Power Wagon Registry

Everyday when I first turn my truck on the engine fan is on. It will stay on until I get up to highway speeds or keep wide open throttle for 10-15 seconds. It can be 75 degrees or like yesterday 102 and it doesn't matter the fan is on. Does anyone else have this issue?

This is normal as the viscus fluid inside the clutch has to warm up. Our trucks are worse than most as we have a HD fan clutch that engages (locks in) at a lower temperature for the low speed wheeling application our trucks were designed for.

It is when it doesn't do that, this is when you need to worry.

Mopar6.4 wrote:Everyday when I first turn my truck on the engine fan is on. It will stay on until I get up to highway speeds or keep wide open throttle for 10-15 seconds. It can be 75 degrees or like yesterday 102 and it doesn't matter the fan is on. Does anyone else have this issue?

Mine has been stuck on nearly all day a couple times. Usually it only fails to disengage for a mile or so after I first start it in the morning, but it is a known problem with these trucks and it's annoying as hell. I'm just waiting for the day mine finally stops disengaging all together so I'll have an excuse to rip it out and drop in an electric fan.

Thanks guys

The fan is supposed to engage when the engine starts up there is no problem unless the fan does not engage here's some additional info.

"The Thermal Fan Clutch is engaged at startup because a non-spinning thermal clutch will drain the fluid into the working area of the reservoir. When the clutch begins to spin, the pumping action of the clutch in it's cool state moves the fluid way from the working area until the valve moved it back."

http://www.offroaders.com/tech/fan-clutch.htm
Also:
http://www.haydenauto.com/featured%20pr ... ntent.aspx

Wirebrush wrote:

Mopar6.4 wrote:Everyday when I first turn my truck on the engine fan is on. It will stay on until I get up to highway speeds or keep wide open throttle for 10-15 seconds. It can be 75 degrees or like yesterday 102 and it doesn't matter the fan is on. Does anyone else have this issue?

Mine has been stuck on nearly all day a couple times. Usually it only fails to disengage for a mile or so after I first start it in the morning, but it is a known problem with these trucks and it's annoying as hell. I'm just waiting for the day mine finally stops disengaging all together so I'll have an excuse to rip it out and drop in an electric fan.

Not many electric fans will keep up with a big V8 in a truck. I would avoid any aftermarket, maybe a Taurus or Windstar fan locked on the high speed. We experimented with these a lot in my buddy's K30 w/454. Took two Windstar fans (Taraus fans were too wide) to keep it cool empty. Aftermarket was a joke. Hard to beat a mechanical fan for cooling in a towing application.

ramv wrote:

Wirebrush wrote:

Mopar6.4 wrote:Everyday when I first turn my truck on the engine fan is on. It will stay on until I get up to highway speeds or keep wide open throttle for 10-15 seconds. It can be 75 degrees or like yesterday 102 and it doesn't matter the fan is on. Does anyone else have this issue?

Mine has been stuck on nearly all day a couple times. Usually it only fails to disengage for a mile or so after I first start it in the morning, but it is a known problem with these trucks and it's annoying as hell. I'm just waiting for the day mine finally stops disengaging all together so I'll have an excuse to rip it out and drop in an electric fan.

Not many electric fans will keep up with a big V8 in a truck. I would avoid any aftermarket, maybe a Taurus or Windstar fan locked on the high speed. We experimented with these a lot in my buddy's K30 w/454. Took two Windstar fans (Taraus fans were too wide) to keep it cool empty. Aftermarket was a joke. Hard to beat a mechanical fan for cooling in a towing application.

I've seen someone selling an electric fan setup for the CTD Ram trucks, so I would imagine that something that's even marginal for a 1 ton Cummins would be plenty adequate for a 6.4 hemi 3/4 ton that's not being used to tow anything.

But if it is working the way it is supposed to, why the rush to change it? Nothing is wrong, according to your description.

I've seen someone selling an electric fan setup for the CTD Ram trucks, so I would imagine that something that's even marginal for a 1 ton Cummins would be plenty adequate for a 6.4 hemi 3/4 ton that's not being used to tow anything.[/quote]

I've seen this setup too. But it flat out states not to be used for towing. The stock cummins fan pulls something like 25,000cfm and the elect are way under that. The elect is flex-a-lite or something and iirc it's under 10,000cfm Max. Guys do it for peak power numbers because the stock fan drags down 26-28hp to make that. That's at full lock though. I've only once had mine get close to lock and it was 35°C idling with the ac at full blast. Idk how you fellows live in that 40° plus weather. Anything over 75°f is too hot

FirerescuePW wrote:But if it is working the way it is supposed to, why the rush to change it? Nothing is wrong, according to your description.

It has on a few occasions refused to disengage, even when driving very easy in 50 to 60 degree temps for hundreds of miles. It is quite irritating to hear the noise of the fan over the sound of the Mufflex exhaust and know that it's burning extra gas and just make a bunch of obnoxious noise. I have read on other boards of other people having the same issue, but the fan clutch won't ever disengage. I have previously owned and 04 Dakota that the fan was constantly engaged on. It was miserable. It got 14mpg while my 04 Grand Cherokee with the same engine got 21mpg.

Your 04 grand Cherokee had a hydraulic powered fan run off the power steering pump. Wife has an 02. I've had to fix those stupid hi pressure lines that go down to it. Fantastic system when it works. Far superior to electric. When it's working.