Finished wiring a 16" Derale electric fan onto the radiator to replace the yellow clutch fan a few weeks ago. I wired it to a non-switched source. Originally, it came with a 180F on and 165F off NPT switch that I put in the NPT that was vacated when I removed the air pump stuff - A bank, rear. I have a battery kill switch in the trunk, so if I think the fan runs too long I can manually kill it, which is why I wired to the non-switched.
With that low of a shut-off and on a non-switched source, the fan ran forever and never shutoff - well at least in the 10 minutes I allowed it to kill the battery. At 180F it comes on even before the smaller, original aux fan.
I next tried a 200F on and 185F off thermostat switch, thinking that would be a better solution. Comes on after the aux fan, but still ran at least 30 minutes after the car is shut-off.
I ran infrared temperature checks as best I could and the temp after about 2 minutes of the car off and the fan still blowing, read from 186 down to 172 - which shoulda cut the temp off.
I’ve got more diagnostics to do to figure out, but the first one I thought about was maybe the temperature really does stay about 185 for a long time where I have the probe positioned on the A bank.
Pics first, then any thoughts would be greatly appreciated!
The problem is not the switch but it’s location.
As it’s mounted on the water rail it will stay hot for ever, there is a lot of residual heat and the switch will not turn off until the entire block cools down, and is taking a very long time to do so.
Either you connect the fan to a switched source, either you mount the switch somewhere on the the radiator. You could even use the existing switch for the Aux fan.
I also see that there is a huge gap between the fan and the shroud.
You should close that because this way the fan is just recirculating hot air from the engine compartment.
I bought a Derale 16769 adjustable fan controller for my car, wired in parallel with the temp. switch for the aux. fan, and placed the probe under the hood so that it responds to air temperature, not coolant temp. This helps deal with the heat-soak underhood temps, but the possibilities are endless.
This seems to be the case, however, the new fan with its own shroud is positioned in the old shroud (now defunct). This can actually be taken off, I guess.
While I am a fan of electrical fans (lol), we seem to underestimate the air flow of the original fan and replace with less capacity versions ones. Bear that in mind.
I’ll probably look at fabricating a seal, but as it stands, the fan produces as much if not more good air flow over the motor as the clutch driven fan. It’s rated at a little over 2100 CFM.
I think I’ll look at wiring to the aux fan first. That open NPT port was just too good to be true - so easy to access and just begging to be used. I wonder if I can put it to use for something, maybe a gauge to measure the high coolant temperature.
If you still have the thermal valve you removed from the port you like you could use it again to make an adjustable fast idle scheme for when the engine is cold. (Depends on how well your AAV works.)
. I totally got myself confused. I like the idea of having the adjustable cold idle. I actually cleaned and tested the AAV and it’s operating great. I removed the air pump, not the AAV, doooh.