[sourdo]

2021 2500 6.7 L CTD, 11,000 miles on it.

Since new and not all the time, when cold the engine fan clutch, sometimes, kicks in and out every few seconds while warming up, then will operate normally when warmed up. Even in winter.

But lately the fan can really howl, and usually when it's cold, but not always.

I realize it is warm outside, and with the AC on, this may be normal, but it don't sound normal as the fan noise can be quite loud. I don't get the noise when still warming up. Does the fan kick in to help warm the truck?

A few days ago coming back from camping and towing the RV, we stopped and I left the truck running, and the fan engaged as it should while idling.

There are no codes. And this is intermittent, not all the time, sometimes not even every day. When the fan is engaged, it is noisy.

I've done some searching on the matter, and it this don't seem to be a common issue with the 5th Gen CTD.

There is no sense taking it to the dealer as there are no codes.

Any ideas? Thanks.

 

[Joe mama]

My 2020 CTD has done this since I've had it. When it's cold and I leave my driveway the fan roars for about 1/2 mile of driving. Very rarely do I hear it when the truck is warm.

 

[Captainmal]

Same here.

Mine is rarely very cold as it only gets down to maybe 75 degrees in the morning here in summer. Still, in a few minutes I am heading to church and it will sound like a turbo stuck. Just seems that for maybe 1/4 mile, sometimes less, if I go slowly there is a rather loud fan noise. Now if I accelerate strongly, which I rarely do cold, it will go away.

Always wondered about that and you are the first to bring that up.

 

[Crash68]

I think it's a quirk of the vehicle/engine as I've read about a few people on other forums stating the same thing about the fan noise when cold/first start of the day.

 

[Haul N Grass]

My 2016 did the same High Rpm start up since new , The Steel exhaust crossover pipe goes from exhaust manifold directly behind the Radiator fan into the intake I believe it’s Cummins engineered/ Programing design to help Cool the exhaust gases temperatures to lower the amount of hot exhaust gases introduced into the combustion chamber by lowering combustion temperatures to help lower NOX gases….It’s Just A Guess 😊

 

[sourdo]

Thanks for the replies.

"Sounds" like all is normal, the truck runs great, I'll not worry about it.

 

[sourdo]

When I had that Z20 recall flash for the ABS system last month, the fan howling picked up, but has this last week settled down. And the AC just rips now to my delight. I mean frosty cold when it used to be somewhat weak and pathetic.

I also noticed the "Lie-O-meter" mpg display is different, when I now go to zero it, it flashes zero, then returns to a value close to what I was just driving. And I won't know until I fill up again, but the mpg seems to be closer to reality, around 19 mpg, not 21. The EVIC display was frequently showing 1.5 mpg more than hand calculated.

So who knows what else was tuned up with that recall, I can find no other references on that.

Maybe the truck had to relearn?

Anyway, all's well that ends well.

 

[Captainmal]

Air conditioning in Alaska? Guessing you are still trying to move to the lower 48 where you should need that cool air more.

19 - 21 is real mileage for me running around locally but avoiding urban areas, shopping, idling to wait for the wife and ... It is hard not to have to wait and wait and wait.

 

[MAS]

I’m pretty sure every mechanical fan clutch I’ve ever been around came on at cold start. I always figured it added a little load to help warm the engine?

 

[sourdo]

Air conditioning in Alaska? Guessing you are still trying to move to the lower 48 where you should need that cool air more.

These last few years have seen quite a jump in summer temperatures, the climate is changing up here before my eyes.

It used to be to see an 80 F day was a rare and wonderful thing in Alaska. And not every year either.

Today? All the time and for much of June this year was in the 80,s. My lawn is yellow and dry, the leaves are hanging limp, it hasn't rained more than an inch since the first of April. We went camping two weeks ago, dry camping along the Klutina River, usually quite nice. For three days we just smelted in mid 90 F heat without AC. We do have solar, and that Fantastic fan was running full time! Man was it effing hot, but the interior of Alaska is like that with 20 hours of sun. But lately things have been over the top.

 

[sourdo]

I’m pretty sure every mechanical fan clutch I’ve ever been around came on at cold start. I always figured it added a little load to help warm the engine?

I had a similar thought. In the cold winter months, this Cummins sure warms up fast, and the fan is engaged at first start. I'm going to blame that recall flash, that is when it started. It has calmed down quite a bit since with some time and driving.

 

[sourdo]

This whole engine fan noise has completely gone away. Good, I like trucks that fix themselves.

The Lie-O-Meter is still crap. It said 20.8, HC said 17.9. That is messed up man to worthless.

 

[Ramguycalifornia]

FAN CLUTCHES ARE COMPUTER CONTROLLED AND HAVE BEEN FAILING . ALSO DUSTY TRUCKS CAN FAIL MORE OFTEN .HAVE REPLACED A FEW CLUTCHES FOR THIS . COULD BE OTHER ISSUE BUT TECH WILL LOOK AT COMMANDED VS ACTUAL AND PERFORM FAN CONTROL TEST .

 

[sourdo]

FAN CLUTCHES ARE COMPUTER CONTROLLED AND HAVE BEEN FAILING . ALSO DUSTY TRUCKS CAN FAIL MORE OFTEN .HAVE REPLACED A FEW CLUTCHES FOR THIS . COULD BE OTHER ISSUE BUT TECH WILL LOOK AT COMMANDED VS ACTUAL AND PERFORM FAN CONTROL TEST .

The whole fan routine has calmed down completely weeks since I had that ABS recall/flash done to the truck over a month ago. I don't much hear the fan anymore, though restarting a hot truck, say at the store, will cause the fan to run a bit harder, no doubt because the engine is heat soaked.

I would say all is well and fine now.

 

[Dieseldragon]

The whole fan routine has calmed down completely weeks since I had that ABS recall/flash done to the truck over a month ago. I don't much hear the fan anymore, though restarting a hot truck, say at the store, will cause the fan to run a bit harder, no doubt because the engine is heat soaked.

I would say all is well and fine now.

Hi: sourdo... Glad to know you finally got through to your noisier fan!!!
Dieseldragon North shore of Lake Erie.