Ive recently discovered i redish -black color in the rad ive flushed the rad and the overflow box but seems to come back after a few weeks is there something breaking down ?

 

Your tranny fluid cools by going into the black park of your Rad on the passenger side. There could be a possible leak there. Im not to sure. I would suggest to unfortunaley taking your radiator out and filling the black part, with tranny fluid, plugging the holes. With the rad being completly empty, turn it on its side and let gravity tell you or not if the tranny fluid is leakijg into your rad. I only suggest this cause you mentioned the fluid you are discovering is red in tint.

 

Flush the entire engine coolant sytem (maybe twice) and refill with 50/50 coolant mix replacing the radiator cap with a new one from Stant. See if the problem goes away.

BTW, has there been a drop in the ATF level?

 

thanks for the advice it was the tranny cooler thats built inside the rad thats all good and done now that i did that the heater core blew so wondering if its a job i can do on my own or better to send it out i married the hoses together for now .....cheers