I've been thinking about going the Electric fan route... My instructor in Diesel School has a 98 dodge and said he took the fan off his truck for the summer and he got much better mpg. He said he was getting 18 then it jumped up to 21 without the fan. He said he couldn't tell a difference driving it but it got better mpg. My Friend also has a 98 12 valve swapped into a 2000 ford, right now he is running no engine fan cuz of fitment issues, it has been fine all summer til he towed my truck to a pull up a canyon and it overheated then. Once we got coasting down the other side of the canyon and got airflow going through it again it cooled right down, he has electric fans he is gonna put on for situations like that, but for the most party do we even need our engine fan??? unless its on a hot day, going slow, or towing I don't see why there would be an issue taking off the power robbing fan. I'm thinkin about takin mine off for the winter since I want my truck to warm up faster anyway, then maybe fitting some some Electric fans on next summer if I really need them.

Whats your thoughts on this and has anyone else seen a mpg or hp difference by taking their fan off? Also what CFM would a stock fan go? and how big of electric fans would I need if i did go this route? I was thinkin of runnin two side by side, but I need to go measure my radiator...

 

with an auto trans you are going to get HOT with no fan. Also if you have a/c it is going to be very unhappy with no air flow over the condenser when stopped.

I have an electric on mine and when it is hot out and pulling my jeep up the side of a mountain it still gets pretty warm but seems to recover ok.

My fan is a oem 2-speed ford fan from a taurus. There is a lot of info out there from people using these things is pretty much anything with 4 wheels and an engine.





It is a tight fit in there.

 

I picked up 2mpg on my 97.....unless it was up a grade, the fans never came on.

 

I've got a bigger B&M trans cooler with a fan under the battery tray so it cools my auto just fine and I don't use my AC that much so that won't be a problem especially in the winter. You can get the universal fans or kits on ebay for pretty cheap, with the relay, temp switch and all. I was thinkin about goin that route with two decent sized fans, I figured they wouldn't come on too often just cruising down the road.

My instructor said that he had a jeep with a hydraulic powered fan powered by the power steering pump, he said this way the fan wouldn't use any power at all since the motor has to drive that anyway. Said they only came on 2 years or something though and don't know why anyone else has gone to that.

 

If it had a fan from factory it was there for a reason.

 

https://www.dieseltruckresource.com/...-t54116p2.html

 

I had a Taurus fan on my truck and it worked ok but I didn't notice any mileage increase. You will need a big fan not a little eBay cheapy. It don't take much to cool our trucks but once it starts to get warm it is hard to stop it from getting hot. If you still have the stock trans warmer on the side of the engine hooked up that will help it get hot also. The trans fluid will get hot and the coolant will suck up that heat. I took mine off because I had electrical issues with my fan circuit because the fan draws so much amperage. It wasn't worth the aggravation.

 

You need a fan for slow speeds and high boost situations.
I really don't believe the claims of big number improvements with no fan or electric fans.

When i pull heavy, above 10,000 lbs, the fan will engage at speed when accelerating.
This is the only time i ever hear it.
I had an old bread truck with the 4bt and manual trans. This truck never got over the thermostat temp---EVER!
And it ran in town and highway with a GVW of 11,000 lbs.

 

I tried running my old 2wd auto without a fan one time. on the highway no A/C it got hot with ambient temp ~65deg.

I don't see how you can run without any fan at all. With no towing I could see you getting away with a decent electric fan.

 

Electric Fans and no towing are good. Any heavy towing will get you hot.

 

I bought my truck with a small electric fan. I turned it off and the temp gauge never went higher than a tick past the normal mark. Once I knew that, I set it to just come on at that point.

It might help mpgs...

I have a 5spd, 33x12.5x16.5, 4.10s, at 2000rpms (67-70mph), I got 23 mpgs...

 

Im thinking im gonna pull mine off for winter then rig up some dual fans for next summer, if it still has heating issues then it wont be too hard to throw the stock fan back in.

How much cfm does the stock fan push, anyone know? Or what size electric fan or fans do most of ya go with? I was thinking on a dual fan setup.

Also what size is the nut on fan? I heard it was like a 32m or somethin and is it reverse thread?

 

I had a 2000 that I took the fan off for the winter, it was the only way to get any warmth in that truck. I used a pneumatic hammer to take it off. Yes, its a reverse thread and the hammer was the only way to get it to budge. When ever I towed, things got toasty and I had to use the heater fan to try and keep things a cool (sometimes it worked, sometimes it did not).

The stock fan will pull 8,800 CFM at full lock, the best aftermarket electric fans I could find pulls 5,500 cfm. If you're towing less than 18,000 GCVW, the 5,500 CFM fans will work, but if you tow heavy, keep it stock, Cummins put that big propeller on the front of that motor for a reason.

 

Stock fan nut is 33MM I believe and LEFT-HAND.


Everyone is always trying to put a CFM value on the stock clutch-driven fan.

I see no accurate reliable way to even get a close estimate of the true down-the-road CFM that a hardly-ever-actually-engaged clutch-driven fan is gonna pull.


The big advantage of decent electric fans is that they are fully engaged at full speed at all times that they have electrical current.

I would not hesitate to tow anything with good electric fans that can be towed with a clutch-driven fan.


I am gonna go the electric route whenever I can get time and money ahead to do so.


Currently, on my personal truck, I am running a direct-drive fan-hub, Flex-a-lite #852 and a six-blade steel Flex-a-lite heavy-duty truck fan, 19" I think.


I cannot feel or tell any difference in power or fuel mileage without any fan at all, with a stock clutch-fan, with a pinned stock fan, or with this solid hub direct-drive fan.

 

I forgot to also say that a clutch-driven fan never fully engages.

There are three separate stages of fan-clutch; something like regular-duty, heavy-duty, and severe-duty.

A severe-duty fan-clutch will only spin the fan at about 80% of fan-pulley RPM at full engagement; this is with a brand-new quality unit, which I have yet to actually see; not saying that there aren't a few out there, but that I have had no good experiences with fan-clutches.

There is always a measure of viscous slippage.

Add in a few thousand miles of wear and tear and that 80% engagement is lucky to be 40%.