The cast iron in the block is starting to rust. Drain the radiator, put in a good radiator flush solution and follow the directions, then fill the radiator with the right coolant. Since you're already having rust problems, put in some rust inhibitor. You may need to clean it again and put in more rust inhibitor after things settle down.
The radiator fluid goes through your heater core (usually behind your dash) and supplies the vehicle with heat. If your radiator fluid isn't rusty in your container under the hood then your lines might be clogged up and now they are breaking and letting the old rusty fluid come through.
The transmission fluid cooled by routing it through the radiator. The fluid probably is a milky color because the radiator had failed internally allowing the coolant and transmission fluid to mix. Check the coolant and if looks milky change the radiator, coolant, and transmission fluid.
It is probably Radiator fluid that's leaking. if you have red radiator fluid. it looks purple when it heats up. I had this from my Toyota Sequoia when the leak went over the hot engine.
looks like a sensor or thermostat going into engine block
Unless your radiator has a leak, the radiator fluid stays in the radiator.
radiator fluid
it means your low on radiator fluid
looks like cilinder head gasket is defect, engine pressure is coming in radiator, and cooling fluid goes into motor
low radiator fluid
Where is the radiator to put fluid for 2001 jetta?
you have to put the radiator fluid in the overflow. This is the only way.
A bad internal transmission cooler located inside the radiator. Fluid is pumped into it and you could have an exchange of fluids. If the transmission fluid looks like "pepto" (pink) you will being going for a rebuilt transmission. Antifreeze reacts with the clutch plates inside the transmission.