oad conditions, with running the cabin heat making
the overheating significantly worse. That'scounterintuitive, rules out radiator blockage as thecause. Also thermostat failure wouldn't explain whyturning off the cabin heat would cure the overheatingcondition. It turns out that Mercedes uses some kindof adjustable flow water pump to let the engine heatup quicker when cold by reducing coolant flow untilthings warm up. Great idea for raising efficiency, butwhen the flow adjustment piston gets stuck, you endaup with this issue. Here's a quick video going overwhat I wish I knew before attempting this job, like thatI should have bought the turbo cooler line O-rings a 2015 C300 Sport 4Matic with the 2.0 literM274 engine. The car was overheating under highl inadvance, or that the turbo doesn't need to be moved.oad conditions, with running the cabin heat making
