Mercedes-Benz CLK320 coolant contamination in oil pan with potential engine issues on Mercedes-Benz CLK320

Some Mercedes-Benz CLK320 owners report experiencing coolant contamination in the oil pan, which can occur due to a failed O-ring between the timing chain rear cover and the engine block. This issue may lead to coolant mixing with the oil, potentially resulting in engine damage if not addressed promptly. Additionally, some owners of the Mercedes-Benz E Class W212 with the M274 engine have identified the engine oil cooler as a source of contamination, resolving the issue by replacing faulty components and flushing the system. Symptoms of coolant contamination often include a low-coolant warning appearing regularly, indicating a cooling system problem. Common causes of this contamination include rust from corroded parts, oil leaking into the coolant due to a faulty head gasket, or the breakdown of old coolant. Regularly checking the engine oil level and ensuring it remains clean, along with flushing the radiator and monitoring coolant for oil contamination, are essential steps for owners. In some models, such as the M113 V8, hardened O-rings between the engine oil cooler and the filter housing may also contribute to oil/coolant contamination, and addressing this can be a cost-effective solution compared to radiator replacement.