific car costs depends on which part has failed and what it damaged on the way — treat this as the floor for a negotiation, not a quote.

• “Has the coolant level ever needed topping up between scheduled services?”
• “Has the water pump or its cover been replaced, and is there a receipt?”
• “Has the car ever overheated or had the temperature gauge move above the normal midpoint?”

The failure described above is documented in published sources — owner forums, technical service bulletins, recall notices and workshop write-ups — held in our fault database. The inspection instructions and the cost estimate are KickTyres’ own interpretation of them, and it is a starting point for an inspection rather than a manufacturer statement.