All this talk about cooling. I've been considering converting the Dak to electric fan for a long time. The manual clutch fan gets loud when the AC is running and I'm sure it robs the power. I say "electric fan only" in the title, because this 4.7L with tow package already has an electric fan, which faces the clutch fan (heavy duty cooling). Pic below is with the shroud removed. So I'd be replacing two fans with one.

One challenge I can see is the stabilizer bar which crosses over the radiator in an upside down "V". It would interfere with an aftermarket (or Lincoln Mark 8) fan shroud. Now the truck is super reliable and never overheats (at least thru no fault of it's own)... https://dodgeforum.com/forum/2nd-gen...the-4-7-a.html... so I'm wondering if I should just leave things be. We all know the 4.7L doesn't take well to overheats. I really don't want to fuss with this too much, so if someone has already done this with this particular setup, I'm all ears.

For convenience, gonna start compiling my info here

My rad:
https://www.carparts.com/radiator/csf/csf3516
CSF 3516 Aluminum Core Plastic Tank Radiator, 23.5 x 18.81 x 1.63 in. Core Size (I measured 23.25 wide)

The mark VIII fan assembly is...
21.75 wide x 19 high x 5.75 deep.

Factory clutch fan blade is 19.5" across

 

That bar really isn't all that substantial.... Wonder if removing it would cause issues......

 

Just a radiator support brace, might cause a bit of front end vibe. Might be able to extend it with longer bolts or something.

 

Removing it probably would not cause any issues, my truck (2003 3.9L) didn't even have it although that's not to say it never had one since I'm not the original owner. Plus that upper rad support cross bar is pretty hefty on its own, and bolts in with large bolts on either side. But if it's a concern another bar could be made that goes around the fan shroud, or it could be moved to the front of the support. But, considering the OEMs don't add excess stuff if they can avoid it because it costs money to do so, there may be a legitimate reason for having it on there.

A word of caution, the Ford fans have a screwed up method of operation and those fans require a specific controller to operate. They put a tap in the middle of the motor winding for low speed operation, and a tap on the end of the motor operation for high speed operation. If your controller isn't set up to only put power to one or the other, never both at the same time, it'll burn up the fan motor. Delta Current Control makes a Ford-fan specific controller that works for the Ford fans. I've used their controller to run a pair of non-Ford fans back in 2000, and it worked great on the pair of Perma-Cools I used them with. These days I use the factory ECM for fan control but if I were doing another car that didn't have fan control in the ECM Delta is who I'd go with. If you go with non-Ford fans I've attached a diagram showing how GM wires up their dual fans, so that both fans are wired in series for low speed and in parallel for high speed, which keeps the noise down unless it really needs the airflow. If you are using temp sensors instead of a computer, you'd need two of them with about 15-20 degrees between them, and they would need to be the sort that close when their set temp is reached so as to ground the relays. Connect the sensors in place of the computer high/low speed taps with the higher temp sender on the high speed tap.

 

I'm in the be safe club no change especially if your looking for a little Hp boost as your gain would not amount to much of nothing especially when you did have a small head gasket leak you fixed and at 300K miles.

Try a compression test see if she is still in the good healthy range that may be a good start.

 

Respect all the opinions here. Thanks for the controller info, Vimes. You said you are controlling your fan with the ECM, mind sharing how you set that up?

98DakAz, I'm not fully committed to this yet. For one, I thought I'd easily find the Ford fan in one of the many junkyards here and that wasn't the case. Looks like they are in hot demand all over. Secondly, I think I'll keep the factory e-fan in the pic and fashion some type of deep shroud to mount the new fan. Ideally, I'd like to keep the OEM combo shroud but I don't know how possible that is. It's not like I can mount anything directly to it.

 

I'm not recommending this but. I ordered a 2003 4.7 5 speed CC with towing package and 3.92 gears back in 2002. At that time one mod was to just remove the clutch fan and use the factory electric. I took the clutch fan off on day 2 of ownership. The truck has 380 000km now, I know the 2nd owner.
Its also had the jeep HO cams since 13000km and I did not do valve springs. The engine has never been apart and never had a clutch. I did its first oil change at 500km and 5000km after that. Since I knew they were having overheat and head gasket problems I did a coolant flush and thermostat at 5 years. It did get a rad at 7 years as it blew it up so I also did rad cap. I used it as my tow vehicle. I raced 5-10 times a summer. The temp would get a little warm towing on long steep hills as I would run full throttle up them. Other than that no issue with cooling.
I was not easy on that truck and I'm surprised its still going as so many 4.7's have problems.

 

I have seen mention of this before. I don’t know that I have the courage to try that, tbh. Having a manual tranny may have helped you as it poses less of a cooling load. I have an ATF cooler sitting in front of the condenser. I’m now over 322,000 miles and I’d like to keep it going, LOL. Interesting idea tho. Maybe something to try in the winter.

 

Heh heh, using a GM computer, in a couple of Chevy Silverados and a Chevy Colorado. I posted the diagram to show how you could control a pair of fans in a series/parallel operating scheme in the same manner GM does it. The GM method runs both fans at half speed on low and both fans at full speed on high. I don't know if the Gen2 Dak ECMs even have a means to control electric fans. If not, then what you'd do is get a couple of temperature operated fan switches that sets a ground when the correct temperature is reached. Get one for, say, 185 degrees and another for 200 degrees, then wire the 185 in as though it were the low speed, and the 200 as though it were the high speed. I whipped up another diagram to show how to use the GM control scheme without a computer. This will be less efficient than an ECM-controlled setup though, because it'll run the fans on the highway when the air conditioner is on. The ECM would only run the fans at highway speeds if the AC high pressure switch trips.

On the temperature operated fan switches, they would need to supply a ground when the set temperature is reached, and would need to be screwed into the engine block somewhere in the water jacket. You'd have to determine where to do that on your own. You could also cut into the engine inlet rubber water line and put a short metal sleeve in with two senders screwed into it provided you ground the metal sleeve. Wouldn't be the prettiest thing to look at, but would be very effective.


Before actually doing all this though, I'd use a DCC heavy duty twin fan controller. Much simpler, very effective, and it soft starts the fans where the above would slam your electrical system over and over. And really, you'd not be saving much over the DCC system by the time you bought the relays and all, and took your time into account.

 

Thanks, Vimes!