Cooling-system maintenance is often overlooked in favor of oil, filter and tire changes, even though coolant plays a critical role in keeping the engine within its proper operating temperature. A routine inspection can also reveal faults that have been developing unnoticed.
That is what happened to a customer of mechanic Juan José Ebenezer. The vehicle had arrived for an oil change, but the preliminary checks revealed oil mixed into the coolant. Ebenezer described the discovery as a maintenance “disaster” and examined the expansion tank before assessing the likely cause.
The coolant in the vehicle should have been yellow, but the inside of the tank was heavily contaminated. Ebenezer said the liquid was almost entirely oil and advised drivers to inspect the coolant so the problem can be detected before the entire system becomes contaminated.
The mechanic identified two possible sources: a failed head gasket or a defective heat exchanger. He could not determine the exact cause at that stage, but warned that the customer would need a much more extensive and expensive repair than the planned oil change. The inspection could require checking the cooling system, the head gasket and, in the worst case, whether the cylinder head or engine block had developed cracks.
The coolant level is among the basic checks recommended for drivers. It should remain between the minimum and maximum marks in the expansion tank, and the check should be performed with the engine switched off and cold, on level ground. The system should be filled with coolant rather than simply water.
Coolant also loses its properties over time and needs to be replaced periodically. Maintenance should cover the entire system, including the hoses, clamps, belt and radiator. Detecting oil in the coolant early can help prevent a serious engine failure or, in the most severe scenario, engine damage.
Sources: Motorpasión.