W212 OM651 E220 Coolant Leak – Fuel Filter Housing – Common Problem
Whilst this problem is not just limited to the E Class, it is certainly a common problem on the OM651 engine.
Many a time we come across the customer complaint of coolant light coming on, but no obvious leak. There are a few usual suspects, namely the coolant pump or thermostat housing, but one of the more common ones was to find the leak coming from the fuel filter housing.