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Cooling fans commanded/overheating towing


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2016 6.2 112k near flawless miles,towed a lot ,recently towed 7k over the long haul mountain pass,she got to 240* near the top,cooled down going down the other side.Never did hear the fans roar.The next day I disconnected the tempo sensor to test,the fans revved as they should.Put the HP tuners on it,pids show fans 1,2,3 they show off the whole time logging although they show running 25%

 

Today I put HP tuners on my 2014 truck,it shows fans 1.2.3 and fan 1 is showing running the entire time.Hoping a guru can help me figure this out,at the point to swapping fan assembly's.Thanks fuse's are good ,no CEL

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2 minutes ago, gonzoid said:

2016 6.2 112k near flawless miles,towed a lot ,recently towed 7k over the long haul mountain pass,she got to 240* near the top,cooled down going down the other side.Never did hear the fans roar.The next day I disconnected the tempo sensor to test,the fans revved as they should.Put the HP tuners on it,pids show fans 1,2,3 they show off the whole time logging although they show running 25%

 

Today I put HP tuners on my 2014 truck,it shows fans 1.2.3 and fan 1 is showing running the entire time.Hoping a guru can help me figure this out,at the point to swapping fan assembly's.Thanks fuse's are good ,no CEL

Don't think you have a problem with the fans, it is the way they are programmed to run, keeping the engine temps around the 210 range for fuel economy. 

There are posts here on the site where members have reprogramed them to run run at a higher rate of speed.

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you might have to upgrade the OS to manipulate the fans and temps to your desired value, call either the tuning school or HPTuner forum. 

 

hint** you can trip the cooling fans to come on by setting the AC to coldest setting and highest fan speed, this is done to cool the ac condenser, so it bypasses the engine fan logic, but i doubt it runs 100% duty cycle probably 50% is more like it

 

makes me wish i could adapt the 6.0 water pumps pully and mechanical fan off a 2500 truck

 

if your fans are on the entire time you either have a stuck open thermostat or the AC is switched on

Edited by pokismoki
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12 hours ago, gonzoid said:

2016 6.2 112k near flawless miles,towed a lot ,recently towed 7k over the long haul mountain pass,she got to 240* near the top,cooled down going down the other side.Never did hear the fans roar.The next day I disconnected the tempo sensor to test,the fans revved as they should.Put the HP tuners on it,pids show fans 1,2,3 they show off the whole time logging although they show running 25%

 

Today I put HP tuners on my 2014 truck,it shows fans 1.2.3 and fan 1 is showing running the entire time.Hoping a guru can help me figure this out,at the point to swapping fan assembly's.Thanks fuse's are good ,no CEL

I had my tuner change my fan control to this:

 

 

NewFanProgramming.jpg

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Thanks for posting,my question to you,when logging your fans do you fans 1,2 , 3, and does fan 1 always show ON?

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I haven't 100% verified it yet but I think the temperature gauge is fake in our trucks or at least seems "filtered" near 210F.

 

Check your coolant level, radiator has known issues with pinhole leaks you won't see until the coolant is gone.

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I had a similar problem with a car I had, it was a flat lander car and when I visited the rocky mountains and got up over 6K ft., the normal dual fan operation would no longer cool the rad., and by the time the "Second" fan was commanded, it was to late, overheating took place. I had the "Jumper the relay" on the second fan to keep it running all the time, then I could go all the way to 12K ft.  Another "interesting" event I noticed, sometimes the incline was so steep, I had to keep it in low gear, and some times,(fuel injected car) I would notice that my accel. pedal was on the floor sometimes creeping up at 25 mph. when above 10K ft.  (Rocky Mountain National Park)

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  • 4 weeks later...

Tuner went with a more aggressive fan settings,i towed again,temps came up again,not quite as hot.Yesterday I swapped in a new ac delco thermostat,took it out and drove it empty on flat ground,cruise at 207*,temps would fluctuate more than I think they should.

 

When I would do a WOT pull,say 0-85mph,temps would shoot to 229* then cool right back down,anyone seen this?you know the passenger side of radiator doesnt feel all that hot.Thanks

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On 8/30/2021 at 10:09 PM, ic3man5 said:

I haven't 100% verified it yet but I think the temperature gauge is fake in our trucks or at least seems "filtered" near 210F.

 

 

I have one of those Bluetooth OBDII readers hooked up as I was checking out some other sensor readings. I also was monitoring the coolant temps. What I noticed was that once warmed up, the dash gauge would go to 210 and pretty much stay there with 0 fluctuation. However on the OBDII reader, I saw a 20⁰ swing either way. The sensor would sometimes show coolant temps almost down to 190⁰ when just cruising level roads and sometimes up to almost 230⁰ during heavy acceleration or possibly traveling up grades. Once it did start moving upwards from 210, real time coolant temps were north of of 230⁰ already....

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3 hours ago, gonzoid said:

Tuner went with a more aggressive fan settings,i towed again,temps came up again,not quite as hot.Yesterday I swapped in a new ac delco thermostat,took it out and drove it empty on flat ground,cruise at 207*,temps would fluctuate more than I think they should.

 

When I would do a WOT pull,say 0-85mph,temps would shoot to 229* then cool right back down,anyone seen this?you know the passenger side of radiator doesnt feel all that hot.Thanks

Completely normal. My truck does the exact same thing on a new thermostat. My cruising temps are 209-212 and a long wide open throttle pull will go to around 220-230 and nose dive right back to normal when I coast/brake back down to normal speeds.

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3 hours ago, CamGTP said:

Completely normal. My truck does the exact same thing on a new thermostat. My cruising temps are 209-212 and a long wide open throttle pull will go to around 220-230 and nose dive right back to normal when I coast/brake back down to normal speeds.

 

4 hours ago, mikeyk101 said:

I have one of those Bluetooth OBDII readers hooked up as I was checking out some other sensor readings. I also was monitoring the coolant temps. What I noticed was that once warmed up, the dash gauge would go to 210 and pretty much stay there with 0 fluctuation. However on the OBDII reader, I saw a 20⁰ swing either way. The sensor would sometimes show coolant temps almost down to 190⁰ when just cruising level roads and sometimes up to almost 230⁰ during heavy acceleration or possibly traveling up grades. Once it did start moving upwards from 210, real time coolant temps were north of of 230⁰ already....

 

So the question is what is the acceptable max temperature for the L83? Is there an actual spec from GM? I know 220F is generally okay but above 230-240F seems like you are starting to push it.

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I don't know what the actual specs are but GM says that as long as the temp gauge stays out of the red (260⁰ or higher), you are OK. There will be a warning that comes up that says engine overheated idle engine or engine overheated stop engine. IIRC, if either message shows up, it will go into a reduced power mode. I have not seen mine go that high yet but it has gone upwards to just over 240⁰ when towing up grades in hot weather. I personally don't like to see higher than 220⁰ and try to keep it lower even if GM says some higher temps are acceptable. When I do see the temps start climbing to higher than what I am comfortable with, I will shift into "M" and then drop a gear or 2 to get the RPM's up and that usually helps quite a bit. 

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have you tried installing the larger radiator from the 6.2 or maxtow option?. 5.3 trucks has a puny v6 radiator that is impressive for it's size, but easily maxes out cooling capacity when towing. I will be upgrading soon. 

 

if you got a tuner , try installing the upgraded OS for the cooling system via HPtuners, it gives you more control over the fan temps, also try running a 160 stat for summer towing.

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No operating system upgrades on 2014+ trucks.

 

I'd say that going over 240 is where I'd backing it down. At this point I'd be wondering if my coolants boiling point is coming into play depending on age of the coolant and my radiator/expansion tank cap is working as it should to keep my boiling point above 250 degrees.

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