Engine Performance problem
1993 Acura Legend 6 cyl Front Wheel Drive Automatic 224000 miles
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when driving the gage goes from normal to high (red zone). I did have a mechanic look into this...he told me that I need a rebuilt engine because the coolant is mixing w/ the oil. A good friend of mine did check the oil..but the color of the oil look fine. What should I do?

I doubt the coolant would mix with the oil. The oil has a higher pressure system than the coolant. What does the coolant look like? Why not have a leak down test done that is not that expensive to do and it will tell you what is wrong.