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Discussion Starter #1
I noticed yesterday while pulling about 11,000 lbs up a grade the engine got hot, very hot. The clutch fan never engaged where as it used to come on at a certain temp I believe. Would there be a fuse? Or something mechanically wrong with it? To think of it now I never hear it anymore at all. Sometimes on a cold engine it would run until the engine warmed up a bit too. Haven’t heard it in years.
 

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LHN...We ARE the Joneses
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Look into opening up and cleaning your cooling stack out front.
Bugs, grass, debris can collect between the coils over time, restricting the flow of air to the fan clutch....which results in no heat detected and no full lock to cool down.

Peruse thru this thread, lots of pics of what kind of buildup you can find.
Spraying thru the grille at the car wash, won't do it. It needs to be opened up some to properly clean.
https://www.duramaxforum.com/forum/how-tos-diy-write-ups/236810-how-radiator-stack-removal-install.html
 

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Discussion Starter #3
So aside from cleaning the stack. Which I haven’t, I have heard these fans can sometimes just fail and need to be replaced. That true? I’ll be doing a stack clean out soon just don’t have time....I also put new thermostats in last year in hopes to earn up the engine in these colder days. I currently have the new thermostats and a winter grille bra cover on driving highway speeds for 20 mins in 53 degree Fahrenheit and it barely gets above 185 degrees...what’s going on here? Figured it would be over heating in this weather with a bra
 

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In addition to what Hook has stated, here is my experience with the fan clutch, pulling heavy up and down mountains/grades. My truck is an LMM but yours should react similarly. My 5vr weighs 14k.

As I pull up the grade, my engine temp will gradually rise to around 230. When it gets to 230 the fan clutch engages and trust me you will know when it engages as it sounds almost like the intake of a jet engine under your hood. My fan clutch remains engaged until the engine temp returns to 190/200. This cycle repeats itself until I get out of the mountains/grades. I rarely have the fan clutch engage when towing on flat ground, regardless of outside temperature. All of these examples above are with the ambient temperature 75 to 80 degrees F.

Hope this helps.
 

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Discussion Starter #5
Yea so back years ago when I first got the trucknit made the morning sickness sound when cold, and when towing a couple fines up grades it also came on.

Thus past summer I was towing and it was over 230, truck warned engine coolant was hot, I let off and then it warned me engine over heated...I haven’t heard morning sickness fan sound in years
 

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Sounds like a cooling stack cleaning and perhaps new fan clutch may be in order.
 

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How long does it take to clean the cooling stack and flip the tranny cooler? Bout to make a road trip to Colorado haulin a trailer. Gonna replace fan clutch too.
 

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I think the only gain in moving the cooler, is when you've got an aftermarket bumper that blocks the air flow to the coil. Otherwise, the stock air slot is sufficient.
 

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Yes hook I have an aftermarket full replacement bumper. The brand is thunderstruck
 

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In my case.....keeping the stock bumper and air bags plugged in....keeps me out of 'Oops!' trouble with idiots on the road. :teehee

But I often dream of a MadMax bumper mod....for the "blip, you hear somethin'?" marx
 

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Lol. I ended up gettin my replacement bumper after I hit a deer haulin my father n laws lml on a gooseneck.
But anyways. Does anybody know long it takes on average to clean cooling stack and flip the tranny cooler?
 

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I think it's an easy couple of hours to do a good cleaning of the stack. BUT motivation and outside temp really plays havoc on my time estimates. It's MISERABLE here in the desert SW right now so it's a easy 2-3 day 4-10 sixpack job. <grins>
 

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Yeah, same here. Heat index towards 110 this weekend.
 

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Dang. Only n the 80’s now here. But that don’t sound bad. Just a couple hrs of work. Thanks MarvDmax
 

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Discussion Starter #15
Hey fellas, it’s been a long while since I started this thread, but I have taken my entire stack apart and cleaned it out, I was surprised what was in there.

While towing this summer on a hot day I was peaking close to 230 engine temp according to the factory gauge. The fan did no engage. And it also did not engage once all winter under the extreme cold temps during “morning sickness”.

When I was backing trailer into the house almost immediately after a steep grade my AC was blowing warm and smelt like engine compartment inside the cab. Never had those before
 

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i cleaned my cooling stack today. it took me about 3 hrs. My stack was not bad at all. I did not pull the radiator or drain it though. It was not easy to get the intercooler out and when I do it again next time i will drain and pull the radiator.
 

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i cleaned my cooling stack today. it took me about 3 hrs. My stack was not bad at all. I did not pull the radiator or drain it though. It was not easy to get the intercooler out and when I do it again next time i will drain and pull the radiator.
I'm gonna do mine tomorrow. I'm gonna blow em out with a long nozzle for my compressor, the use the wash wand I made to fit between the rads (hopefully).


Sent from my LG-H831 using Tapatalk
 

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AxysAssault, I did blow mine out with a compressor from the back too. There was a ton of dust blowing out. There is absolutely no space between the radiator and IC to put any kind of wand in between. I managed to get the intercooler out without pulling the radiator, but I fear it took more time then it would have to just pull the radiator too.
 

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Yea I popped the top shroud off today, then realized it's gonna take a bit more time than anticipated. I'm pretty sure my air wand will fit in between (it's like a 1/4" x 2ft nozzle), but the wash wand will most definitely not. I'll just blow it all out and hit the water from the back of the rad and hope for the best haha.

I should have done this properly when I had the motor on the floor for my head swap.....buuuut it was winter.....in Canada.



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Pretty much a waste of time trying to blow it out. Had my radiator out tried blowing first, did nothing. Laid the radiator down flat soak it down with Purple cleaner & let it sit for about an hour. Then did the rinse lather repeat. Mine was plugged in the center probably about 1/4 the surface, right where you need the airflow for the fan to work.
My fan comes on now before the factory gauge hits 210.
 
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