My '97 Chevy Lumina has just gone over the hill on the mileage side to the 100K club, and I have just started having coolant issues where the engine will run warmer than its supposed to, and it has actually overheated on 2 occasions. My first repair for this issue was to replace a kinked hose that ran from the antifreeze reservoir to the radiator. After I did that, it ran great for 2 days. I have also found that i have a leak in my reservoir, so the antifreeze will slowly leak out. Today on my drive into work, i noticed the car was running warm again, so i pulled over and filled up the holding tank up to the 'hot' line with antifreeze and let it run for a bit, but it didn't seem to do me much good. What's the problem now?