cooling system

hi, the problem im looking for help with is this. my camaro which runs fine but my cooling fan will not come on until just about in the red warning area. then it comes on and all is fine.like i say it runs fine but if one time it decides to fail ive got no warning and will be overheating. actually while getting my e test(from canada) it did overheat. ive replaced the whole cooling system got lowest thermostat possible and still does this, cannot figure it out have had it to probably 10 different guys and still they are stumped, all sensors and relays everything has been checked , will appreciate any input or suggestions. is very concerning when mid summer stuck in traffic and just waiting for fan to go on and just pray that it comes on.

also it is a 91 rs 305 throttle body

try the temperature sensor for the fan. its LIKE a thermostat, but it just measures the temp of coolant, to activate the fan, and if thats blown, it doesnt matter what you replace, that fan will not kick on if that sensor is broken.....


OR


you can do what i did once on my dads old car, just get a 50 cent switch and run wire to a switch and manually activate the fan, kinda ghetto but it will keep the car running nice and cool

not sure what year camaro you have but in 4th gen if you turn on the defrost or the AC it turns on the cooling fan also. i discovered this by accident, i was sitting out front of somewhere waiting for like 25 mins for someone to come outside when my windshield kept fogging up so i left the defrost on about middle temp and middle fan speed and the engine got to the coolest point it could run at in about 6 mins. pretty cool, robs horsepower tho while your driving.

also, that lower degree thermostat you have aint worth a damn unless your computer is programmed for it.

ya i also have a 91 rs tbi and mine does the same thing. but when my gets between the 220 and the 260 on the temp gauge i do what LT1 does. so that does work with the third gens also. i know it sounds stupid but check the level of the coolant in the radiator. if mine is real low then none of the sensors work for some reason and i have to turn on my fan by turning on my ac. Im not sure if it will work, but what im thinking about doing is bying one of those fan switched from jegs or summitt that turn on your fan at a lower temp.