Clutch Fan delete

Rixram · **Posted:** Mon May 04, 2015 2:57 pm

CRDers:

I did my timing belt back in July 2012. When I reassembled, I opted to not return the mechanical fan to the vehicle, leaving any idle speed cooling to the electric fan. In the following 3 years, I have not overheated, even when towing (towed a 5K lb boat back and forth from the launch ramp, est. 5 miles).

I have the in-line thermostat, with a 195° setting. Is there any reason why you think the mechanical fan needs to go back on the engine? Note: I sold that boat, and no longer tow heavy loads.

My logic is that once I am over 20-25 mph, airspeed is moving sufficient air over the radiator to provide cooling. While at idle, the engine burns very little fuel (as we know, these things do not like to heat up in winter past the viscous heater shutoff temp (ECO tune). With A/C on, and long summer idle times or slow moving traffic, I've never exceeded 195° on the temp gauge.

Edit for clarification: there is the stock factory electric fan already on the Jeep CRDs. I kept mine on there as well, and did not remove it.

Thoughts?

weeks101 · **Joined:** Mon Jul 30, 2012 3:29 pm **Posts:** 747

Your intake air temps will be lower with the mechanical fan in place. It keeps air flowing over the intercooler at all times, without it your intercooler will heat soak, particularly when stopped or in stop-and-go traffic.

Heat soak is when the intercooler can't dissipate the heat that it absorbs from the turbo fast enough. When an intercooler can't cool the charge air by removing the heat from it, it loses its effectiveness.

Being in Minnesota in the middle of the continent, we have very extreme hot and cold temps and so we run the mechanical fan in the summer but remove it in the winter.

thermorex · **Posted:** Mon May 04, 2015 3:32 pm

Agree with weeks, you can at least put an efan there and start it manually when it's hot and driving stop and go.

Rixram · **Posted:** Mon May 04, 2015 3:39 pm

weeks101 wrote:

Your intake air temps will be lower with the mechanical fan in place. It keeps air flowing over the intercooler at all times, without it your intercooler will heat soak, particularly when stopped or in stop-and-go traffic.

Heat soak is when the intercooler can't dissipate the heat that it absorbs from the turbo fast enough. When an intercooler can't cool the charge air by removing the heat from it, it loses its effectiveness.

Being in Minnesota in the middle of the continent, we have very extreme hot and cold temps and so we run the mechanical fan in the summer but remove it in the winter.

I understand it is substantially less air, but wouldn't the electric fan accomplish limited intercooler heat exchange? Oh, and the climate here (Rhode Island) is similar in summer, but less ice-age in winter (I lived in MN, WI until age 10).

At idle temps, the turbo is not adding anything, either. I am not sure of the spin-up rpm on the turbo, but the butt-dyno seems to recall something in the 1500 rpm range. Right-ish?

Rixram · **Posted:** Mon May 04, 2015 3:42 pm

thermorex wrote:

Agree with weeks, you can at least put an efan there and start it manually when it's hot and driving stop and go.

Thermorex: I apologize for not clarifying: there already is a factory electric fan in there. In addition to the stock e-fan, is there a definite need for the mechanical fan, if not doing long-distance towing in slow traffic?

Thanks!

weeks101 · **Joined:** Mon Jul 30, 2012 3:29 pm **Posts:** 747

Rixram wrote:

I understand it is substantially less air, but wouldn't the electric fan accomplish limited intercooler heat exchange? Oh, and the climate here is similar in summer, but less ice-age in winter (I live in MN, WI until age 10).

At idle temps, the turbo is not adding anything, either. I am not sure of the spin-up rpm on the turbo, but the butt-dyno seems to recall something in the 1500 rpm range. Right-ish?

If memory serves, the stock electric fan only turns on when coolant temp hits 203F. The mechanical fan is spinning all the time.

The intercooler absolutely will heat soak even at idle with 0 boost generated by the turbocharger. Exhaust gasses are flowing through the turbocharger, heating it up; your turbo is sucking air where its heated by the turbocharger, travels through the intercooler where heat is allowed to dissipate. If there is no airflow across the intercooler, temps will climb and it will heat soak until you start moving, airflow increases and your intake temps stabilize.

I have been monitoring intake temps for 6-7 months with a thermocouple unit, both with and without mechanical fan. Generally: on a mild day like today (70F) intake temps with no mechanical fan would exceed 50-75F above ambient at idle. With a mechanical fan intake temps are pretty stable, hovering around 10-20F above ambient.

Rixram · **Posted:** Mon May 04, 2015 4:08 pm

weeks101 wrote:

Rixram wrote:

I understand it is substantially less air, but wouldn't the electric fan accomplish limited intercooler heat exchange? Oh, and the climate here is similar in summer, but less ice-age in winter (I live in MN, WI until age 10).

At idle temps, the turbo is not adding anything, either. I am not sure of the spin-up rpm on the turbo, but the butt-dyno seems to recall something in the 1500 rpm range. Right-ish?

If memory serves, the stock electric fan only turns on when coolant temp hits 203F. The mechanical fan is spinning all the time.

The intercooler absolutely will heat soak even at idle with 0 boost generated by the turbocharger. Exhaust gasses are flowing through the turbocharger, heating it up; your turbo is sucking air where its heated by the turbocharger, travels through the intercooler where heat is allowed to dissipate. If there is no airflow across the intercooler, temps will climb and it will heat soak until you start moving, airflow increases and your intake temps stabilize.

I have been monitoring intake temps for 6-7 months with a thermocouple unit, both with and without mechanical fan. Generally: on a mild day like today (70F) intake temps with no mechanical fan would exceed 50-75F above ambient at idle. With a mechanical fan intake temps are pretty stable, hovering around 10-20F above ambient.

Great information: thank you!

thermorex · **Posted:** Mon May 04, 2015 6:06 pm

Rixram wrote:

thermorex wrote:

Agree with weeks, you can at least put an efan there and start it manually when it's hot and driving stop and go.

Thermorex: I apologize for not clarifying: there already is a factory electric fan in there. In addition to the stock e-fan, is there a definite need for the mechanical fan, if not doing long-distance towing in slow traffic?

Thanks!

No need to apologize, I know about the stock efan pusher but as weeks said, it starts kind of late in the game, when you're already towards overheating.

Funny, I was just thinking on adding a probe for intake temps. It's not that you'll break the car without a fan for intercooler, but won't be as efficient. Same as for your ac.

flash7210 · **Posted:** Mon May 04, 2015 6:10 pm

I too removed my clutch fan when I did my t-belt about 3 years ago.
No over heating problems.
While driving, Intake air temps can be 20-30 degrees above ambient. But while stopped it can get higher.
The main drawback here is that the fan will only turn on under one of these two conditions:
1. A/C is on. And with the A/C on that adds more heat.
2. Engine temp hits 205 F.
If you are slowly climbing a steep hill in the middle of summer, it might seem like a good idea to turn the A/C off to reduce the heat through the radiator. But then again, A/C off = no fan until 205 degrees. And you WILL 205 really quick when climbing a hill in summertime. At that point the electric fan may not be enough to bring engine temps back down.

I am going to work on a simple modification that will allow manual control of the fan. The way it will work is that the fan will turn on low with the ignition key on and will stay on low while the engine is running. A toggle switch on the dash will allow you to switch between low and high fan speeds.
I've done some testing and it works. I just gotta figure out a way to run the wiring and mount the switch on the dash.

But first I have to get my engine back together.

Note: my intake air temps were taken from the MAP sensor using Torque Pro.

thermorex · **Posted:** Tue May 05, 2015 7:46 am

flash7210 wrote:

I too removed my clutch fan when I did my t-belt about 3 years ago.
No over heating problems.
While driving, Intake air temps can be 20-30 degrees above ambient. But while stopped it can get higher.
The main drawback here is that the fan will only turn on under one of these two conditions:
1. A/C is on. And with the A/C on that adds more heat.
2. Engine temp hits 205 F.
If you are slowly climbing a steep hill in the middle of summer, it might seem like a good idea to turn the A/C off to reduce the heat through the radiator. But then again, A/C off = no fan until 205 degrees. And you WILL 205 really quick when climbing a hill in summertime. At that point the electric fan may not be enough to bring engine temps back down.

I am going to work on a simple modification that will allow manual control of the fan. The way it will work is that the fan will turn on low with the ignition key on and will stay on low while the engine is running. A toggle switch on the dash will allow you to switch between low and high fan speeds.
I've done some testing and it works. I just gotta figure out a way to run the wiring and mount the switch on the dash.

But first I have to get my engine back together.

Note: my intake air temps were taken from the MAP sensor using Torque Pro.

Other than money reasons, is there anything else that keeps you from installing a new separate puller fan? I'd say it's easier to leave the car wiring as it is and add your own efan to replace the stock viscous. Plus there is less risk if one of them breaks.

dirtmover · **Posted:** Tue May 05, 2015 8:07 am

thermorex wrote:

It's not that you'll break the car without a fan for intercooler, but won't be as efficient.

Heat tends to accelerate aging in plastics which can lead to premature brittleness and/or fractures. Given our cheap, crappy plastic intercooler is already fragile are we just making matters even worse leaving the fan off? I never re-installed my mechanical fan after doing the TB last fall but am still on the fence whether to put it back for Summer.

flash7210 · **Posted:** Tue May 05, 2015 8:13 am

thermorex wrote:

flash7210 wrote:

I too removed my clutch fan when I did my t-belt about 3 years ago.
No over heating problems.
While driving, Intake air temps can be 20-30 degrees above ambient. But while stopped it can get higher.
The main drawback here is that the fan will only turn on under one of these two conditions:
1. A/C is on. And with the A/C on that adds more heat.
2. Engine temp hits 205 F.
If you are slowly climbing a steep hill in the middle of summer, it might seem like a good idea to turn the A/C off to reduce the heat through the radiator. But then again, A/C off = no fan until 205 degrees. And you WILL 205 really quick when climbing a hill in summertime. At that point the electric fan may not be enough to bring engine temps back down.

I am going to work on a simple modification that will allow manual control of the fan. The way it will work is that the fan will turn on low with the ignition key on and will stay on low while the engine is running. A toggle switch on the dash will allow you to switch between low and high fan speeds.
I've done some testing and it works. I just gotta figure out a way to run the wiring and mount the switch on the dash.

But first I have to get my engine back together.

Note: my intake air temps were taken from the MAP sensor using Torque Pro.

Other than money reasons, is there anything else that keeps you from installing a new separate puller fan? I'd say it's easier to leave the car wiring as it is and add your own efan to replace the stock viscous. Plus there is less risk if one of them breaks.

After reading your thread about the FF Dynamics fan install, I started thinking about installing a big electric puller fan. But I would only want to have one fan in there, just seems like it would better to have just one big puller than having a pusher and puller.
So yeah, the FF Dynamics fan is kinda expensive. So I started looking into other fans like the multitude of electric fans available from Summit. And other OEM type fans like the one off a Ford Taurus.
Then I started thinking about modifying the whole radiator sandwich by:
1. removing the stock electric and going with a big electric puller fan.
2. removing the stock AC condenser/transmission cooler and replacing with a V6 type condenser that is without the trans cooler and adding a separate, larger, trans cooler in front of the condenser. (I think this would work but I'm not exactly sure)

So yeah, its all about $$$.
I really dont have the money to be spending on experiments. Especially when what I have (just one stock electric fan) seems to be working just fine.
However, on two occasions while slowly going up a steep hill, the temperature gauge got to the "1-o-clock" position. Not for very long and not overheating but it was enough to get my attention.
And one of those two occasions was in the dead of winter.
So that was when I decided that I needed some way of manually controlling the fan.
And its a easy and cheap mod. Just remove one of the fan relays and add a toggle switch and some wires.

thermorex · **Posted:** Tue May 05, 2015 8:57 am

I agree with the statements and makes sense, I was just curious. In my opinion is a bit risky to depend on just one fan, in case it fails. You can always make your own shroud from an aluminum sheet and have a cheaper backup 14-16 inch fan installed. Even with this choice you'll still spend easy 100+.

I do have a bigger trans cooler mounted in front of the condenser, but I had to ditch the stock pusher and go with 2 7 inch fans due to fitment issues. Probably the cfm of both fans is max half of the stock pusher, but considering the circumstances I didn't have a choice. So with the auxiliary transmission cooler (which deletes the stock trans cooler) I had to have the ffdynamics fan as a reliable cooling alternative. Works for me, but as you said, it adds a lot of modding time plus some $$$ (efan, controller, trans cooler, lines, wires, etc). Depending on how much time and money you are willing to invest, it may or may not worth. I'd like to have the option to keep the viscous and just manually adjust the clutch, to couple more in hot weather and couple less in cold winter temperatures. Like a winter setting where it barely couples on engine operating temps and a summer setting where it couples "more", i.e. spins more in sync with engine rotation. Not sure if anybody makes such a viscous.

WWDiesel · **Posted:** Tue May 05, 2015 10:24 am

Another direction,
Some on this list have advocated the replacing of the OEM metal cooling fan with the gasser HD plastic towing fan, part no. 52079654AE along the the Hayden heavy duty viscous clutch part no. 2905. Benefits claimed are better cooling, less rotational weight, and better fuel milage... :mrgreen:

flash7210 · **Posted:** Tue May 05, 2015 11:07 am

thermorex wrote:

... but I had to ditch the stock pusher and go with 2 7 inch fans due to fitment issues...

Funny, I was thinking about adding two 6-8 inch pullers to the upper left and right corners of the radiator because those areas are not in the direct flow of the stock pusher.

Quote:

I'd like to have the option to keep the viscous and just manually adjust the clutch...

There are electronically controlled fan clutches.
Dont know how well they work or if one will fit the liberty.

Old Humvee's used hydraulically controlled fan clutches using fluid pressure from the power steering pump.

thermorex · **Posted:** Tue May 05, 2015 11:41 am

What I don't like with my current setup is that when I manually override the fan to start, it starts in "full throttle", i.e. Max speed. I'd like to have an option to dial in the speed as needed (which is probably a knob/resistor mounted where the thermocouple is in the fan controller). This kind of defeats the purpose of the electric fan clutch, lol.

What I didn't like at the stock fan was that is was running all the time in the winter keeping the engine cool. Even with blankets on the grille it still sucked air from under the engine and bumper.

I think engine oil would be probably better for a fan clutch, as would indicate better the temperature of the engine (can be flow implemented, higher temps, more flow, but then you're tied to specific oil weights) not sure how risky is to have this implemented and how doable it is.

Oh, btw, per some old measurements I made, you can fit 4 10inch fans on the radiator. I think you can get one 10 inch or less fan for about 20-ish from eBay or Amazon.

mk38tech · **Joined:** Thu Dec 08, 2011 7:25 pm **Posts:** 72

for a few months ive been looking at the flex-a-lite black magic 180. just couldnt figure out how to use it since its 21-1/2 inches wide. i woke up yesterday and said f it. ill turn the darn thing sideways so i pulled the trigger today. install was a breeze. trans temp is staying WAY down. even at a humid 90 degrees out. i have never seen, or been able to get my electric fan on the condenser to run, so a month ago i wired it to a 3 way switch so i can control it. ac on or off, never worked before. now it does. when i want it to. if i have any problems i may swap that tiny thing out too. ive read it only pushes 650 cfm so.... ive already found a few fans that pump out 2500 or so that are just as small. ill be putting a3 way switch on the black magic in the next few days. waiting to see how it does in the 100 degree 98% humidity days here in VA haha. side note. i have had the dual electric fans, flex-a-lite 262, on my cummins for 5 years, and have towed 12k from FL to VA, (in the winter) and had no problems, but i have a VERY expensive suncoast transmission as well with the double deep mag hytec!! second side note, i ordered the flex 45951 aux cooler for the truck, that thing moves some serious air. cheap from advance with a discount code!! get one yall

flash7210 · **Posted:** Sat Jun 20, 2015 5:48 am

Cool.
Can you post some oics of your fan install?

Clutch Fan delete

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