I have a 96 cavalier that started over heating last week. Me knowing nothing about cars gets a kid to help me at the grocery store he says my coolant was empty so I put water in it. I have to put water in it everytime I drive over 30 miles. It seemed like as long as I kept water in it it wouldnt over heat. Until now no matter if I have water in or not it still overheats. Sometimes and I know this is weird but it will get almost to the hot point on the gauge then all of the sudden start to cool down. I‘ve noticed if I run my heat it causes it to overheat too. Plus sometimes my check gauges light will come on. I just bought this car like a little over a month ago. I don‘t have the money to fix it please tell me how I can fix this. My church gave me money for this car it‘s my only transportation at the moment. Please help me !
Okay well all the other answers are good, but they neglect the weeper hole on the water pump. To check whether it is leaking from there or not simply fill the car with coolant or water (yes water will work for this test) and start it. After you start it open the hood and prop it open then hold your hand close to the serpentine belt (be careful though, get it caught in there and it's god aweful pain and possibly a hospital visit). If it gets wet aka water being slung about by the belt, the water pump is leakin from the weeper hole and needs to be changed. If not, change that thermostat and check your oil. If it's milky and grey-ish in color you've blown the head gasket from overheating or cracked the head. Neither one of which is very good but some good block seal (i recommend bars leaks copper block seal) will get you some extra mileage out of it until you can afford another car. If the head or gasket is cracked anyway. Either way I hope it's that thermostat, good luck.
The fact that you are losing coolant means there's a leak somewhere. If you cannot see any coolant leaking down to the bottom of the car in puddles of green liquid, then you might have an internal leak normally caused by a blown head gasket. If that's the case, I'm sorry to say it, but for someone in your position, you would have to get rid of the car, because to fix it would cost you more than the car is worth. If you're running the 2.2L 4 cylinder engine, then a blown head gasket is a safe bet because I know this engine to be notorious for that. Do what you can for now, but unfortunately, it doesn't sound good at this point.
