Ok, i have a 91 Camaro RS that loves to run hot. I cant let the car sit for more than prolly 5 min otherwise it over heats. It would get up to 240 before the fan turned on. I put a K&N filter in it (open element), relocating the sensor (IAT) to just behind the filter and the fan didnt turn on..at all. The fan works because it comes on w/my ac, therefore the relay is good. So i put on the stock filter agian, puttin the IAT back in it, and it decided to turn the fan on again at 240, but it still shouldnt get that hot. I replaced the fan switch underneath the heads on the passanger side..so my question is..what the hell is goin wrong that it's over heating that much?

 

the temp. gauges in our cars are not the most reliable in the industry, most fans don't come on till around 220* anyway. so if your gauge is out a little bit it would appear to be running hot and really be running at what the factory designed (195* or so)

 

not a bad idea..not one im happy with,but not a bad idea..ne other ideas before i say phuk it and get it diagnosed somewhere?

 

I believe single fans will kick on at 238. So basically it is working correctly. Why not go to NAPA and get a cooler fan switch. The carry two different ones. They have the stock 238, and one that will kick the fan on at about 210-215. They run $19. If you opt for a Jet switch you'll pay about 40-50 bucks. They are no different in quality. As far as that IAT business is concerned I'll check it out. I didn't think it had any control over fan control at all. Just remember that a lower fan switch will cycle the fan more often shortening it's life and placing more stress on the vehicle electrical system. You will have decide what's best for you.

 

THanx danno..but still..isnt that hot for a chevy small block?..i thought they werent supposed to get above 220

 

That is always the big debate. Thermostats generally fully open at around 200 degrees(195 stat), the guage is not always fully accurate so knowing the actual operating temp is difficult. Don't forget where the guage sender is located. The actual temp of the coolant after heat is transferred by the radiator is probably lower than what the guage reflects. All modern engines, even my sportbike run at 195. This is primarily because of efficiency. Some people say it's emissions, but the more efficient the engine is running the less the pipe needs to be cleaned. You are not really in any danger until you head towards the 250 deg area. The main reason GM turns on the fans roughly 20 deg higher than operating temp is because they are fairly efficient at reducing coolant temp quickly and to keep them from constantly cycling. A single fan motor can pull as much as 18 amps when it starts. Dual fan setups twice that. Cycling the fans on and off constantly places undue stress on the fan motors shortening thier life, and also places a heavy load on the alternator. The engineers when they designed the car had all this in mind. If they were comfortable with this operating temp who am I to argue. As I have said many times, running a synthetic oil is probably more beneficial than messing around with stats and fan switches. Only my opinion, she's your Baby!

 

i sorta had the same prob. when i dropped my rebuilt engine in it would run at like 255 after driving for like 10 min...i couldnt figure out what was wrong and it was really irritating me, the whole cooling system had been replaced, i tried a 195, 180 and 160 stat still no difference, finally got a mechanical gauge hooked it up, took my stat out put the 195 in it, i drilled 3- 1/4" holes in the stat dropped it in, hooked my fans up to a toggle so there on whenever i want them to be...never sees 210 now, I think the biggest thing was the gauge as was mentioned before

 

I am assuming that you only have one single fan, correct? If so then there are two ways in which the fan will turn on. One is from the ac pressure switch (which you know is working). The other is by the ECM. If you want to test to make sure that the ECM output is working correctly (not fried) then there is an easy way to check it.

Simply jumper the A and B terminals on your ALDL connector (the same way you retrieve trouble codes) and then turn the key forward to the on position (you don't have to crank or start the engine). This will make the ECM turn the fan on. If it doesn't (and you know that you jumpered it correctly by the SES light flashing) then there is something wrong.

P.S.
There is no thermal switch in the head for a stock single fan set up, that is only for the secondary fan on a stock dual fan set up.

 

ok tuned port..thanx for the help but i hate to tell ya..ur wrong..i replaced the fan switch in my single fan set up under the head..unfortunately for me tho the "new one" was a dud..so i wasted 137 bucks today to have it diagnosed and a new one put in..thanx for the try tho

 

Well I'll be damned, those 5.0 tbi single fan cars do have a thermal switch as well. Guess you learn something new everyday!!!