Q: oil in coolant, coolant leaks, engine overheats

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last year all radiator hoses and water pump was replaced, last week a mechanic mentioned i had oil in my coolant and recommended I steam clean my engine, which I did. The first day after cleaning my engine ran very rough, The second day after cleaning engine still ran rough and ovrerheating problem occurred.

My car has 300000 miles.
My car has a manual transmission.

If an engine runs roughly right after steam cleaning, typically that is caused by moisture that has gotten into electrical components, wiring, or terminations. Steam cleaning can only be performed if all sensitive engine components are carefully protected. Steam cleaning can only "clean" parts and thus cannot fix problems such as engine oil leaking into the cooling system. If you do have engine oil in the coolant that means that the barriers between these two systems (cooling system versus the engine oil lubrication system) have been breached. Once frequently encountered breach is a failure of the head gasket but there are other possible breaches such as a cracked engine block. If a head gasket fails, that can be accompanied by engine overheating so the two issues that you have, the oil in the coolant and the overheating should be looked at together in one diagnostic. If you desire that this problem be diagnosed by a certified Mechanic, dispatched by YourMechanic right to your location, please request an engine overheating diagnostic and the responding certified mechanic will identify the problem and estimate a repair strategy to get your car running again. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.

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