Hey guys, on my last tow, my engine fan stuck on high after climbing a pretty big hill towing about 11,000 pounds with the ac on. It sayed on for the rest of the trip (about 2 hours) and didn't "unlock" until the next morning after about 15 mins of driving. It was cycling fine throughout the first part of the trip. It seemed to get stuck after it was really spinning at about 2800 - 3000 rpms.

It did this once before when it had about 5k on it (22K now) in a similar situation only this time it happened during a regen going up a steep hill pulling the trailer. Same thing, didnt unlock until the next day. When I asked the dealer about it, they blew it off and said dont worry about it.

Any Ideas? I know I am a little long winded!

BTW, the temp gauge never moved from its normal position.

 

I've never had that happen. I think I'd take it to a dealer that has a dedicated diesel mechanic before it goes out of warranty. It sounds as though your dealer is just shining you on.

 

There have been fan clutch problems, I think there is a TSB on it in the tech folder.

 

most likely it is a sensor or something. That is how the all work now. I would rather of had a true clutch fan with a thermostat like the old days.

They can test it though. I agree, get a better tech.

 

There's a lot of benefits from having a computer controlled fan clutch. A traditional fan clutch can't engage to work the A/C at low speeds or assist transmission cooling unless the engine is HOT. The PCM can engage the fan at any duty cycle it needs to in order to keep the engine, transmission, EGR system, fuel cooling system, and intake air temps within the acceptable range.

Furthermore traditional cooling fans can't be monitored by the PCM, so there would be no warning if it wasn't working right.

I like my electronically controlled fan!

 

Thanks for the replies guys. I sat down with the "diesel service guy" at the dealer today to chat about the issue. We both agreed that since it can't really be duplicated, that its tough to figure out. He did request that when it does it again, to get it to a dealer to see if it is throwing a code. He said that they might be able to get a code off of it even though it doesn't activate the check engine light.

Does anyone know exactly how the fan speed is controlled? I thought I read once that water controlled the speed maybe by some type of electronic controlled flapper or baffel? Is sure does seem like something is stuck open when this happens...maybe not. The guys at the shop said that they have never "disected" a cluch yet but that they would look into it.

Thanks again

 

I think I read somewhere it is a viscous (sp?) type clutch controlled by sensor inputs. That is about all I know.

 

I like mine too, but I've noticed it coming on at startup sometimes which makes it a lot noisier while at "no wake" speed going up my street. It goes away by the time I get up the street though. Minor annoyance though considering.

 

hm.. my dealer tested my fan clutch somehow after I told them about the surprising sound.. they replaced the clutch..

no codes, they said, but some test they were able to do

sam

 

Trying to find a thread regarding "fan clutches" - hope this will generate some response.

My 2008 F350 is now going into it's 5th week at the dealer. You wouldn't believe all the "excuses" I have been given about what is occurring and what has been replaced. The latest, and probably the last effort by FORD, is a stuck fan clutch - this will be number 4. The third one only lasted 400 miles - all dealer driven miles.

I saw some mention of this being a electrically controlled fan clutch with a viscous fluid used to control the fan speed. This is what the service advisor conveyed to me yesterday that when the computer senses the fan needs to be engaged there is an electric current that is provided which causes the fluid to change viscosity and allow the fan to speed up to cool the engine. Apparently mine becomes stuck and will not release.

The FORD engineer is supposed to be researching the OASIS data base to try to find previous occurrences and what was done to remedy the issue. I'm not confident that they will find anything at this point based on the past 4-1/2 weeks of trouble shooting. FORD conveyed to me yesterday that this is how the engine performs and once the fan clutch is replaced they don't plan to go any further.

This all started with my truck loosing power while climbing from roughly 2000 to 5000 feet over roughly 40 miles (no trailer attached). Apparently the FORD engineer is stating that when the engine temperature reaches roughly 1310 degrees the computer puts the engine into "Reduced Engine Power" mode which majorly reduces the boost to keep the engine from self destructing (had that occur with a 2003 F250 inwhich the turbo blew and took out the motor with <5000 miles on the truck). So far they have replaced turbo's, DPF, multitude of sensors, theromostats, fan clutch (2), etc to no avail. After all these parts were installed, when they take readings while driving, they claim the engine is acting per spec.

FORD definitely has issues with the 6.4L but does not want to own up to it and just wants to put the truck back in running condition and send me on my way.

Anyone have any information on what might be causing the fan clutch to get stuck so I can pass it onto the engineer since I doubt he will be able to figure it out. I have seen other threads with responses from some FORD engineers and dealer service technicians so hopefully someone can help. I have a brand new 5th wheel just sitting for the past two months due to this issue. (Sorry to sound a little pevied but you spend your hard earned dollars to get this type of product and not want to own it).

 

I had my 08 fan clutch replaced 18 months ago or so. It was replaced under my extended warranty. I had bearing grinding noise when I turned it off. The fan was free wheel spining and soundedl like a dry bearing. Ford replaced the clutch assembly and the fan. Works like a charm now.