[Dale_K]

Some GM cars have a "camel mode" that lets them operate without any coolant for a few miles but I've never heard of it on a diesel. I think the GM system shuts down the fuel injectors on half the cylinders and the air pumping through them pulls some of the heat out. This is from the 2005 Corvette owner's manual...

If an overheated engine condition exists and the
messages COOLANT OVER TEMPERATURE and
REDUCED ENGINE POWER are displayed, along with
the Check Engine light, an overheat protection mode
which alternates firing groups of cylinders helps prevent
engine damage. In this mode, you will notice a loss
in power and engine performance. This operating mode
allows your vehicle to be driven to a safe place in an
emergency; you may drive up to 50 miles (80 km).
Notice: After driving in the overheated engine
protection operating mode, to avoid engine damage,
allow the engine to cool before attempting any
repair. The engine oil will be severely degraded.
Repair the cause of coolant loss, change the oil and
reset the oil life system. See Engine Oil on
page 5-14.

 

[slagburn]

What do the wires go to

They go to the electric fan clutch, there is also a sensor that is supposed to tell the ECM when the fan isn't spinning at the proper speed so it is interesting that the fan wasn't turning and that no DTC was set as a result.

 

[Flattman]

If you don't have a mechanical problem, this might explain what's happening. This is an excerpt from: TSB-18-013-08
GROUP: Vehicle Performance
DATE: March 13, 2008

1. The latest ECM software includes a new extended idle feature to accommodate the
extended idle times present in some duty cycles. This feature may help to reduce the
accumulation of soot in the exhaust aftertreatment system when the engine is idling for
an extended period of time. Briefly how this feature works:
a. As needed, the engine enters an idling mode which dramatically reduces the rate of
soot accumulation in the diesel particulate filter (called “Net Zero”). Further, under
extended idle periods of longer than 2 hours, the engine enters a mode which
reduces the amount of soot accumulated in the diesel particulate filter (called “Net
Reduction”). While in these modes, the idle speed increases to 900 rpm for a period
of time. The idle speed may return to normal idle speed and then return to 900 rpm
to repeat this cycle during very long idle periods.
b. These modes occur automatically provided two conditions are met. The vehicle
must be in Park (automatic transmission) or have the Parking Brake engaged
(manual transmission) for these modes to be enabled. There must also be no
accelerator pedal input.
c. After extended idling, if operation of the engine consists of light loads for short
periods of time the engine will return more quickly to the Net Zero or the Net
Reduction mode of the extended idle operation feature.
d. After extended idling, if operating the engine consists of higher loads for longer
periods of time the engine must again idle for an extended period before the engine
will return to the Net Zero or the Net Reduction mode of the extended idle operation
feature.

Not sure if that's what's happening in your case, but it sounded like what you might be experiencing.

 

[SpinEmNSmokeEm]

Well the truck ran fine today no high idle and no overheating. Now I just wonder if the clutch fan burnt up or not. It is on when I look under the hood and no overheating while empty and a little under load (3-4k). I have to pull my skid loader in the morning so I will see how it does then. Is there a way to test the clutch fan to see if it is weak?

 

[ruidosododge]

i think i had the same problem as you... it tore a hole into the radiator i believe... it was a while ago... one dealership said that my tuner caused it and 500 dollars later that they wouldn't give back to me I had another dealership take it right away and warrantied it... my a/c wouldn't blow cold air and it just seemed like their was a lack of power.. keep us updated.. ill try to find the receipts to see what they replaced

 

[Moparxx]

Same problem

I had the same thing happen to me a few months back. Came home from out of town and her a strange noise when I started the truck so I opened the hood and looked to my surprise I didn't see anything obvious two days later I was pulling my fifth-wheel and noticed that the temp seemed high so I called the dealer and they told me that it was the extra weight that was causing it LOL. I wasn't buying that because I had done lots of towing and never had any issues.
Any way long story short the noise that I herd that morning was exactly what you stated the wires that are running up to the front of the fan had come loose from the bottom of the shroud and the fan chewed them up. So I took it to the dealer and showed them. I'm still not sure how the clip came loose from the shroud or why Chry would put them there. Anyway sorry to go on so long but it sounds to me like the same issue that I had.

 

[SpinEmNSmokeEm]

I did loose my a/c also when it first happened. Mine didn't get chewed up but bent it and I did get it bent back but I do need to check it again and make sure it hasn't come loose. I might even put a zip strip on it to help hold it. I told the service manager when I called to cancel my appt and he asked if it pulled out the wires and I told him no, then he asked if it burnt up the clutch and I said the fan is working so I guess not. So far so good, pulled the loader fine today so I guess I have to keep driving it. I have noticed that I am getting better milage though, 13-15 up from 11-12.5. Only 36k on it I guess it is about time!:w:

 

[Ramtech]

the fan clutch (55056990AC) is controlled by the ecm. it is basically used more under heavy loads or high heat. I'VE REPLACED A TON OF THOSE WONDERFUL IDEAS. watch out, the blades on that booger are very sharp.

 

[sfd74]

I dug up this old thread- my wires have also been chewed up in the fan- I gat a low fan speed code-question- what would happen if I replaced mine with a mechanical clutch fan? $300 vs $40

 

[clovelady]

Mine had a similar problem. Temps were good most of the , but when pulling my 5th wheel (18000 lbs) the engine temp would rise, or just when driving unloaded in the summer months. Had dealer check the fan and they said it was OK. Engine never ran hot but it would get pretty warm. Turns out the fan clutch was free wheeling the fan and never would lock up. Never got a code. I purchased a new fan clutch on E-bay for $120.00 (dealer wanted $350.00) installed it in 30 minuets and now the engine temps are normal. Don't trust your dealership unless you know for sure they have a quality diesel mechanic that cares about his work.

 

[jmcirvin]

can anyone tell me roughly how many miles these clutches are good for? I imagine there could be a lot of variables but just an idea im having same trouble with 05 dodge

 

[CatDiezel]

Well, as far as mileage goes on longevity.

Im going to say 24,765 miles.

Mine is not completely free spinning but it wont engage when im pulling a trailer. Temps get up to 210 if I dont watch what Im doing.

I have a mechanic at the dodge dealership (who is a great guy) waiting on me with a new clutch at 8am tomorrow morning!!

:doh: :banghead:

The dealership I use is so easy to work with... I actually love them to death.

Heck, They let me change my own infinity speakers out in their shop under warranty for the second time just so I didnt have to wait today!!

LOT BETTER THAN WAITING.

And I will be helping their Diesel Mechanic tommorow morning install the fan clutch in their shop as well.

 

[meetsdiesel]

I noticed in my 2000 CTD that the fan sounds like it is working 5 mins after startup. When the engine is at normal operating temps, usually 180-190 I never hear the fan running. Correct me if I am wrong but shouldn't the fan work at those temps? By working I mean you can hear the roar of the fan when you step on the accelerator after a stop. Take for example a big rig that is idling and all of a sudden you hear the loud roar as the fan kicks on and runs for while.

 

[klewis3935]

fan clutch

catdiezel how did you know it wasnt kicking in I put a 180f thermostat in my 08 6.7 and it is hitting 208 in east texas 103 degree heat I know it kicks in with the ac but don't know if it is kicking in at highway speeds how do I check it

 

[Dieselman1017]

vistronic fan clutch

You need a scan tool to check it and voltmeter. I think its one of the better ideas they have had in the last few years. They are very efficent and only come on when needed. I know they have had a problem with the wiring harness coming loose hitting the fan and radiator and ripping wiring out of Fan clutch. I just replaced one the other day. There is a speed sensor built in the clutch for the ECM to monitor fan speed. It moniters ac pressure and coolant temp, Intake air temp. It runs the fan according to those readings. With a scan tool you can command it to run up and down. So if its hot out you should be able to turn ac on and wait to here if the fan starts turning faster at a idle. Hope this helps bear with me new to the forum.