nvr-enuf

Hello everyone - what is the best / easiest way to ensure that the clutch fan is fully engaged / at the most air flow? Do I do this by putting the A/C on or can I do with without having the additional load of the A/C compressor?

Can I add a direct 12V switch to engage the fan? I want to do this when climbing hills while pulling a trailer to keep the trans temp down below 230F.

Thanks
Scott

cdennyb

Honestly, if you want the trans temp lowered, why not put a dedicated big truck hydraulic oil cooler up under the truck near the transmission with an electric fan and it's own thermostat on it? This way, not only do you cool the trans seperately and only when needed but you take a BIG load off the coolant engine radiator too. The truck will run cooler and the trans will be happy as well. Your trans oil shouldn't run any hotter than your coolant temp, since it's running thru the radiator core anyway, unless yours has a seperate front mounted cooler.

That's what I'd do.

jhenson

To insure that the fan is operating properly when clutch is engaged, place fingers into said fan and see how many you have left once test is completed .

Seriously though......DON'T DO THAT!!!! You can turn your a/c on and cover the condenser with a blanket to obstruct airflow and cause the fan clutch to engage. They're electric clutches so either they work or they don't. I know this from past experiences. I turned my a/c on going down the highway one day and all was well....came to a stop and cold air got noticeably warm. Popped the hood and fan was barely turning....slow enough that I could grab it and stop it and it was almost 100* outside!! Called dealership and told them what I had done and they acted like I had lost my mind..."YOU NEVER GRAB THAT FAN.....IT'LL CUT YOUR FINGERS OFF!!!!" they said. I've been around the block a time or two so I knew what I was doing. When I say the fan was barely spinning......you could count the blades as it was turning.

CoastalDav

First get under the front of the truck and follow the wire down from the clutch to the connection point. Make sure the connector is tight. If you find it full of light oil and the wires are coated, you may be loosing fluid from the coupler on the fan.

Mine was loose when I first got the truck. I put a small tie wrap around the connector and have been free of problems since then.

With the truck at operating temp, open the hood and listen for the fan to pick up in noise level and force. It puts out alot of air when fully hooked up. Mine will pick up and lay down a couple times in 4 minutes. Best way to help the tranny cool down is to put it in nuetral and wait a few minutes. Stock torque converters run hot anyway. My TFI tripple locker runs 15 degrees cooler than the stock one when its 90 outside.

Dave

goran_volvo

There is no power to this, read how the clutch fan works
@ CoastalDav
It is good for you to read this

There are no wires

A fan clutch is a thermostatic device that exists as an integral component of certain automotive cooling systems. When the engine is cool or even at normal operating temperature, the fan clutch partially disengages the engine's mechanically-driven radiator cooling fan, generally located at the front of the water pump and driven by a belt and pulleyconnected to the engine's crankshaft. This saves power, since the engine does not have to fully drive the fan.
However, if engine temperature rises above the clutch's engagement temperature setting, the fan becomes fully engaged, thus drawing a higher volume of ambient air through the vehicle's radiator, which in turn serves to maintain or lower the engine coolant temperature to an acceptable level.
Mechanical fans are most common in trucks and SUVs, and some RWD cars. This is easier to accomplish because the engine is mounted longitudinally, with the belt accessory components mounted facing the radiator. The fan will spin in between the radiator and the engine to help with cooling.
Most fan clutches are viscous or "fluid" couplings, combined with a bi-metallic sensory system similar to that in athermostat. Some clutches are electronically controlled (in place of the bi-metallic strip). These provide the potential to control the level of engagement depending on any number of inputs. Common controlling factors might include engine oil temperature, transmission oil temperature, coolant temperature, AC system pressures and ambient air temperature.
A fan clutch is as reliable as any other component on a vehicle, yet sometimes they fail. A common symptom of fan clutch failure is overheating at idle or in heavy traffic. Bad fan clutches can also cause poor performance of the car's air conditioning system because the fan also cools the air conditioner's condenser, which is directly in front of the radiator. A fan clutch can also fail in a stuck on position where engine power is lost even when the fan is not necessary. This type of failure can also decrease fuel economy.
Another potential symptom of fan clutch failure (always drawing air at a high rate) in a cold weather climate is that the heating system blows lukewarm air never delivering sufficient hot air.

CoastalDav

Goran;

Sorry your not up on what going on with these trucks. It is possible that the 04.5 truck in question still may have a non wired fan clutch. I don't know for sure when the fan clutch became controlled by the computer. I assumed 04.5 to 2007 5.9 was the same engine and control system. So if I'm incorrect about the 04.5 having a computer controlled fan, I did not give the right info.
That happens once and awhile.

However, I have an 2006 and the fan clutch is controlled by the computer through a connection to wiring harness.

Your right about how a non wired fan clutch works.

Dave

CTD NUT

Yes, there are wires. And yes, there is electrical power running to the clutch.

In bold is the kind of cooling fan clutch used on all 03 and up CTD powered Dodges. Coastal Dave is correct. While it is a vicous clutch assembly, it is electrically locked for positive engagement which is controlled by the ECM. Coolant temps at the engine are sensed through the coolant temp senser and the ECM engages the clutch when required. The airflow from the rad that flows over the clutch will not lock this fan.

ramman

You can put a jumper from a grounded source to #1 pin in the connector ,with a switch if you choose . It should be the brown/orange pin #1 of the fan pigtail,it's not an instant turn on or off like an ac clutch but ,somewhere in the manual it gives testing procedure but I can't find it now.

nvr-enuf

thanks for the response