ive got an 83 trans am 305 4bbl with a clutch fan starts out fine but after about 10 or 20 mins of driving its hit around 240* 250* then after its been there for a min or 2 it slowly falls to 220*230* and stays there till i turn it off the water pumps been replaced the thermostats still stock the air dam is still there and where its supposed to be mostly any help to make i run under 200* would be great thanks steven

 

If it's happening while the car is moving then it's not the fan's fault. Are you sure your temperature gauge is correct? have you tried another thermostat?

 

yeah changin the thermestat helped sorry for posting before i tried it