I've noticed this behavior recently. I don't know if I wasn't noticing it before, or it wasn't happening.

It's happened a couple of times. I'll be towing the RV (total weight 16k#) up a slight grade in 3rd gear. There was a 20-30 mph headwind that day so I couldn't even use OD unless I going down a pretty steep grade. The air temp was about 75. EGT's were between 1000 and 1100. The transmission temp was about 170 (I have a 6.0 trans cooler - best money I ever spent). I'm doing 55 or 60. I don't have a coolant gauge but the factory gauge wasn't higher than normal, for whatever that's worth.

And then I'll hear the fan kick on. It roars like a lion. I can hear it over the radio with the windows open or closed and the AC on high. It will stay engaged until I hit level or a downhill grade and after a few moments the fan disengages. The extra engine load increases the EGTs further, forcing me to back off the throttle even more.

It's very annoying. Is this normal and is there a solution to this? An electric fan conversion maybe? Do I just need a newer or better fan clutch?

 

This is normal The fan kicks on when hot air hits the clutch. I can't remember the temp off the top of my head somewhere around 210?.

The factory coolant gauge is more of an idiot light and only moves just before it's too late.

From what I understand an electric fan wouldn't do much as the clutch is independent from the coolant.

 

The other question that I forgot to ask is, at 60mph, does having the fan engage *really* make that much of a difference?

I wouldn't care except it tends to spike the EGT by 50 or 75 degrees when it does it.

 

All sounds normal, it's so noisy and robs so much power because it's pulling more air than you can possibly imagine across the radiator. If it didn't, you would over heat. I don't know if there's an electric fan out there that could move that much air.

Side note, you're towing thousands of pounds over your towing capacity so you're doing pretty good if your biggest complaint is listening to the clutch fan.

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Yep normal operation. Dash temp gauge is designed to allay your fears, not inform you. AT truck takes engine temp from oil. No PCM control of fan, strictly up to the fan clutch, so when it feels the heat it tightens up and does a whole heck of a lot more cooling. Mine has cycled on and off before but many others report continuous engagement like you. I only tow 9k. Fwiw 1200 sustained EGTs is fine. To me sounds like all is well but if you want to lower EGTs look into bigger stuff: exhaust, turbo and intercooler. Or tuning depending on what you are running now.

 

Completely normal as others said, mine does it sometimes when driving around town with nothing in the bed.

 

1250 is the red line - and I don't crowd this particular limit. One slightly inaccurate sensor and riding the guardrail can make the difference between driving and walking.

Normal operation. As mentioned before... you're 4000 pounds overweight and your biggest gripe is fan noise because your truck is sweating. I think it has earned the right to use whatever means necessary to cool off.

As stated - an electric fan won't come close to moving as much air as the stock fan. If it did, the fan would be just as loud. The driving force of the fan isn't what he's complaining about - that's the diesel. The noise is the amount of air movement through the fan.

 

If the fan's controller is using the 'push-in' thermostat, correct the reading is coming from the external side of the radiator fins. It is possible to get an thermostat that reads from a housing that is inline with the heater hose that will read actual ECT.

However, for towing, I would not consider an electric fan. When I first looked into electric fans (~ 10 years ago), manufacturer's outright stated that they could not handle combined weight levels above a certain point. Do not recall what the stated limitation was, but seeing as (at that time) I regularly was at the 14K# range and decided to steer-away, the limitation was somewhere around that point. Recent searching (about 2 years ago) did not show that same weight limit disclaimer, but seeing as the parts looked the same I do not know how they could suddenly handle the load when previously they could not.


Were I given the option, I'd consider going with an electro-magnetic fan clutch and thermostat that actuate the fan based on coolant temp and not air temp; also it will still move enough air to cool properly as it uses the OE fan. The electro-mag clutch gets the best of both worlds (cooling and efficiency), but it is expensive.



I am interpreting the "I'll be towing the RV (total weight 16k#)" as combined weight. Presuming so, how is this over gross when the manual for a '00 Ex shows Maximum GCWR 18K (trailer 10K)? If just the trailer is 16K, then yes, this is way over.


Andy, as others stated, the scenario seems normal. One thing to watch for is that during cold starts, some viscous clutches 'lock-up' for the first few miles as the fluid re-balances (my Hayden does this, but the OE clutch did not); this is normal. As long as the clutch is locking-up and unlocking in what seems an expect-able manner, all is good. The thing to worry about is if you *never* hear the fan roar.

 

The best option to reduce noise in the cab is the installation of a good stereo with a subwoofer! I found an old JL 250 watt sub for less than 100 bucks. 2-10" JL subs, and I can't turn it up without hurting my ears! Completely drowns out the single shots, 38R, and whatever noise the fan may make when it kicks on! Granted, the kids don't like Classic Country being played through that stereo, so I will on occasion put some AC/DC on for them.

 

BTW, I took the 16K total weight to mean both the camper and the truck. Being an Excursion, I assume it's not a 5th wheel camper, and I would hate to see a 16K bumper pull camper!

 

Thanks guys. Yes, 16k# total weight means both the truck and trailer. The trailer weighs about 8k. I'm well within my towing limits.

I would also love to see a 16k# bumper pull trailer.

Thanks Jay for a very detailed reply. I've noticed that mine engages when it's cold as well. Maybe it's not original.

I never realized that a fan could actually move more air through the radiators than just driving at 60mph could. Learn something every day.

 

I have yet to experience the one on my pickup coming on but on the heavy trucks that I drive you can feel the drag on the engine when it kicks in in addition to the roar. When sitting still and it kicks in I can feel the heat just pour out from under the hood past the driver's door.

 

On all of my trucks, the fan engages at start up for a minute or 2, and is really noticeable when I leave the house especially if I just get in and drive, which is what I usually do. But I never hear it again until it gets warmed up.

 

Same thing mine does!

 

I don't think mine does, now I have to check it for proper operation. Thanks for that information.