My 99 super duty crew cab A/C does not cool the inside of the truck very well when sitting in stop and go traffic like I always do, in south Louisiana. I recently rebuilt the whole a/c system and it works great when I start rolling. I think my fan clutch is working correctly. I have been thinking about a way to convert to electric fans and take that huge weight off the water pump snout but I havent found a way to do it, that I like. I was wondering if anyone has installed a pusher fan in front of their a/c condenser that comes on with the a/c system. I would imagine it causing any problems while driving, seeing as a bunch of cars have pusher fans and I could only think it would help the cooling system. Im just curious if this has been done. I tried to search but didnt come up with much.

 

clutch fan working correctly?? it may not if over 6 years old. what about the blades. they can flatten out over time.

as for a pusher fan.. its done all the time. and KEEP the clutch fan.

what about the radiator shroud , is it in good shape.

what about the radiator.. are all the opening OPEN.. or has dirt/bugs plugged them up and reducing the air movement.?

if the AC system is 100 percent. no extra fans are needed. it worked correctly when NEW.

 

I wouldn't suggest mounting anything in front of the radiator. You may need all that airflow when towing in hot weather, and mounting a pusher fan would likely reduce the amount of air your cooling fan can suck through when fully engaged.

It would probably help during the stop-and-go conditions you mention, but I wouldn't risk an overheat when you need maximum cooling performance.

 

Alright, well I haven't thoroughly inspected the clutch fan. I know that it comes on and cools the truck, and I know the blades are straight and in good condition. The a/c system was just rebuilt. New compressor, condenser, dryer, evaporator, and orfice tube. The radiator is in great shape and was cleaned when the condenser was out. The coolant was also flushed and the old stuff was clean. Also, the fan shroud is intact and in great shape.

I think I might go ahead and install a new clutch fan just to be safe.

You really think the pusher would become a restriction? I feel like the fan would move more air than the truck would at highway speed. I might be thinking wrong though.

 

No
electric fan will slow down the air movement at freeway speeds. as the motor is in the way of air for radiator..


but at slow speeds it might help.


just like the clutch fan slips at freeway speeds... and hold tight at slow speeds.

 

I added twin electric puller fans on my 2000, leaving the stock mechanical fan in place. The electric fans are close coupled to the transmission cooler, and are mounted directly below the intercooler, in between the trans cooler and the radiator.

The electric fans are useful in slow speed, high load maneuvering, because the factory fan clutch thermostat can only determine when a temperature already has been reached before engaging the engine driven fan accordingly. The thermostat has no way of predicting that a threshold temperature will be reached before it already has been reached.

By contrast, a driver knows what is coming ahead of time. An astute driver can predict the future in a way that a thermostat can't. A driver can see that bumper to bumper traffic is ahead. A driver knows that a trailer is about to be backed up a hill. A driver can read a weather report, and a road sign warning of the percent grade ahead. A thermostat can do none of these things. By having a switch that can turn on electric fans in advance of the temperature rising, the time it takes for the temperature to rise can be prolonged, and excessive temperature rise can be forestalled and prevented altogether.

That all being said, one still has to avoid preventing passive air flow through the radiator stack. The installation should consider what ifs... like what if both electric motors failed? What if the fuses blew, and there was no safe place to pull over on the curvy mountain pass? The installation should be implemented as if there was no supplemental electric fan at all.

That is one reason why my twin fans are only 8" in diameter, which is the same height as the transmission cooler itself. Both fans are positioned below the direct air path to the engine driven fan, and the blades are designed with a steeper pitch that permits more air to pass in the space between blades when the electric motors are not driving the fans.

Haven't had an issue in 15 years with the set up. I very rarely ever use the electric fans. Maybe once every couple of years. But when I do need them, they really make a difference, because I turn them on in advance of the need, to avoid having to later dissipate cumulative heat. By turning on the fans early, heat is rejected more rapidly, before it accumulates.

 

I know I've read this before, but I can't remember where....that there isn't a pusher fan capable of providing the airflow needed to replace the stock clutch fan.

 

A lot of really valid points here, thank you for taking the time to post this. Would you happen to have any pictures of your setup?

And correct me if im wrong, but you are saying that you kept the stock clutch fan and installed the two electric fans as pullers also?

 

Ive also read the same thing, as Ive been researching this a lot lately. Im not trying to remove the stock fan anymore. I thought about doing it in the past but I am going to leave it. Im talking about putting a pusher fan in conjunction with the stock puller fan. That way my a/c will have airflow in stop and go traffic.

Im also not looking to put a huge fan in the front and block everything up so that it relies on the electric fan for cooling.


I am going to replace my stock clutch fan in the near future and see what that brings me.

 

Anyway you look at it, putting a fan in front of the clutch fan IS going to block some airflow. It may be a negligible difference except in loaded situations, but if your cooling system is operating properly you don't need the pusher fan. IMHO, it's a mental bandage. If you're intent on adding extra cooling, do the fan switch mod instead.

 

What is the fan switch mod?

I'm not looking for better engine cooling, I'm looking for better ME cooling lol. Truck cools just fine although the most load I've pulled with it was around 7k lbs. The only issue I have is my a/c doesn't work as well as I want it to while in traffic.

 

It took a while, but I finally was able to upload a few pics for you. This forum software sometimes tweaks the pictures sideways, and doesn't offer a tool to orient them correctly again, but I found a workaround. Hope it holds:

Here are my twin fans.

Notice how far apart they are spaced from each other. The gap in between the fans is for multiple reasons:

1. The center gap permits air to pass through the center of transmission cooler without the interference of the electric fans. The center of the transmission cooler coincides with radial path of the engine driven fan, at 6 o'clock. Since the engine driven fan is a big circle, then as we move toward 4 o'clock and 8 o'clock respectively, where the electrical fans are located, there is less interference inline with the direct path of the engine fan. Hope that makes sense. It was kind of hard to find the right words.

2. The center gap also aligns with where the power steering cooler is positioned, in front of the transmission cooler. The idea is to keep the resistance to air flow even all the way across, and since the power steering cooler already presents some resistance to air flow, we don't want to stack resistances with the electrical fan hardware. Hence, the electrical fans were pushed toward either end of the transmission cooler, leaving the center clear.

While the photo above presents the fans upside down on the bench, the photo below shows the fans oriented right side up, hanging off the bench. Added to the rectangular tube that the fans are attached to is the shroud:





The fan shroud is a hybrid formation of a heavy truck mudflap that is laminated with aluminum flashing material, riveted together in a sandwich. This hybridized material combination provided just the right amount of ductility and self supporting rigidity, along with high temperature durability and water impermeability... all while using inexpensive and readily accessible materials.

Since air will follow the least path of resistance, the shroud is a very important element needed to direct air through the cooler and fans, not above and around them.

As installed, in the photo below, you can see the fans, the gap, the shroud, and the installation bar that the fans attach to:





Zip ties on a radiator or heat exchanger are a BAD IDEA. The fact that aftermarket fan companies provide zipties for customers to install their fans directly to the radiators has to be due to them wanting to maintain their consumer sales by making their kits "quick and easy" to install. Longevity is not a concern for them, only sales... and people only write reviews during the first few weeks of owning a product, so ease and speed of installation are important factors for a good review (and thus more sales).

I take a different approach:


Nothing is quick or easy. Everything is custom made. Usually of metal.... that is usually either galvanized or non ferrous, for corrosion resistance. This fan installation is no exception, as these fans are supported by mechanical means entirely independent of the heat exchanger they are close coupled to, with bars and brackets bridged across the front frame core support.

A front view of the fans installed (bumper, power steering cooler, and radiator removed):





In the photo above, notice the gap not only between the fans, but directly BELOW the fans. I didn't want the gap below the fans, because I wanted the path of resistance even between the power steering cooler and either side of the power steering cooler. In fact, if anything, I'd rather have more air pass through and behind the power steering cooler (not shown) than pass underneath the transmission cooler and fans.

In the photo below, the concern above is fixed, by adding a short metal mesh screen below each fan, in order to create more resistance to air flow under the fan (but not stop air flow entirely) so as to encourage air to pass through the fan and transmission cooler passively, even when the electric fans are not activated.





The benefits of these fans are measurable, not just a "mental bandage" as suggested by a previous poster. I instrumented the transmission with an independent gauge, as well as with a factory scan tool, and ran before and after tests at the same weight pulling the same grades in the same ambient temperature conditions. At the time when I made these mods, there was no "6.0" cooler, because this was done years before the 6.0L was introduced. These fans have helped prevent a common transmission heating issue. Because I installed a trans temp gauge as soon as I bought the truck, I knew right away that this issue needed to be solved, and was able to observe the before and after effects of this modification.


This entire post is in answer to this thread's title question, asking if "anyone has added a pusher fan to their cooling system". The answer is yes. However, for optimizing your truck's air conditioning system cooling effectiveness, this is not the right solution. In your case, I recommend buying a 4 way vacuum actuated valve for a Ford Ranger, and installing it in your heater hoses. This will keep hot coolant from circulating in your heater core while the A/C is on. I think you will see a 15 degree drop in AC temperature from just that one (much easier to do) modification.


Yes, absolutely. There is no electric fan system that can match the CFM of the stock mechanical engine fan when the fan clutch is fully engaged. The amount of horsepower that it takes to move an equivalent amount of air would require electric motors that would be too big to fit between the engine and the radiator. Furthermore, the amount of electrical current required to drive those big motors would necessitate much larger alternators, which would cannibalize the engine's horsepower to drive them.

A clutch controlled mechanical engine fan is more efficient and cost effective, all things considered, for the type of towing and hauling duty cycle that the Super Duty is rated for. Lighter duty vehicles, and cars, have lower heat rejection thresholds to meet, and can get by all day with electric fans.

As with all things, there is a cost benefit balance. The electrical hardware required (hvy gauge wiring, battery capacity, alternator output, engine horsepower to drive the alternators) to reject the expected amount of heat generated from the rated amount of work load expected from a 3/4 to 1 ton truck likely exceeds the cost of simply having the engine drive the fan directly by way of a clutch. For applications where less heat needs to be rejected, because less workload is expected, the balance tips in favor of an electrical set up.

I think the stock 7.3L fan can consume up to 27 horsepower at full tilt. Flex-A-Lite makes an aftermarket all electric twin fan and full shroud set to replace this 27HP engine driven fan, but even Flex-A-Lite warns, with all caps emphasis, that their kit is NOT to be used with trucks that tow or haul. Super Duties were made for towing and hauling, but a lot of enthusiasts started racing them, so there is a market and use for the $700 Flex-A-Lite kit. Just don't try and use it if your truck does real work.

 

Wow, that is awesome info! Thank you so much for all of that. Im going to sit down this evening and thoroughly go through that post.


Also I wanted to clear something up as my first post was misleading, since ive gone back and read it.

My problem is with the A/C keeping the inside cool in stop and go traffic. My coolant system work flawlessly and I havent ever seen the needle move, even when towing. So sorry about the confusion here. Im going to edit the first post.

 

This is a very informative, well written post with pictures too! It isn't a "mental bandage" in it's application and usage, but I still don't believe it would be beneficial for most posters on this forum who tow on a consistent basis. Nor would most posters here perform such a well thought out and well executed system.
I still believe it would have a negative effect when towing near the truck's legal capacity limits as well as extreme temperatures which are normal in some spots of the country. The clutch fan does an incredible job and if that's not enough, the snowplow prep clutch fan is the way to go.
Still kind of a moot point since the OP is looking for a different kind of cooling!

 

Hold on now, I messed up at the beginning but I also listed everything I did to my a/c. Either way, the post was still very Informative and completely related to what I'm wanting to do. I want to move more air across the components in front via an electric fan. Ultimately I'm looking for the same end result as his and I can use all of the information he posted to accomplish my task.