2010 Viscous Fan Problem

[KOwens]

Hello TDR gurus,

Can any of you tell me when the viscous fan on my 2010 turbo diesel should begin to engage and spool up to speed based on coolant temperature?

Had a bad experience today returning from AZ to San Diego...pulling the Ocotillo grade with the outside temp at 108 degrees...towing my trailer. I was in 4th gear (1:1, 68RFE) at 60 MPH when a slower vehicle pulled in front of me and slowed down...causing me to disengage the cruise control. I then passed the slower vehicle only to have the EVIC chime and indicate a coolant over temp...which reached 246 degrees in a hurry! I backed off the throttle, and eased up the remainder of the grade to allow it to cool down. The viscous fan did not spool up during my original acceleration around the slower vehicle or during the rest of my climb up the grade...despite the coolant temperature in the high 230-240 degree range! Once I reached the summit, the engine did cool down very slowly.

Within a few miles, I encountered other fairly steep grades where the coolant temperature would rise above 230 degrees without any viscous fan spool up. Other times, it would spool up at around 220 degrees and behave like I would expect it to. Outside temperatures in this mountainous area were still around 100 degrees.

I do not have the CD service manual (yet), but plan to purchase them at this time...so I don't know the specification of when the viscous fan should engage and disengage based on coolant temperature.

Anyway, I could use your help if you can tell me when the fan should engage and disengage based on coolant temperature...so I can better understand the problem.

Thank you, Kevin

 

[Bob4x4]

The fan is computer controlled.Use of a scanner will be the best way to troubleshoot.........

 

[KOwens]

Thanks Bob4X4,

Good to know the fan is computer controlled...my '95 was viscous only! Didn't know it was changed...since it worked fine and I never looked at it closely. Thanks for that bit of information.

I do have a scan tool, but don't have the manual to tell me what the codes mean. I suppose I could Google them one at a time.

Any help you could provide to get me troubleshooting would be appreciated...like a list of probable codes I will see on the scan tool under what conditions.

Thanks, Kevin

 

[PMcCall]

try this...

http://www.genosgarage.com/GenosGarageTechArticles/TDRBG_DCTs.pdf

 

[Bob4x4]

Any codes that have been tripped should remain at least stored. There is also live data that can be monitored real time while driving

 

[KOwens]

Thanks PMcCall and Bob4X4,

Couple of things...

First, I see no wires leading to the viscous fan...none! Looks like the typical large size nut holding it to the drive pulley...and it spins freely by hand with the engine off. As a retired electrical engineer, I'm having trouble seeing how it can be computer controlled...if there is no physical connection electrically. Again, what is the standard fan configuration on a 2010? Viscous only, or computer controlled?

Second, no DTC codes have been set. Hooked my scan tool to the connector at the knee bolster...turned the key on...got a green light and the reader shows a ZERO...no codes retrieved.

Having said that...and again with no service manual at this time...what happened when the EVIC chimed and the engine temp showed 246 degrees. Didn't look good to me pulling that hill, but seems like the viscous fan should have been engaged by then...and the roar should have been noticeable in the cab...and it took a long time for the engine to cool down without the additional air being forced through the radiator cluster. I just don't know when fan engagement should occur so I can tell if the fan is bad or not.

Anyway, I have the extended warranty on the truck 7yr/100k, so heading up for service this AM. These guys have not been especially good at other problems...so my expectations are low.

I'll have to get the manuals soon, 'cause I don't like being in the dark, and nobody with the information I'm looking for is piping up from this link.

Thanks again, Kevin

 

[RustyJC]

My 2011 350/650 begins to engage the cooling fan around 215-216 degF with full engagement at 219 degF coolant temperature as shown on the EVIC. Coolant temp has always begun to drop immediately upon fan engagement, even when pulling the 5th wheel up steep grades in 100 degF ambient temperatures.

Rusty

 

[KOwens]

Hey RustyJC,

Thanks for the info. That sounds about right. After my near overheating incident, the fan did engage and disengage at about those same temperatures intermittently on the next few grades I pulled. It would work on one hill...then not the next. When it would not engage, temps would reach the mid to high 230's without any fan roar spool up. When it worked, they stayed below 220 and the fan roar was very noticeable.

Dropped the truck off at the dealer this AM...the service writer showed me a connector and harness on the driver side of the radiator...and indicated this is what controls the viscous fan engagement. For the life of me I don't see any "wired" connection to the fan itself...so I'm not sure how that works. Wireless? Man I need manuals bad.

Anyway, based on your experience and my past experience (had my '95 for 15 years and put on 287,000 miles) the viscous fan is not working properly...regardless of how it is engaged. Hopefully they replace it with one that works properly. I don't want to go through that again.

Thanks again, Kevin

 

[jhenderson]

There is an electrical connection to your fan. Crawl under the front end and look up at the fan. You'll see a metal trough that runs up to the clutch. It contains the wiring.

 

[KOwens]

Hey jhenderson,

Thank you for the information. Unfortunately, the truck is at the dealer right now (still under warranty)...so no crawling underneath at the moment. I definitely will once I pick it up. I looked from both sides of the shroud and could not see any wires...but never thought to crawl underneath and look up from below. That should be educational.

Again, thanks for the info, Kevin

 

[mwilson]

The fan on my '06 which is ECM controlled as well seems to be dogged in 100% just about 210 degrees. No question as you can hear it quite plainly. Other than that you would not even know that it even had a fan.