i have heard most electric fans dont work as well on these trucks, but id there a electric fan kit that will work well? cause honestly that metal one kinda scares me.

 

All I've read is that you can't make them work, so of course that makes me want to try! I have two 14" 2400cfm units and I'm building my own shroud. It has 4 big vents that will open at freeway speed to let more air flow through. Without the vents and with the fans off, the fan blades will block the airflow and then things get hotter. Turning the fans on will bring the temp back down, but with the vents I hope to not need the fans while going down the highway. It will be an experiment, if it doesn't work it's back to the stocker. Or bigger fans!

 

i like the vent idea. maby stuff some big squirrel cage fans in there.

 

Every one used to tell me I couldn't cool my pumped up 390 with an electric. 18" single that blows like a *****. Keeps it cool in rush hour city, moving a couple of blocks in 15 minutes at 98deg weather.

I used to cool my 440 mopar with an 18" single too, never had an issue.

 

I tried Flexlite electric fans on mine, a pair of them.
Cost was about 100 dollars each.

They did a fine job cooling the engine, but where I ran into trouble was the amount of electric they used and the amount of time they lasted.

I am running a 150 amp alternator which was great in the summer.
But in the winter when I am plowing snow, the fans and the lights and the snow plow together just sucked the batteries down in no time.
I actually used the fans more in the winter plowing snow than I did in the summer.
Even though it was cold, driving slow and the constant load on the engine raised the coolant temp rather fast.
Summer driving at normal speeds, even with a load on the truck, the air flow was enough to keep the engine cool except on hard pulls.

I also found the composite material the fan was made out of got brittle and the fan blades would break off after about a year of service.
The motor also failed in one or two fans.

After 2 years, I looked at the increase in fuel mileage, figured what the extra power the engine had was worth to me and compared it to the cost of the fans.

I am now running a stock fan again.

 

I replaced my 90 amp alternator with a 75 amp alternator. How big does the alternator need to be? I have a 1987 6.9 with an electric heater for running vegi oil.

 

For what your running minimum would be 100amp. The amp rating is what it's maximum output is but only at short periods of time. So if your pushing it to it's maximum output all the time it will smoke the altenator quick. The bigger they are the less work they do longer they last.

There are many configurations some push some big amperage and even at idle when specially designed. Friend of mine has a business that rebuilds all sorts of stuff altenators, generators, starters, inverters etc. He does a nice job and is more interested in not having the equipment come back because it won't hold up to the work load.

 

I don't have much faith in electric fans either. The most efficient, cost effective way to do it is the factory unit. Unless the fan clutch is engaged, it isn't robbing any power anyway. Those electric units are pricey and they don't last long. The only negative is the weight of the whole setup on the rather tiny water pump shaft. Just keep an eye on the water pump bearing for play and all is well.

 

I got a used one I used on my 440 car that is off of a GM, I think it was a Caddy. Big fan and pulls a lot of air. Probably comparable to a $100+ aftermarket unit. Got it at a pick and pull for $6, wasn't sure how long it would last so I got another one. That was 8 years ago, haven't touched it.

I think if you are not running like Dave does it might be worth it, but obviously wasn't a good deal for him.

I have a spare big fan here and a pair of pusher fans, I think I might throw em on and see how they will work for me.

Hows that fan mount anyway. Does it just screw on in the middle?

What kind of fuel mileage do you figure it gave you dave?

 

It has been several years since I tried that.
As I remember my mileage increased a little over 1 MPG.

The stock fan clutch screws on the water pump shaft, left hand threads.
I also recommend a drop of Lock Tite on the threads before you install it.

I looked at a couple fans at NAPA, they did have one big enough to cool a diesel.
But the price was over 300 dollars.
After my experience with the Flexlite fans I was not willing to gamble 300 dollars.

I will also say that I have run fans on the big rigs that were driver controllable.
But that setup is a lot different than what we have.
The fan has it's own shaft, separate from the water pump.
The fan was set up with a Horton air clutch.
I wish I could have a setup like that on my IDI.

 

Just threw on my pair of pushers in front of the condenser. Had to cut the vertical support in the middle for clearance and grind some of the grille but fit pretty nicely. Going to make a wrench for the fan at work tomorrow. Going to throw on my big fan next weekend. Need to get a thermostat switch to control it.

Going to hook the pushers to the A/C pump so they cycle when it does with a second relay so I can control it manually also. Sure like the way it works with the A/C. Sitting in my driveway idling with vent temps of 38deg.

The other fan will get the thermostatically controlled switch with a manual override also.

So, What temp switch should I use to install in the bottom of the rad?
I can fab up a fitting to install in the hose for a temp switch so I don't have to mess with the rad.

 

72f2504x4390 are you talking about an electric fan clutch? If so where did ya get it i've been wanting to do that myself.

 

He is talking about electric fans....I have been looking for an electric clutch setup myself.

The big problem with that though is the water pump still has to turn.

I have seen a switch that has a temp probe that clamps on the upper radiator hose, has an adjustable thermostat, and a switch to turn an electric fan on and off.

I think it was made by FlexLite for their electric fans.

 

Yep I have seen that one. Flexlite makes it for sure. I am going to fab a tube to put inline in the lower rad hose and put a fitting in to use a screw in thermostat. Think I am going to try a 185 on 170 off. Maybe I should get a 200/180 too. They are only about $25. Want to keep it in the lower end of the system so it is measuring the outlet temp, not inlet temp.