Any Mopar Tech's here - Grand cherokee 4.7 loosing coolant.

MileHighDart said

Well I tried a couple things you guys suggested. I took the rad cap off, clamped off the overflow tube. Started it up from cold and watched to see if it started pushing antifreeze out. Before it got 1/4 of the way warmed up it was pushing antifreeze out the top of the radiator.
So then I put the cap back on and waited for it to get up to temp, once it was warmed up, the upper radiator hose was very hard, maybe not rock hard, but much harder to squeeze that when it was cold.
So to me that's two indications that I might have a head gasket problem. Might go a step further and try the head gasket leak detection tool, or pull the plugs and look at them.

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Usually a starting head gasket leak will pressurize the cooling system before the coolant starts going back into the motor because if it, so you are probably ok as far as the rest of the motor but it sure can't hurt to check the plugs.
The hoses will only pressurize to the point the cap doesn't hold it back any longer.
That is when you start loosing coolant and overflowing the recovery system.
When it cools down it creates a vacuum and pulls back what was in the recovery tank.
The recovery tank being empty is a good sign actually, because it hints that the leak is so small so far that it can still build a vacuum and pull coolant back into the radiator.