too much heat

I've got an 88 Sprint (almost a Metro...) that's been having some random cooling problems lately. I thought that I had found and fixed a coolant leak, and drove the car on a 100+ mile round trip with no problems.
Had an appointment in a town 20mi away yesterday, and had no problem getting there. After stopping for about 15mins and then driving to another part of town, however, the temp gauge nearly redlined. Radiator was low, added about 1/2gal of water after it cooled off.
It was okay for a few more miles until the next stop, after which the process was repeated - overheat, stop and fill radiator. Was out of water at that point, all with no visible leakage or "milk" in the oil.
Driving the 20mi back, the car heated to just below redline and hovered there. Stopped at the first grocery store in town to get more water, and after doin the refill again, the car was fine the rest of the way home. Frustrating as all getout.
:banghead:

Anyway, any thoughts would be greatly appreciated.
Thanks in advance,

ChromeTwinkie

Could be one of a few problems. What it really sounds like is your radiator is clogged. While you're doing the radiator, i'd put a new thermostat in also. Might as well since you'll have more room, and the thermostat is likely almost 20 years old. Check out www.car-part.com for some used radiators, or check on ebay or google for some new ones. The local parts shops will give it to ya dry with their prices on radiators.

Before I spent the money on a new or reconditioned radiator I'd do a compression check and a pressure test.

Water doesn't just disappear and a milky looking oil is only ONE symtom of a blown headgasket. It MAY be blown and NOT have one of many symptoms.

That's very true Tom. Perhaps start the car with the radiator cap off and let it warm up. See if the coolant bubbles a lot, or starts to pour out of the top of the radiator. Don't put your face over the top of the radiator though. It could spit extremely hot coolant all over your face.