95 Grand Am Overheating Problems - Need Veteran's Help! $$ reward.

[shadowmaker2]

I have had this car for about 4 months. It is a 3.1 V6 GA 1995. When I first bought it it started overheating before I got it home. I replaced the water pump, which looked brand new, went to change the thermostat and it didn't have one. The fan worked. I took it to my uncle's garage and let it set for a while while he worked on it. He wired the fan directly to the battery and changed out the coolant, and put a switch on it for me to turn the fan off and on. He did a pressure test to make sure my head wasn't cracked and left 100 pounds on it for an hour and a half and said that he came back and it was still at 100. From then on it seemed to run fine as long as I turned on the fan, but the service engine soon light came on after about 10 minutes no matter what. Then the fan switch melted, so I took the metal piece from the toggle switch and cut it to fit the wires together and just unplugged them when I got out of the car. A while later a fuse blew and my power locks and cigarette lighter stopped working. I kept driving it. One night me and my friends went to some waterfalls and I had a little too much to drink and my friend drove us home. He punched the gas real hard on the on ramp. The next day I had to drive about 45 miles away and it overheated so I put some water in it. On the way back I put in antifreeze and it did fine. The next day I took another trip and it overheated 3 times. I have since made 6 45 mile trips and went through 5 gallons of antifreeze and about 10 gallons of water. It eats the antifreeze like crazy. There doesn't seem to be any leaks but the fan is still working. I bought a 50 amp toggle switch I am going to put in today, and I replaced the fuse for the cigarette lighter and now it works. I used the alarm fuse, so I'm going to go and buy some more fuses and check them all. I have no idea what is wrong, but I love this car and I would hate to sell it, I worked very hard for it and paid over a thousand dollars for it. The hoses all get very hot when it overheats but the engine does not. The fan is still working. I still do not have a thermostat because as soon as I put one it it gets hot twice as fast just sitting there. Everyone has their own opinion as to what's wrong with it. One person told me it might be an O2 sensor, one said my radiator is bad, the mechanic said make sure I put antifreeze in it and it should run fine, from researching this board I found one guy saying pontiacs have a cheap plastic hose that is 12 bucks that usually needs replacing, but I am new to working on cars and I'm not sure where to find it or how to eliminate what might be wrong until I am sure what it is. Any help would be greatly appreciated. If someone tells me on here how to fix it and it turns out to be right, I would be so happy that I would paypal them some money just for being so helpful.
Another thing: the mechanic said that the air conditioner/heater thing was iced over and he just hit it with a hammer and said don't use the air conditioner. I do smell antifreeze sometimes. My muffler is a little lower than it should be because a clamp rusted off. That's all that I can think of and I'm sorry if it's a little jumbled, I just know that every detail probably counts when you can't look at the car. All the fluids are full, the brake pads and rotors need replaced, I'm doing that Wednesday. Ok, that about does it. Pontiac Excitement!

[shadowmaker2]

When its hot and I start my car after sitting all night, the spark plugs are misfiring or something because I'm not getting smooth acceleration until i get going real good. When I first bought the car it seemed to have a lot more power.

[skibum1111]

It sounds like during all this heating and cooling cycles that you have either cracked a head or blown a head gasket. Mine was doing the same thing as yours cold, and when I pulled the plugs out one smelled like antifreeze, the others were fine. Check your plugs, see if there is coolant on them. If that's the case, its either a bad head or bad gasket. The pressure test on mine came back ok as well, and when we got the head off it was cracked in 3 places and the gasket was blown.

[GTP Dad]

A cracked head is not out of the question given the fact that the car does not run well and the fact that it has overheated so many times. If you find that the plugs are OK then the problem has to be else where.

If you are going through that much coolant you should see water in the oil or all over the engine if you have a bad intake manifold gasket. If you have a bad head you should see large amount of steam coming from the exhaust pipe. I would bet that the heater core is bad and the water is leaking out through the drain and that is why you aren't seeing any coolant. Check the heater core and see what happens if everything else comes out ok.

[Chris_topher23]

i agree, im guessin its the heater core