03 MCS 166k . I'm in the process of removing my siezed engine and when I pulled the oil cooler lines quite a bit of rust came out as very small graines . There was alot . Is this normal or could this be why I was loosing coolant

 

No thats not normal...

 

Actually to be more accurate the rust came put of the lines when I disconnected them . It came out as alot very tiny rust flakes . I was diligent changing the coolant when i bought the car a few years ago . Perhaps the previous owner was not.
In any case the engine is toast and the used engine I purchased has an oil cooler so I'll be using that . Now that I'm thinking about it I have the heater core lines disconnected so I should probably flush the heater core
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