Accessory fan coolant switch

[FORSFED]

Ok, I finally picked up an accessory fan harness at the junk yard yesterday and I wired up my SPAL fan to the factory harness. Now my question is at what temp is the switch supposed to turn the fan on??? I warmed up my car and let the coolant get up to just 220* on my Autometer gauge and the fan still hadn't turned on so I'm wondering if my switch in the radiator is bad or if I'm just missing something...

[brently]

I run my slim fan off a toggle switch inside. Simple and Easy. Run it full time durning stop and go traffic, and turn it off when doing those hwy pulls, or any freeway driving. Just keep your eyes on your gauge. BTW. 220* is pretty hot. try to keep it around 180*

[FORSFED]

220 isn't too hot, many gm cars I know of run 210 - 220 from the factory as well as my girlfriends blazer that stays at 220 all day long. My car normally runs 185 - 190 while constantly moving but rises quickly when stopping and going frequently. I had two slim fans hooked up to a toggle inside the car, but I don't like this because on two occassions I've caught myself turning the fans on late when the car is creeping up to 225 - 230. I'll leave my smaller one toggled, but by hooking the large fan to the factory sensor would eliminate having to worry about switching fans on all the time when the car gets warm. Anyway, does anyone care to elaborate on my original question...

[A//// Guy]

210 and higher is getting pretty hot on our cars. Its not very good for the engine to run so hot. Either your thermostat is not opening all the way or something else is wrong (rating)? My car without a fmic sat at about 196 all year round, but I put the FMIC and cruising around with 1 stock fan it went up to about 206 to 210 without AC running.

I would use some water/waterwetter mix and lower the temps a bit. Your oil must be uber hot at 230 water temps.

[brently]

220 isn't too hot, many gm cars I know of run 210 - 220 from the factory as well as my girlfriends blazer that stays at 220 all day long.

on cast iron heads

220* on a aluminum head is just asking for a warping. NOT saying it will, but its not good. Ive gone up to 240 before and I thought it was all over for my poor ported head, thank god it wasnt.

[FORSFED]

Ok you've got a point there, I wasn't thinking alum vs cast. But my car does stay relatively cool at 185 - 190 as I stated before. I'm not trying to solve an overheating problem, just simply trying to figure out when the temp sensor is supposed to turn on so I know if mine is bad or not. I'd like the fan to turn on automatically instead of me forgetting about it one too many times and f***ing up my car.

[brently]

Ok you've got a point there, I wasn't thinking alum vs cast. But my car does stay relatively cool at 185 - 190 as I stated before. I'm not trying to solve an overheating problem, just simply trying to figure out when the temp sensor is supposed to turn on so I know if mine is bad or not. I'd like the fan to turn on automatically instead of me forgetting about it one too many times and f***ing up my car.

I believe the coolant switch is the sensor on top of the housing, above the thermostat, facing the exhaust manny. check the wires coming out of it, there usually fried from being so close to the exhaust manny.

[brently]

I believe the coolant switch is the sensor on top of the housing, above the thermostat, facing the exhaust manny. check the wires coming out of it, there usually fried from being so close to the exhaust manny.

EDIT: didnt read close enough. Im not sure when there supposed to turn on. I think they turn on after the t-stat opens up, and turns the cooling system into a completed loop. OEM stats open up at 180?? maybe.

[Swifty1638]

Man, I turn mine on every time I get in the car, before I even start it up. the toggle also has a red led in the tip, so I don't forget to turn it off. I even have my fuel pump off of a covere-d toggle, for added security..only blows when I gotta leave it on for the auto-start..

-A. Swift

[LightningGSX]

The fan switch is on the lower corner of the radiator itself, it should turn the fan on at 185 F