HELP!!! fans, thermostat, and radiator.

[perkysmiles]

[color=blue][i]Several problems with monte so far. Fans only work when the AC is on. Temperature guage stays normal when the coolant is boiling out. Radiator seems to be clogged. And I am really hoping that the heads arent blown its been chugging through water and coolant like it's never had a drink in it's life. So I am also thinking the thermostat has gone bad. And to to top it off the break left break light works only when it feels like it. Checked fuses and changed bulbs as far as fan and breaks go. Read a forum that says it's probably the turn signal switch over riding the break light. Going to change the thermostat tomorrow but the radiator I'm sure needs replaced considering some oaf thought it would be cool to try and fix it with something akin to silicone and clogged one side of it. Any ideas on the fan or diagnosing these troubles would be greatly appreciated.

[84'MC350]

If your car comes with the belt driven fans they come equiped with thermal clutch on the fan. They don't work as well when they're old. To see if you have a bad clutch turn the fan blades manually and note the resistance. Then turn the car on for 2 minutes. Stay aware of your car temp guage then turn the car off. And then manually turn the fan blades again. There should be moderate resistance depending on the temperature. If you note that there isn't more resistance as it heats up than thats your bug. Hope this helps