Fixed Flex Fan - Complete DIY Part Number List

europachris · **Posted:** Fri Apr 09, 2010 7:24 am

fastRob wrote:

What about the cold weather?
I guess the thermostat better work well.
On cold mornings after chugging up hill on the way to work mine would come to temperature. On the way down the steep hill the temp indicator would drop way down.
I guess the Alaska tent better be on.
Still an interesting mod, let us see how it works out.

My 'stat was doing the same thing, and additionally it was not giving cabin heat anywhere near as fast as it used to, so I knew the thing was bad. I installed an OEM unit and it's back to it's usual quick heating performance. It's 28F here this a.m., so it's going to get a good test.

flash7210 · **Posted:** Fri Apr 09, 2010 4:55 pm

geordi wrote:

I don't know for the speed of the electric fan, do we have a multi-speed fan controller, or is it a simple "you put on the A/C and that fan is cut in with 12v" kinda system?

I guess we will find out soon. I'm thinking about pulling the clutch and engine fan this week, just to lighten the engine a bit and see what it does for temps. It has been warm in Va here for the last few days, I'm interested to see what the engine temp does (if anything different) without that in there.

I'm certainly not adverse to a flex fan for the sheer weight savings. Those iron factory fans weigh a TON on the nose of the engine.

I dont think my fan clutch has ever engaged. I've only heard the electric fan come on but
never the engine. At what temp is the clutch supposed to engage? I have never seen my
temp gauge go beyond halfway. Even in the Florida summer with my grill partially blocked.

kapalczynski · **Posted:** Fri Apr 09, 2010 5:51 pm

fastRob wrote:

What about the cold weather?
I guess the thermostat better work well.
On cold mornings after chugging up hill on the way to work mine would come to temperature. On the way down the steep hill the temp indicator would drop way down.
I guess the Alaska tent better be on.
Still an interesting mod, let us see how it works out.

The thermostat is probably the most important part of the cooling system. If it's not working properly you will be overheated or running too cold and inefficient.

Your coolant temp shouldn't EVER be below 176*(give or take a few degrees) with the factory thermostat even in Alaska once you hit operating temp. The thermostat will not open and let coolant through the radiator part of the system UNTIL the engine gets up to operating temp and opens the stat. Therefore in 20* weather I still run 191* (with a 192* thermostat). I live in Colorado Springs, and the entire time, up and down hills on my way to work I maintain 191-193*F even this last week where temps were 20*, 24*, and 26* on a few of my last days to work the last 2 weeks.

kapalczynski · **Posted:** Fri Apr 09, 2010 5:55 pm

flash7210 wrote:

geordi wrote:

I don't know for the speed of the electric fan, do we have a multi-speed fan controller, or is it a simple "you put on the A/C and that fan is cut in with 12v" kinda system?

I guess we will find out soon. I'm thinking about pulling the clutch and engine fan this week, just to lighten the engine a bit and see what it does for temps. It has been warm in Va here for the last few days, I'm interested to see what the engine temp does (if anything different) without that in there.

I'm certainly not adverse to a flex fan for the sheer weight savings. Those iron factory fans weigh a TON on the nose of the engine.

I don't think my fan clutch has ever engaged. I've only heard the electric fan come on but
never the engine. At what temp is the clutch supposed to engage? I have never seen my
temp gauge go beyond halfway. Even in the Florida summer with my grill partially blocked.

Earlier in this thread, I posted the standards for the Fan clutch. They are 195*-205* F for lock-up and 145-185* F for unlock after locked. I also listed quick and easy test procedures earlier in this thread. You should try them out and see if your fan clutch is working properly.

coldkj · **Posted:** Fri Apr 09, 2010 6:27 pm

Hey kapalczynski, any conclusions about mileage with your new fan? Since it rarely warms up here, and the driveable grades aren't that long, I'm thinking about doing away with my fan, if it will help fuel consumption. Also, what can you tell me about your Hig Beam switch?

kapalczynski · **Posted:** Fri Apr 09, 2010 7:07 pm

coldkj wrote:

Hey kapalczynski, any conclusions about mileage with your new fan? Since it rarely warms up here, and the driveable grades aren't that long, I'm thinking about doing away with my fan, if it will help fuel consumption. Also, what can you tell me about your Hig Beam switch?

So far the mileage seems to be almost exactly the same according to EVIC. I am going on a road trip and leaving the KJ w/ my wife so I will have to start with a fresh tank again most likely to get an accurate test of mileage. I only have ~170 miles on this tank so I want a better average for comparisons. Looking good though.

I have completely gotten used to the hum of the fan now and don't hardly notice it unless I get on it and down shift then it just sounds GOOD.

The high beam switch just overrides the high beams manually so I can have the Highs, lows, and fogs all on at the same time. Works great. Hooked up with a relay. Thats about it.

coldkj · **Posted:** Sat Apr 10, 2010 2:08 am

Thx. I'll be curious about the fuel consumption.

Squeeto · **Posted:** Sat Apr 10, 2010 2:27 am

Squeeto wrote:

Also, I was curious about the electric fan for the air conditioning condenser.
Does it ever get powered to high speed for the sake of engine temperature rather than compressor pressure?

Do a/c-less trucks have this fan?

With all the talk about fans, I checked my electric fan and it isn't working! It should come on with the A/C.
Now the A/C (this time of year at 10*C or 50*F) is working fine.

So my viscous fan never kicks in, the A/C fan is dead in the low speed and the truck read under 180*F all summer.

If you put on a direct drive fan, I am wondering if you need the electric fan at all?

Now I know that the air conditioning condenser is at the front (behind the electric fan), but doesn't drawing air from the backside do the same as pushing from the front?

kapalczynski · **Posted:** Sun Apr 11, 2010 11:55 am

Squeeto wrote:

Also, I was curious about the electric fan for the air conditioning condenser.
Does it ever get powered to high speed for the sake of engine temperature rather than compressor pressure?

Do a/c-less trucks have this fan?

With all the talk about fans, I checked my electric fan and it isn't working! It should come on with the A/C.
Now the A/C (this time of year at 10*C or 50*F) is working fine.

So my viscous fan never kicks in, the A/C fan is dead in the low speed and the truck read under 180*F all summer.

If you put on a direct drive fan, I am wondering if you need the electric fan at all?

Now I know that the air conditioning condenser is at the front (behind the electric fan), but doesn't drawing air from the backside do the same as pushing from the front?

The electric fan does virtually nothing for the engine. It's a pusher and they never do as good as a puller fan. It is a 2 speed fan. Speed 1 at xxx* temp and speed 2 at xxx* (higher) temp. Probably no reason to run it at all with my flex fan setup. I may disable it for the AC as I do not think it is necessary to run with it and make the alternator work harder/kill economy a bit more with AC. Just a thought.

Squeeto · **Posted:** Sun Apr 11, 2010 12:22 pm

Ok, very reliable flex fan, no viscous clutch, no electric fan.

Now remove the viscous heater and replace with a belt roller :twisted:

racertracer · **Posted:** Sun Apr 11, 2010 7:21 pm

How did you get the fan clutch off?

What did you use to hold the shaft from turning?

kapalczynski · **Posted:** Sun Apr 11, 2010 8:18 pm

racertracer wrote:

How did you get the fan clutch off?

What did you use to hold the shaft from turning?

It wouldn't budge for me w/just a wrench. It comes easy if you use a cresent wrench and tap it left with a small hammer. The impact knocks it loose easy. You shouldn't need to hold anything. I've done it this way 3 times and so far easy every time.
- Mark

racertracer · **Posted:** Sun Apr 11, 2010 9:07 pm

It has very little resistance though, it seems that the sepentine belt may be loose I have no idea how tightt the belt should feel, it wont hold the shaft from turning .. how do I tighten the belt?

Squeeto · **Posted:** Sun Apr 11, 2010 10:58 pm

There is a spring loaded tensioner that is supposed to keep the belt at proper tension.
If you need to temporarily tighten the accessory belt, I guess you could pull on it.

You need a serpentine tool with a 15mm socket (or breaker bar with extension). Put it on the smallest pulley toward the bottom left (facing the engine) and pull away from the battery.

geordi · **Posted:** Mon Apr 12, 2010 11:43 am

But don't pull too hard, that will unscrew that reverse-threaded bolt holding the tensioner.

fastRob · **Posted:** Mon Apr 12, 2010 12:59 pm

kapalczynski wrote:

Squeeto wrote:

Also, I was curious about the electric fan for the air conditioning condenser.
Does it ever get powered to high speed for the sake of engine temperature rather than compressor pressure?

Do a/c-less trucks have this fan?

With all the talk about fans, I checked my electric fan and it isn't working! It should come on with the A/C.
Now the A/C (this time of year at 10*C or 50*F) is working fine.

So my viscous fan never kicks in, the A/C fan is dead in the low speed and the truck read under 180*F all summer.

If you put on a direct drive fan, I am wondering if you need the electric fan at all?

Now I know that the air conditioning condenser is at the front (behind the electric fan), but doesn't drawing air from the backside do the same as pushing from the front?

The electric fan does virtually nothing for the engine. It's a pusher and they never do as good as a puller fan. It is a 2 speed fan. Speed 1 at xxx* temp and speed 2 at xxx* (higher) temp. Probably no reason to run it at all with my flex fan setup. I may disable it for the AC as I do not think it is necessary to run with it and make the alternator work harder/kill economy a bit more with AC. Just a thought.

I pulled the fan when I replaced the t/c and transmission pump. The EGR causes heat buildups and heavy pedal applications followed by quick shutdowns can damage turbo or leave the 4 cyl kettle to boil. This is an aluminum engine and heads do warp.
I just needed the space for my new transmission cooler and have had no overheating issues.

kapalczynski · **Posted:** Tue Apr 13, 2010 9:47 pm

racertracer wrote:

It has very little resistance though, it seems that the sepentine belt may be loose I have no idea how tightt the belt should feel, it wont hold the shaft from turning .. how do I tighten the belt?

Did you try the adjustable wrench with the hammer? GDE recommends this same way. I had good luck this way as well myself. You can use the tensioner to tighten the serpentine belt, but the crank will still turn with the belt tightened and a wrench on the fan clutch bolt if you do not impact the wrench to break the fan loose.

- Mark

kapalczynski · **Posted:** Tue Apr 13, 2010 10:09 pm

fastRob wrote:

I pulled the fan when I replaced the t/c and transmission pump. The EGR causes heat buildups and heavy pedal applications followed by quick shutdowns can damage turbo or leave the 4 cyl kettle to boil. This is an aluminum engine and heads do warp.
I just needed the space for my new transmission cooler and have had no overheating issues.

A little confused by your statement...why if you stressed turbo damage and head warpage would you remove a fan??? Is the transmission cooler for the oil running to the turbo or something? That does seem like a good idea to cool the oil prior to it being used to cool the turbo...is that what you did? Is that why it was more important to have a transmission cooler than a radiator fan? That does make some sense if so.

You still run the risk of overheating w/o the fan...even more so. Especially on low speed traffic or up hills when TC is locked ane engine is low rpms with alot of fuel proportional to the rpm. This is MORE important because you have aluminum heads and an iron block that both have different expansion rates. If you watch your temp like a hawk, then you're good, but not worth the hastle in my opinion if i start overheating and have to pull off the road.

How thick is your transmission cooler??? Just curious, because I can measure the distance from my flexfan to the radiator and see if there is room for your cooler with my setup...best of both worlds if you can still have a fan. There is a bit more room with out the fan clutch and the flex fan sits pretty close to the block so there might be room. It would be cool to run the cooler and the flex fan and have even better pre turbo oil cooling provided by both the cooler AND the flex fan directly linked to the crank and pulling ALOT of air through the oil cooler. - Great idea

- Mark

fastRob · **Posted:** Wed Apr 14, 2010 1:11 pm

kapalczynski wrote:

A little confused by your statement...why if you stressed turbo damage and head warpage would you remove a fan??? Is the transmission cooler for the oil running to the turbo or something? That does seem like a good idea to cool the oil prior to it being used to cool the turbo...is that what you did? Is that why it was more important to have a transmission cooler than a radiator fan? That does make some sense if so.

You still run the risk of overheating w/o the fan...even more so. Especially on low speed traffic or up hills when TC is locked ane engine is low rpms with alot of fuel proportional to the rpm. This is MORE important because you have aluminum heads and an iron block that both have different expansion rates. If you watch your temp like a hawk, then you're good, but not worth the hastle in my opinion if i start overheating and have to pull off the road.

How thick is your transmission cooler??? Just curious, because I can measure the distance from my flexfan to the radiator and see if there is room for your cooler with my setup...best of both worlds if you can still have a fan. There is a bit more room with out the fan clutch and the flex fan sits pretty close to the block so there might be room. It would be cool to run the cooler and the flex fan and have even better pre turbo oil cooling provided by both the cooler AND the flex fan directly linked to the crank and pulling ALOT of air through the oil cooler. - Great idea

- Mark

Mark,
The separate 40,000 lb transmission cooler with thermal bypass increases existing radiator cooling capacity by reducing demand. The EGR inactivation also reduces radiator demand. As long as there is a cool down idling after a long heavy haul the electric radiator is not required IMO. The huge stock fan or a good flex fan should be enough. The e fan is out of my way, the e- fan shroud is not blocking air flow to the radiator or transmission cooler. I like simpler things.
There was no modification to the turbo oil cooling.

kapalczynski · **Posted:** Wed Apr 14, 2010 8:28 pm

fastRob wrote:

kapalczynski wrote:

A little confused by your statement...why if you stressed turbo damage and head warpage would you remove a fan??? Is the transmission cooler for the oil running to the turbo or something? That does seem like a good idea to cool the oil prior to it being used to cool the turbo...is that what you did? Is that why it was more important to have a transmission cooler than a radiator fan? That does make some sense if so.

You still run the risk of overheating w/o the fan...even more so. Especially on low speed traffic or up hills when TC is locked ane engine is low rpms with alot of fuel proportional to the rpm. This is MORE important because you have aluminum heads and an iron block that both have different expansion rates. If you watch your temp like a hawk, then you're good, but not worth the hastle in my opinion if i start overheating and have to pull off the road.

How thick is your transmission cooler??? Just curious, because I can measure the distance from my flexfan to the radiator and see if there is room for your cooler with my setup...best of both worlds if you can still have a fan. There is a bit more room with out the fan clutch and the flex fan sits pretty close to the block so there might be room. It would be cool to run the cooler and the flex fan and have even better pre turbo oil cooling provided by both the cooler AND the flex fan directly linked to the crank and pulling ALOT of air through the oil cooler. - Great idea

- Mark

Mark,
The separate 40,000 lb transmission cooler with thermal bypass increases existing radiator cooling capacity by reducing demand. The EGR inactivation also reduces radiator demand. As long as there is a cool down idling after a long heavy haul the electric radiator is not required IMO. The huge stock fan or a good flex fan should be enough. The e fan is out of my way, the e- fan shroud is not blocking air flow to the radiator or transmission cooler. I like simpler things.
There was no modification to the turbo oil cooling.

Ok, I think I got what your saying. Thought you removed the main fan, you originally didn't specify. So you removed the electric fan it sounds like to make room for the transmission cooler. So you are cooling the transmission with the new cooler (40k lb tow rating for the cooler i suppose). Did you completely bypass the transmission cooler core in the radiator, or you using both? So it was your transmission overheating that you attribute the damage to your pump and TC?

By eliminating the main fan slip of the fan clutch I have vastly improved the antifreeze (engine), transmission fluid (transmission) and air (intercooler) cooling. I'm not sure if it is even necessary to add a second transmission cooler, I will monitor the transmission temps with the software I have and compare with the other factory fan and clutch setup.

Good stuff man.

- Mark

Fixed Flex Fan - Complete DIY Part Number List

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