My thinking is that I should place it so it measures the radiator output temp, and set the trigger temp lower. This way if I'm driving fast enough for the ram air to cool the engine, the fans won't come on. As soon as water starts getting through the radiator without getting cooled, the fans would come on. If I put the sensor on the radiator inlet, the fans would come on whenever the engine was putting out hot water, even if I was going fast.
Is this sound logic? It's a dual pass radiator, so I also have the option of halfway through the radiator.
Full Version: Electric fan thermostat sensor location
If you put the sensor at the exit, then your fans will cycle alot. Imagine this, the radiator isn't quite cooling enough, so the fans will kick on, which will cool the fluid in the radiator, which will then pass the temp sensor, and turn off the fans. They will go on and off repeatedly.
Better to stick the sensor before the inlet and set the turn-on temperature higher.
Demick
Better to stick the sensor before the inlet and set the turn-on temperature higher.
Demick
QUOTE(Demick @ Apr 25 2006, 09:13 AM) 
If you put the sensor at the exit, then your fans will cycle alot. Imagine this, the radiator isn't quite cooling enough, so the fans will kick on, which will cool the fluid in the radiator, which will then pass the temp sensor, and turn off the fans. They will go on and off repeatedly.
Better to stick the sensor before the inlet and set the turn-on temperature higher.
Demick
Hmm, good point. I would prefer some cycling over running all the time, but I wouldn't want cycling every few seconds. Perhaps midway through the radiator would be a good compromise. Maybe I'll put a couple different ports on it for the temp sensor, and try different locations.
My temp gage reads engine jacket temperature. I have one fan on an adjustable temp sensor and I set the fan to come on at 190 engine temp (180 tstat) it seems to work fine. The second fan I have on a manual switch since the single fan seems to do the job fine. There might be a hot day in traffic when I'll have to manually turn on the second fan. The automatic one runs for one minute after shutting down the engine. The thing I notice is the lack of circulation at an idle. If I was to work on the system again, I'd put in a small electric pump to take care of that.
QUOTE(tyler @ Apr 26 2006, 01:31 PM)
My temp gage reads engine jacket temperature. I have one fan on an adjustable temp sensor and I set the fan to come on at 190 engine temp (180 tstat) it seems to work fine. The second fan I have on a manual switch since the single fan seems to do the job fine. There might be a hot day in traffic when I'll have to manually turn on the second fan. The automatic one runs for one minute after shutting down the engine. The thing I notice is the lack of circulation at an idle. If I was to work on the system again, I'd put in a small electric pump to take care of that.
My water pump is electric, so I'm actually going to have it set up such that the fan AND the pump run after the car shuts off. I've decided to just do it demick's way and err on the safe side. I'd rather have the fans on more often than necessary than to possibly miss the chance to cool water that needs it.
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