'17 3500 Rad cooling fan does not come on with hot engine. Bad fan relay?

[Wiredawg]

Another Point,

OP, please post a signature with your truck info. Also, is your coolant temp gauge in the red? Almost? Temps on these trucks dont compare with previous gens. They run hotter.

After all this info we provided, be nice to see some facts more than you think the temps are excessive, not saying they're not, but some of us are going to considerable effort to help.

Anyhoo, unless you want to throw parts (money) at it, I think we're at the end of how we can help without a lot more info than I cant get my fan to engage without A/C. Please understand, I'm not attacking you, we're just not sure you actually HAVE a problem.

Cheers,Ron

 

[AH64ID]

Temps on these trucks dont compare with previous gens. They run hotter.

They do run a little hotter but not much and still have the same temp limits as a 2003 did.

The only trucks that ran a lot hotter are the 10-12 trucks with the 200° thermostats, otherwise 03-09 and 13+ all use the same 190° thermostat and similar fan settings, even the cooling systems aren't that different.. aside from block capacity and the twin radiator setup in 13 for a year or two. The biggest advancement in the fan has centered around air conditioning and not coolant temps.

I know it seems like a lot should change in 15 years of advancement, but honestly it didn't. The OP's 2017 just isn't that much different than the first viscous clutch fan setup in 2003.

 

[Wiredawg]

OP ever check for codes? I see no mention of it. It's extremely important. If he hasn't, why is he working on it? Unless he likes spending money on parts throwing. Also curious as to why he's not letting the dealer work on it under warranty? Is his scan tool showing the same coolant temp as the dash? Maybe his dash is lying?

Earl

They do run a little hotter but not much and still have the same temp limits as a 2003 did.

The only trucks that ran a lot hotter are the 10-12 trucks with the 200° thermostats, otherwise 03-09 and 13+ all use the same 190° thermostat and similar fan settings, even the cooling systems aren't that different.. aside from block capacity and the twin radiator setup in 13 for a year or two. The biggest advancement in the fan has centered around air conditioning and not coolant temps.

I know it seems like a lot should change in 15 years of advancement, but honestly it didn't. The OP's 2017 just isn't that much different than the first viscous clutch fan setup in 2003.

So John, your info about thermostats temps is in direct conflict with what the 2017 OEM Service Manual states the thermostat is 200°F. When the OEM gets it wrong, its not much help.

 

[AH64ID]

So John, your info about thermostats temps is in direct conflict with what the 2017 OEM Service Manual states the thermostat is 200°F. When the OEM gets it wrong, its not much help.

Not having seen the 2017 service manual I can't comment on that (other than your photo), but I have driven 2017's and they do not have 200° thermostats.

What temp does your truck cruise at empty and warm?

Have you looked in quickserve for your thermostat specs?

 

[Wiredawg]

Friends,

I just read the thermostat thread and back through this one. Based on all that info AND what I read in the FSM info I posted, either OPs truck doesn't have a problem OR all the self diagnostics AND one or more components are in technical terms SCREWED. If there was a temp issue, a MIL SHOULD have lit.

OP and anyone wanting to work on their 4th gen truck should:

- Purchase AlfaOBD and Bluetooth reader to or similar that can read and clear codes... not going into other goodies Alfa does.

- A FSM that covers your year truck. I've done this for ever vehicle I've owned EXCEPT wifes 2019 Ram 1500, which has lifetime, unlimited mile factory warranty. 0

I have a trusted dealer I've used for over 20years and have no hesitation in using them, if needed. I still like understanding the concept of operation on my vehicles, and it helps me decide whether to DIY or go to dealer.

Also, I haven't paid that close attention to my gauges or Edge CST2 Monitor to say succinctly when my fan roars like a prop plane and when it stops, and I cant say succinctly how high any of my temps have actually gotten. Might could use either Alfa or the cool maint app that comes with my Bluetooth reader to see if that's stored and accessible from the ECM.

I'm done rambling and posted all I've found to help OP determine if he has a problem.

Cheers, Ron

 

[AH64ID]

Ron,

I don't think a MIL should have written, and I don't think the troubleshooting is screwed (thou the thermostat temp is off) but I am confident he has an issue.

He is operating above normal temps with minimal fan operation, and that's not correct. He isn't hot enough, luckily, to set a MIL or check gauges light. Nor is his fan broke hard enough to set a MIL.

I do know that if I was getting his indications, 225° and no fan noise, I would be at the dealership as something is wrong.

The links are helpful.

 

[Wiredawg]

John,

You are CORRECT and the 2017 FSM is WRONG. And my thermostat is 190°.

Unfortunately my FSM doesn't list how much out of temp the 3 sensors have to be to set a code and a MIL.

Be interesting to see how all this turns out.

Cheers, Ron

 

[cricha]

First off, 230 coolant and 240 oil temp is too hot not to have the fan on full blast. period. The fan is not on at all or just slightly. oil temp was actually measured at the filter housing and pan. accurate.
The problem is the fan is not coming on when it should.
truck runs 195-205 coolant normal around town, up and down some hills around here and 65 on the fwy unloaded.
the presented oil temp is usually 198-202 or so with the same driving parameters. measured oil temp during those times varies greatly as much as 30 degrees dur to the algorythm that calculated the temp.
I believe my thermostat should be a 200. not entirely sure, but that part of the issue was ruled out.
when the fan turns on at or around 205 coolant temp, the coolant temp drops quickly.
again, the problem is, it doesnt come on after that.

 

[AH64ID]

If you're cruising at 60 on flat ground what is your coolant temp? Should be 191°-193°. Unless your thermostat has been changed to an 200° then it's a 190° one from the factory.

Oil temp appears to be fairly accurate most the time, but it is a fake gauge. There is no oil temp sender anywhere on the motor. I ran an aftermarket oil temp gauge on my 05 so comparing the two they did a pretty good job programming it, but there are still times where it will drop 20° as you come to a stop and oil temp doesn't react that fast. Either way it's fake and can be ignored, just like oil pressure.

You need a way to monitor fan rpms and see if the fan is not increasing rpms, or not actuating at all at higher coolant temps. AlfaOBD is likely the cheapest way to do that, but something like a Edge CTS2 would do it too, and what I use even thou I also have AlfaOBD.

 

[cricha]

Ron, you have posted a ton of really good info, and I appreciate it. Truely. Im sure others reading through this might pick up some wisdom as well. After reading all of the input from both threads i believe the problem is either a sensor or the fan clutch itself. Joe had an identical problem, so there is an issue, and others are having it as well, but he didn't know what the dealer did to correct. I am inclined to think it is something fairly simple otherwise there would have been additional parts listed on his repair order that would have told him what it was. if it was a software issue it would have to be a programmable data point command such as the fan comes on when these parameters are met. I dont know if that is even a possibility.
what I know is, I dont want to be hooking up my trailer and going for a long trip until I get this sorted out.
Trying to find a shop somewhere in a large general vicinity to take it to. Looking for recommendations. I live in the Ventura, CA area.
Thanks again guys for all the input on this. If I can get it corrected, you can bet I will post the solution.

 

[cricha]

If you're cruising at 60 on flat ground what is your coolant temp? Should be 191°-193°. Unless your thermostat has been changed to an 200° then it's a 190° one from the factory.

Oil temp appears to be fairly accurate most the time, but it is a fake gauge. There is no oil temp sender anywhere on the motor. I ran an aftermarket oil temp gauge on my 05 so comparing the two they did a pretty good job programming it, but there are still times where it will drop 20° as you come to a stop and oil temp doesn't react that fast. Either way it's fake and can be ignored, just like oil pressure.

You need a way to monitor fan rpms and see if the fan is not increasing rpms, or not actuating at all at higher coolant temps. AlfaOBD is likely the cheapest way to do that, but something like a Edge CTS2 would do it too, and what I use even thou I also have AlfaOBD.

my truck ran at about 192-195 coolant for a long time when I first got it.
oil temp comments are noted and I agree 100%. I have seen the oil temp reading plummet all of a sudden. I know at lower temps it varies a lot between presented temp and actual. at 240, I have measured it accurately, and it is 237-240. its HOT.
I had a CTS in my Sometimes Duty and loved it. I might get one for this truck since i get a huge discount if I send in my old one. I did not know it would display fan speed.
I am going to get the Alfa OBD tool. maybe I can learn a bunch more.

 

[cricha]

Unfortunately my FSM doesn't list how much out of temp the 3 sensors have to be to set a code and a MIL.

What are the 3 sensors you are refering to? The shop told me the same thing, but would not say what the sensors were. THANKS!

 

[AH64ID]

The 3 sensors it compares for accuracy are engine coolant, intake air, and ambient intake air. There is a time limit, as noted with Ron's post, and there is also a wide tolerance since using the block heater doesn't heat all 3 the same and won't set a MIL.

This is another thing that is helpful to look at with the CTS2.

I really don't think you have a sensor issue thou, as the dash temp is derived from the same sensor that the ECM uses to determine fan speed.

Running 192°-195° indicates you have a 190° thermostat.

The filter housing is where I had my oil temp probe on the 05. Once warm oil runs hotter than coolant almost all the time. Cool weather with empty highway driving is about +10°, towing on flat ground is about +20°, pulling a long grade while towing will get to +25° but generally not much higher than that. If you're towing hard up a grade with coolant at 215° it's normal for the oil temp to be 235°-240°.

 

[sag2]

One could eliminate all the speculation if there was data available. The factory scan tool, and I suspect many others including Alfa OBD should read desired and actual fan speed. Once you know those two pieces of data you can go about getting to the bottom of it. Lots of good info has been posted, but at this point all speculation until the data is available.

FYI the thermostat called for on a 2017 6.7 is 68005464AB. This is the note in the 2017 parts info. Notice it is not updated for 2015+ trucks, but the PN is the same except for the supersedence.

Important!
There has been an application change to the Cummins turbo diesel thermostat.
When replacing a thermostat confirm the correct replacement is choosen. 2010,
2011, and 2012 RAM Trucks 2500/3500/4500/5500 engine coolant operating
temperature has been increased to 200 degrees requiring thermostat 68067109AA.
2009, 2013, and 2014 RAM Trucks 2500/3500/4500/5500 engine coolant operating
temperature is 190 degrees requiring thermostat 68005464AA. These thermostats
are not interchangeable and doing so will result in reduced engine performance

 

[AH64ID]

Max fan request speed for all 2017's is 4000 rpms.

 

[RammerJam]

Isn't the temperature at which the fan clutch engages set at the ECM?

I have no clue, just spit-ballin' but it seems to me you should be able to re-set that with a Dealer-Type scanner. Or maybe AlfaOBD????

Also, could it be the sending unit or could the thermostat need replaced??

Just thinking out loud

 

[AH64ID]

Isn't the temperature at which the fan clutch engages set at the ECM?

Yes, that's the temp/rpm chart I posted earlier.

 

[cricha]

Isn't the temperature at which the fan clutch engages set at the ECM?

I have no clue, just spit-ballin' but it seems to me you should be able to re-set that with a Dealer-Type scanner. Or maybe AlfaOBD????

this was what I was thinking about the issue maybe being a software issue. I dont know if those data points are changeable with the dealer scanner or AlfaOBD. I think Joe might have been thinking along the same lines. His issue was corrected without any hardware parts if I read his post correctly. does anyone know if the temp setpoints are viewable in AlfaOBD or the dealer scanning software? Im purchasing the AlfaObd program today. Anyone that uses the AlfaOBD software, which version do you prefer? the windows based or the android based?

 

[Ozymandias]

Android, absolutely.

Was your truck ever updated by the dealer?
There are updates all the time with these new vehicles.

 

[EZeis]

Android, absolutely.

Was your truck ever updated by the dealer?
There are updates all the time with these new vehicles.

Yep, and his same software was on millions of trucks. I see this thread going nowhere.

Proper complaints will get software updates done under warranty.

Earl