Transmission fluid in radiator. milky and oily looking antifreeze overflowing from cooliant recovery tank

The transmission cooler is usually located inside of the radiator. I would take it to a radiator shop to have it tested as loosing trans fluid and mixing antifreeze into the trans fluid will ruin that expensive transmission very quickly.

First thing to do is check the transmission fluid level and check for leaks. If the transmission is very low on fluid, for example a cooler line broke, it would cause this situation due to no pressure. If you do not see any outside leaks, but transmission fluid is very low, check your radiator overflow tank, if it is overfull and milky, this would mean the Trans cooler that goes through the radiator is leaking fluid into the coolant system.

Sounds like either a bad head gasket, cracked head, or block. Also you may want to go to a shop and have them check the transmission and radiator coolant lines. You could have trans fluid getting into your coolant.

You are correct to be concerned. Look and see if the transmission has any vacuum lines. If it does, check the lines by disconnecting them and see if transmission fluid is inside the lines. If there is transmission fluid present, the engine is drawing the fluid out of the transmission and burning it in the combustion chambers.

Radiator overflow- Check color of antifreeze in overflow tank. The radiator can have 2 chambers. If the chambers breach, the fluids can mix. Since the overflow can vent the excess fluids, it can provide an outlet for the trans fluid.
Leaks, most common. There should be staining and presence of oily residue. Check for lower cooling coil assembly. Some Makers use a separate cooling unit similar to a steering cooler if a 2 chamber radiator is not equipped.
You may be able to simply go to a quick change oil shop and drive over their service bay. They could check for leaks.

Check the oil and also transmission fluid, one of them should also be milky. If it's the oil that is also milky then most likely cause is blown headgasket. If it's transmission fluid, then the radiator probably has failed in the transmission cooler section. If the transmission fluid is milky, then you also need to have the fluid flushed and the trans. filter changed after fixing the radiator.

Your transmission cooler in the radiator tank is probably leaking, A radiator shop could probably replace the cooler but if the radiator is old you should replace the whole thing.

what kind of antifreeze?...radiator fluid?...if Rad fluid..look for your overflow tank, and add it there. The cap may be yellow, and may have "rad fluid only" printed on it.


gas line antifreeze goes directly into the fuel filler
windshield washer winter(antifreeze) goes into the wishy washy reservoir

The best method is to fill the radiator up with a mixture of antifreeze and water. The mixture details should be on the antifreeze container. Once the radiator is full let the car run until the thermostat opens up and you should see the level of fluid go down in the radiator. Fill the radiator again while the thermostat is opened. Then add fluid to the overflow tank to the fill line. That should do it. If you have put in too much it will run into the overflow container when it is not needed in the car.

It sounds like the headgasket needs to be replaced. Please be sure to have the mechanic who replaces the head gasket also change the oil immediately before starting the car. If you have anti-freeze in the oil, it could blow the engine later on down the road!

the transmission oil cooler is on the lower part of the radiator. it might have a hole inside. you need to replace the radiator and flush the transmission fluid several times