I don't think my Dad did much tuning up, if it was the timing belt and water pump, I think they were replaced around 135K mileage. The viscosity seemed very clear, and the color is dirty water or thin brown liquid, my Dad's guess was old radiator fluid. The smell is very similar to water vapor, nothing too funky like burned oil. Also, I know that hot oil is usually thin at first, but then it leaves black or acidic spot where it dripped with thin tar-like residue, but there was no residue left on the ground later on.
Is there a diagram or schemetics to check for these kind of hoses without taking out the engine?