you have had the car for four months and have never looked at the coolant before? I assume you can just drain this, flush it good and refill it if it is not a oil/coolant leak and is just a dex cool mixing issue........
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Need to double check everything, check your O2 sensor, make sure those connections are good.
As for the header hitting the fan, I donno what to say about that, all I know is I have a 1-3/8" radiator and TOGS and I can put my hand between the fan and header just fine.
Post up pics of what you did....