I have a 92 camaro rs and the cooling fan turns on at about 250!
I have replaced the thermostat, temp sensor, temp sending unit, and the temp gauge(with a another used one), and the problem persists. The radiator doesn't boil over into the reservoir when the gauge reads 250-260. Mechanics have told me the fans turns on at 228 degrees, but that the gauge reads a different temperature, about 25-30 degrees more. I appreciate any input. Thanks.

 

the fans on these cars turn on hot, i think its over 230 degrees or something like that. You can get a lower temp fan switch to lower it to something more reasonable like 190 or 210 from Jet or hypertech, ect

the factory temp gauge is not very accurate, its for reference only.

 

Your temp gauge is most likely really inaccurate. I have the same problem; my fan turns on when the gauge reads 260, but its actually turning on at 227 which is when its suppose to. Ive verified this with my laptop, and you could do the same or take it to a shop and have them hook up a scan tool to it.

 

So does the gauge itself create the inaccuracy, or is it the sensor. Is the coolant temp sens more accurate than the sensor for the gauge? Thanks in advance. (Sorry for stealing the thread)

 

Id never let my engine run over 200

Though there is a fine line between performance and parts wear.

185-190 is the best of both worlds.

Ill dig up the site that has the test info,

 

200-210 is perfect 4 gas milage, under 200 gas milages sucks

 

If you got the single fan set-up, I think it is controlled by the cooling fan switch in the pass. side head between #6 and 8 spark plugs. The temp sensor tells the ecm what the engine temp is and the sending unit tells the gauge what the temp is. I dont think you said that you tried to replace the cooling fan switch. Might be something to try.

 

I don't know, but if I had to guess I'd probably say the gauge creates the inaccuracy.

 

I have an 86 IROC and the gauge has never been accurate. Come to think of it, the only gauge that is accurate on my dash is the fuel gauge and speedometer. Battery guage is 2 volts under what is supposed to be, Oil is 5 psi off, temp is 30-35 degrees cooler than what guage says and tach, well we wont go there, that thing is way off.