I am having trouble keeping coolant its nice green color. Recently I have been needing to flush my coolant every time I have to make me three hour journey from school to home. After the trip I look at my coolant and it has gone from its normal green to a tea brown. It is definitely not a blown head gasket as that would be more of a milky brown. I average 85-100mph during this trip and I am curious if that is the reason for the change in color.

 

I have seen this in dsm's, now its possible you have rust in your system, which I doubt. Also in dsm's I have seen instead of blown headgaskets, the block would be cracked, leaking oil into the coolant chambers but also leaking coolant into the oil pan. You sure you oil doesnt look milky?

 

By flushing it, are you attaching a garden hose to your system while running? Or are you just draining the radiator and filling it?

 

I never flush the system since I have taken the radiator out numerous times for turbo swaps. Also the car has 29k miles on it and shouldn't need a flush. I am positive the discoloration is not due to oil.