Cooling Fan not working

My saturn is running hot after 10 miles of driving and the water completely empties from the overflow tank. I am unable to get to the radiator. I have changed the thermostat, water pump and there are no leaks, but somehow the water is always gone. The mechanic has checked all hoses and heads but still the car runs hot. Help please.

I also have a 2000 Saturn SL2 with the Twin Cam 16 valve engine. It's had a problem with overheating. The cooling fan doesn't come unless the air condition is on. We checked the cooling temp sensor, the car only has one, and the temp gauge works fine so I assume the sensor is fine as well. The coolant also disappears somewhere. We've changed the water pump, thermostat, and checked all the hoses. Water does seem to be leaking from the rear of the engine. Can you please help?

You said the intake manifold gasket is common to leak; would that cause bad compression? Because the car has been running real rough and cutting out. I checked compression in cylinder four and it was low.

The car also seems to be burning oil. Have to add a quart every now and again. Could all of this be the same problem?

I've had my 2002 Saturn for about 7 years now and I'm the second owner (only 7,000 miles on it when I got it).
There was a problem with the AC clutch which I had replaced about two years ago, but then about a year ago the same problem occurred. Not having the $700 to get it fixed, I've been driving "as-is" with no problems. I'm not sure if that's related to what I'm about to tell you.
About 3 weeks ago, my "Low Coolant" light has been coming on every time I start my car. It eventually got to the point where I was putting antifreeze and/or water in every day. I took it in to a mechanic and they couldn't find a leak, so they put some stop leak in it and said to come back if the problem continued. It did. The light kept coming on and I had to keep filling it with water. A few days later I was on the highway and my car began to overheat, by the time I got off an exit and to a gas station it was red lining. I waited for it to cool down and then filled it back up with water. 3 miles down the highway and it overheated again. Bone dry. I filled it up again & dropped it off at the mechanic.
They said that the water would overheat & bubble out of the reservoir. They replaced the water pump and returned it. It was fine for a day, but then after starting the car, the coolant light came on, and when I stopped, antifreeze was dripping out.
Back to the mechanic, they replaced the thermostat and radiator and I got it back.
On the way to work today, it overheated again.
What else could the problem be?

You could still very well have a leak and your radiator fan could be bad. (As mentioned in previous post) If you take your car back in to get your car checked again. Make sure that whatever shop you take it into uses a Coolant system pressure tester. Because small leaks are next to impossible to find without it. What that does is it presurizes your entire coolant system simulating the pressure it builds when the car heats up and checks to see if it maintains the recomended pressure. They can also check to see if your radiator cap and/or resivor cap as well. Giving you a more accurate diagnosis.

I forgot the exact number it's been a few months ago, we haven't driven the car since, I know it was about 5-10 under.

It would usually burn about a quart or two every 2,000 miles.

Finally got it fixed (after a month in the shop)

Your right about the fan not coming on. One of the times I took it in, they suggested having the a/c on at all time to trigger the coolant fan to run, as well. That didn't work, though.

They took the engine apart and found that the problem was a warped head gasket.

Prior to this, the water pump, thermostat, and radiator have been replaced.

The car runs perfect now.

Thanks for your input!