Coolant disappearing from overflow reservoir.

[SonOfDolomite]

My 95 is using up all the coolant from the overflow reservoir, but I have no idea where it is going. I cannot find any obvious leaks, no coolant smell when using the heater and no water in the oil. After refilling the overflow I drove about 10 miles and checked the fluid level, it was bone dry. Any ideas on where this stuff is going?

**Also, I made sure the radiator was topped off before adding more fluid to the overflow.

[wiswind]

That is a LOT of fluid....if it were going into your oil....you would know it. Yes, could be a head gasket or lower intake manifold gasket (into the cylinder(s) )...which would require very prompt repair.
All that coolant into the cylinder(s) within 10 miles?....I would think that you would be putting out a white steam cloud....

....but this is what I would try....

Place a clean piece of cardboard under the car....and see if you get any drips onto it.....and look up from that point.

One well known leak is from the "timing chain cover gasket". Basically....the front cover. The front cover is what the water pump is attached to. Also includes the oil pump....and the big pulley that comes out of the front of the engine....which provides the power to the serpentine belt....

The gasket is cheap.....the labor is very expensive.....I was quoted well over $1200.
Step 1 of the official instructions.....Remove Engine from car. I have put a leak sealer into my antifreeze to keep it under control. But my leak is VERY slight.....If the leak is out from the timing cover....it will leave spots on your cardboard....passenger side.....near the oil filter....should be just behind the oil filter.

Don't forget to consider a hose, or hose clamp. Including the heater hoses. I like to check the cheap and easy things first.....and often find that these are the cause of the problem.

The other possibility for so much volume of coolant in such a short time is that you still had air trapped in the system...even after filling the radiator and overflow bottle....air will be still trapped ....and much of the volume that you went through was from the air working its' way out of the system....and being replaced by coolant from the overflow bottle.