So on my 2008 ranger 2.3 I have a coolant leak where the upper transmission line goes into the radiator. The actual line screws into a metal fitting that is screwed into the plastic tank. It is leaking coolant where the metal fitting goes into the plastic tank. No leaking of tranny fluid, just a small leak of coolant. Is this something that can be fixed or resealed or does it mean that the plastic is cracked and the radiator is toast? All the posts I have seen about this have been leaking tranny fluid from an o-ring on the fitting but nothing about a coolant leak. Anyone have an idea?

 

Sound like a cracked tank. Replace the radiator.

 

That was my first thought too. I have since removed the line and the metal fitting from the tank and found no cracks. It appeared that there may have been a gasket of some sort between the metal fitting and the tank where you can see the metal "ring" of the actual cooler. So I cleaned it all up, blue siliconed at the base of the fitting where it meets the tank, tightened it up and let it dry overnight. Ive driven it around a bunch since then, getting it good and hot, and it seems to be fixed. No more leak. Hopefully it lasts.

 

The trans cooler inside of the radiator is a separate item. The metal fittings you see on the outside thread directly over the male threads of the trans cooler.

Essentially, it is a regular heat exchanger type unit, that is placed inside the end tank on the radiator. The radiator is sealed by rubber gaskets on either side of that threaded fitting. It looks similar to this, but shaped different.

I had some of them at the house when I tore my old radiators apart. If you see trans fluid leaking, there is a problem with the core. If coolant is leaking, then your issue is with the gasket used to seal the tank. If they need replaced, remove ONE AT A TIME and do not pull both fittings off the radiator at once. If you do, the heat exchanger inside will likely fall in, and you'll have a hell of a time trying to retrieve it from inside the tank.