2017 3500 6.7TD thermostat replacement

[OLEJOE]

I don’t know how to post a link but there is a TSB on it 18-061-20 that came out August 7th this year. My truck was at the dealer September 4,2020 for a abs light and HCU replacement. I tried mine out today by running it at 1500 rpm with the radiator blocked. At 205 degrees the engine fan engaged and immediately dropped the temp. I asked them to check for any issues while they were doing the brake repair and I guess they did. Engine fan did not work before it went to the dealer but it is working now. The fan clutch was replaced a year ago.

 

[BigPapa]

https://static.nhtsa.gov/odi/tsbs/2020/MC-10180252-9999.pdf

 

[Ltngdrvr]

https://static.nhtsa.gov/odi/tsbs/2020/MC-10180252-9999.pdf

What does that have to do with the issue in discussion here???

 

[DonFitzwater]

What does that have to do with the issue in discussion here???

Nothing from what I read in the TSB....but there is a blurb about fan actuation during test fix.

 

[BigPapa]

What does that have to do with the issue in discussion here???

I don’t know. I just posted the link to help poor OLEJOE.....

 

[cricha]

I appreciate all the replies, thank you. all of you are being way more helpful than any service person i have talked to. However, I am getting absolutely nowhere with trying to correct the issue, which is that the fan does not come on when the engine gets hot. You can hear the fan cycle on with the a/c, and initially when coolant temp gets up to about 205, but nothing after that. one shop mechanic said the fan works just fine, but didnt know why it wouldnt come on when coolant temps got north of 220. just call a dealer out my way and inquired about the flash mentioned earlier in the thread. dealer said he knew nothing about any flash that would help engine temp or fan control. So my questions are:
Anyone know of a good , reputable dealer or diesel shop in the southern CA area? preferably around the Ventura area, but im open to drive if i need to. THANK YOU!!!

 

[cricha]

so I found something that may be connected with my problem. I found 2 relays, one for low speed fan operation, one for high speed fan operation. there are three identical relays in the fuse box, so I swapped the high speed fan relay with the air susp relay (i dont have air suspension). Also, what is the RAD FAN PWM (F01) fuse for?

 

[AH64ID]

I thought those fan relays were for the Hemi trucks with electric fans.

The PWM fuse is likely for our trucks as the fans use pulse width modulation to achieve the desired rpm.

 

[cricha]

I don’t know how to post a link but there is a TSB on it 18-061-20 that came out August 7th this year. My truck was at the dealer September 4,2020 for a abs light and HCU replacement. I tried mine out today by running it at 1500 rpm with the radiator blocked. At 205 degrees the engine fan engaged and immediately dropped the temp. I asked them to check for any issues while they were doing the brake repair and I guess they did. Engine fan did not work before it went to the dealer but it is working now. The fan clutch was replaced a year ago.

what dealer did you take it to?

 

[cricha]

OK guys, finally had a chance to get my truck back out on the road towing my trailer. Same issues, high temps, no cooling fan, NO codes, either hard or soft. Came back home, ordered new t-stat and fan clutch. t-stat test before install, old t-stat only opening halfway, new t-stat opening all the way using a pan of boiling water and thermometer to check operation before install. Road test, temps controlling a little better, still not anywhere close to what it should be, still too hot, fan only spooling up partially. Changed fan clutch next. road test. prior to changing fan clutch, highest fan rpm achieved was ~1600rpm at 226F (if it came on at all). New fan clutch, getting 2300rpm@ 228F, when the fan comes on, but when it does, it doesnt stay on very long, temps dont come down very much. Fan RPM STILL WAY TOO LOW for engine temps and fake oil temps at 240. Still no codes of any kind. high oil temps measured at filter and oil pan using a high quality heat gun. oil temps actually at ~240f. TOO HOT. All sensors and wiring in good shape. The ONLY thing I believe it could be at this point is corrupt software controlling the fan, or, the software is not set correctly. 2 dealers refused to do a reflash, as they said the dynamics would have to recreated and they would have to verify them. the only way to verify the issues is to hook up the trailer and go for a drive up a long grade, this would take hours, dealer refused. there is a setting for fan clutch control in the AlfaOBD program, that another member has changed with partial success, but Im not going to change any program settings unless I know what it actually is supposed to be. I am of the opinion that reflashes can only be done by a dealer. Correct? if so, anyone have any suggestions on a reputable dealer in the Southern California area?

 

[Cummins12V98]

Gates is not OEM.

Lots of people have good luck with gates, but I prefer Cummins thermostats... just don’t buy them from FCA. Go direct to a Cummins dealer or on the internet.

YEP, I would NOT use a Gates Thermostat or Water Pump!!! CUMMINS all the way.

 

[josephc1]

Following

 

[Wiredawg]

YEP, I would NOT use a Gates Thermostat or Water Pump!!! CUMMINS all the way.

Agreed and would add only using MOPAR or Cummins tensioner to that short list.

 

[dpotter]

For what it's worth, at 217 degrees I can hear the fan real loud and the temp gauge drops to about 207 before it turns off. This it driving uphill, pulling a 5-6K pound trailer with ambient temp over 90 degrees at 60+ mph.

 

[Wiredawg]

For what it's worth, at 217 degrees I can hear the fan real loud and the temp gauge drops to about 207 before it turns off. This it driving uphill, pulling a 5-6K pound trailer with ambient temp over 90 degrees at 60+ mph.

Yep, both my 2017 Ram 5500 and my 2020 MH with 6.7L Cummins sound like a Cesna at full power. Very strong cooling capability.