1995 Dodge Dakota 5.2L V8/manual 5 speed, Radiator is full. Heater in cab works great, temperature stays normal, does not overheat. At times can smell the smokey antifreeze in cab. There is no antifreeze spray on inside floor by heat vents or on windshield inside (I was thinking heater core, but not now) Overflow is low, and I just had it filled when I had an oil change about 3 weeks ago. And steam comes from front of radiator. And hoses look fine. I did notice antifreeze had leaked out onto tray underneath radiator bottom but the radiator is full, just the overflow had a lot leaked out AND now I looked inside it and it looks like thick brown. What the heck could be the problem?

The overflow shouldn't be full anyway. I'd just keep an eye on it, if the rad. stays full and temp doesn,t show overheating it should be fine.

Your cap may be bad.

Mine failed at the seam at the top where it's crimped together. Wouldn't leak when it wasn't under pressure and only leaked until it got lower than the crimp. Took me a good 2 months to finally find it, because you couldn't see the stream when the truck was running because the fan was spraying it everywhere and it would only leak until the system lost pressure. Pressure test would be a good place to start.

It starts fine, let i warm up today, heat works fine, doesn't overheat. The fluid in the overflow tank looks like a brown sludge, what is this. Racking my brain.

And I checked the cap, nothing leaking from it.

If you don't know the history of the truck, I would drain and flush the cooling system...backflush the system with a garden hose...sounds like someone poured stops-leak in the radiator due to the goop. After you flush it, pressure test the rad and have it dipped and cored, then reinstall and refill the cooling system. Sounds like you have a hairline leak somewhere in the radiator. Sounds like you are getting coolant vapors/smell from the engine compartment through the fresh air circulation.

It was the radiator, now she has a new one.