lemme post the arsehole remark.. i've seen it happen..

The brass plug of the thermostat goes INTO the engine block.. if you can see the brass plug.. the thermostat is in backwards..

now that that is out of the way.. check to see if your rad is getting hot..

if it's barely warm.. and it's overheating, your waterpump is dead OR you have an airlock somewhere in the block/head.

take the thermostat out completely.. that will eliminate it as a problem.

-- WheatKing