I found something interesting regarding engine temperature and an e-fan yesterday. Apparently, I've had my E-Fan hooked up wrong since I installed it late last year. The only way the fan would run is with the air conditioning. The regular temperature sensor by itself would never turn it on. I don't know what the hell i was thinking when i hooked it up like this, I'm baffled I ever let myself do it.

However, what I also leaned was that the 4.0 will keep itself cool quite nicely on it's own without any help. It was 100 degrees on monday and tuesday. I was driving around without the AC on (windows down) which meant NO FAN all day. The temperature remained in the middle for the entire time. The only time it starts to clim is when it's idling for more than a few minutes. Stop and go traffic wasn't even issue.

I think next I am going to experiment with disabling the fan to see if the AC works without it while moving on the highway. I could save myself some amps by making it not run when not needed.

The story behind me figuring this out:

I had my truck idling for a while outside my friend's apartment while unloading a trailer of furniture on Tuesday night. It was sitting for maybe 20 minutes at idle. The AC was turned off. After about 20 minutes, my friend yells to me "Hey matt, your truck is smoking!" The expansion tank was boiling and the temp gauge was pegged. I started following wires to see why the fan wasn't turning on and found my error. As soon as I got the fan turning, the temperature dropped right back to normal. Poured some water in, good to go. Now I need to re-wire the fan controller so it works properly.

 

the reason your engine stayed cool is because there was air moving through it when you were moving....you didn't sit long enough to get a temp rise.........make sure you fix that problem so you dont have more problems from overheating.

 

lol, ya it does do a pretty good job cooling.

as for the a/c on the highway, after 30-40 mph i dont use my efan when the a/c is on and it works perfect.

 

cool story. heh I wonder if any other threads regarding e-fan installs are going to pop up

What wire exactly was the cause of the problem?

 

I know. But I never realized that it kept itself that cool so easily. Even stop-and-go traffic and idling for periods of time less than 15-20 minutes were not causing an over-heat.

I hooked the AC input up to the AC clutch wire. This should be hooked up to the purple AC demand wire in the cab, but thats another unrelated project. The problem was I hooked the ignition wire up in the power distrobution box to a point that only gets power when the AC is on... not when the ignition is on. So the fan would ONLY run when the AC was on. Stupid me.

 

lol....i am going to take my a/c wire that is hooked up to the purple wire and put a switch in it to disconnect it when running down the interstate with the fan on....an interruptor switch so it wont get signal anymore......

 

a few days ago i was messing with the temp switch on my e-fan. No matter what i set it at the temp gauge would only go about half way. I was starting to think there was something wrong with my controller. But then i realised that i was going about 35mph most of the time. This would probably keep it cool on it's own.

 

You know, this is a perfect opportunity for me to fix my AC mod switch too. I broke it over the winter so you have to poke what is left of it with your finger-nail to operate it. I'll replace it with a double pole/double throw switch that is wired as follows:

UP: AC on, Fan On
Center: AC & Fan Off
Down: AC on, Fan off.

The pole for the fan would be on it's own 12V power so even if the HVAC is off, I can put the switch to ON and manually engage the fan. This would be a nice backup if the temp sensor ever bites the dust. I'm not sure I can make this one switch also totally disable the fan, but I'm not sure that is neccessary for me anyway.

 

My race truck has an e-fan with just a switch to turn it on. It never gets turned on. Never.

I have heard of northern guys that flat out remove their stock fan in the winter months to save gas. They put it back on when it starts warming up.