I have had to add at least a gallon of antifreeze/water to my radiator in the last couple of thousand miles. I don't know where the fluid's been going?

I can't see any holes in any of the hoses, the water pump's not leaking and I have never noticed or smelled steam either. There's no puddles of fluid or even drips on the ground in the morning as well.

There's no water in the oil or vice versa. It's not overheating but it does take a while to warm up. In fact, it takes so long to reach normal temperatures I was thinking I had a bad thermostat that was stuck open.

Any ideas of where to start looking would be greatly appreciated

 

I would tighten the hose connections. You could be losing just a little at a time, and have it evaporate before it ever hits the ground.

 

Take a look at your radiator cap! Loose or worn out caps can sometimes be the cause of this. Good luck

 

I'm having the same problem with my '84 Bronco. Once per month, I start overheating, then I check the fluid to find that it is low. I'm just sitting here thinking that it might possibly be my heater core. The reason I think this is that when I run the heat, and sometimes not, I notice a drifting "smoke" from the defrost vents on the dash. There's no real odor to this smoke, like burning wire or oil or anything, so I'm thinking it might be a steam. I'll have to check it out. You might do the same. Maybe you're not getting smoke/steam, but the heater core might be leaking discretely.

Thanks for the question.

 

BTW, if you have an after market radiator, check and see if you have openings for extra hose's. I had water leaking from one of these and a bad radiator cap.

 

I had trouble with mine leaking small amounts of coolant at the radiator hose connections. First at the water neck on the upper, then at the radiator on the lower. They could not be fixed by tightening. I put new hoses and new clamps and this solved the problem. Also, Broncos almost always lose coolant at the coolant recovery tank cap. I finally fixed this on my Bronco by simply putting duct tape around the outside of the place where the cap snaps on. If you take the cap off and look at the tank, it has four grooves in it for some stupid reason and coolant comes out of them. Also the cap does not fit on tight. By putting a strip of duct tape around there, it covers the grooves and makes the cap fit tight. Finally, when you are filling the radiator back up after fixing your leaks, put in some Bars-Leaks sealer to seal any tiny leaks. Even new cars coming out of the factory have this in them.