I recently took a trip to CO. While in Denver driving around looking for Walmart and a place to eat the Fan Clutch stuck and fan was going warp speed for about a minute or so. It returned to quiet pretty quickly so I didn't think anything more about it. When in a drive thru line to get some quick dinner after skiing one evening I looked at scanguage and both oil and water temps were 215 or so. This alarmed me as I never see temps over 193 no matter what conditions I'm driving in. As soon as I got back on the road back to our condo the temps settled quickly to normal. I didn't have any more indications anything was wrong. On the trip back to Texas I pulled off highway to fill up and as my custom driving on trips left it running while filling up. I noticed once again that the temps were 215 or so and as soon as I got back on the highway it went back to normal quickly.

Is the fan on this truck electric and I possibly just blew a fuse? Any help would be appreciated.

 

Fan should be running at 215 ECT so it's doing it's job. It is mechanical and electric both--pretty neat design. Any degas puke/loss of coolant? Could have a tstat sticking.

 

I too think your tHermostat is sticking or your water pump impeller is not working correctly. At an idle in cooler temps, I ussually see water temp dropping below 190, even if just rolling down hill. Fan should only be on low to medium at that temp, at 218 should kick into high. Check the wires to the fan control, it's a viscous coupling. If you have scan gauge or torque pro, Fan VAR will tell you what is being commanded.

 

I would add to that this. What is the coolant level?



Sean

6.0L Tech Folder

 

The fan won't increase to "medium" speed until around 207-210 and high speed around 220F. During the winter I've noticed my truck runs warmer when idling. Haven't really let it sit for long, about 10-min but it will hit almost 200.

During the summer the truck maintains 190 idling as I'm usually running the AC which locks the fan up to "full speed" at idle for airflow across the condenser. It disengages once you get rolling, but I can hear a brief blip of the fan when I first take off. I think that keeps the temps down.

215 does seem high as the fan should be on medium speed by that point.

Sounds like a fan problem as the truck runs fine otherwise. Check the FSS on the scan guage. Normal should be around 500rpm all the time. Medium speed is around half engine speed, full speed is a bit above engine speed and is VERY loud.

How does the truck do towing or driving uphill? I had a partially plugged radiator that would quickly hit 210 climbing unloaded and run 220 continuously climbing with a trailer. Never had any problems at idle though.

 

I'm with mhoefer on this one.

 

SOME INFO ON FAN OPERATION FROM THE TECH FOLDER:
Some say fan kicks on at 210, some say 215, others say 220. Full explanation: Engine temperature is not the only parameter that the PCM monitors to determine cooling fan operation. This is the reason that you will see some variation in engine temperature as it correlates to fan operation. The operation/description of the FSS (Fan Speed Sensor) from the PC/ED manual has a fairly good explanation as to how the system "thinks". This is not your traditional engine hits temp X and the fan clutch locks up. The fan speed sensor is a Hall-Effect sensor integral to the vistronic drive fan (VDF). The powertrain control module (PCM) will monitor sensor inputs and control the VDF speed based upon engine coolant temperature (ECT), transmission fluid temperature (TFT) and intake air temperature (IAT) requirements. When an increase in fan speed for vehicle cooling is requested, the PCM will monitor the FSS signal and output the required pulse width modulated (PWM) signal to a fluid port valve within the VDF. Engine begins to defuel at 221 deg. The thermostat begins to open at about 190*F to 195*F and is not fully open until about 215*F to 219*F..

I agree the thermostat is the logical place to start, coolant level (check cold engine off) should be near ADD mark cast into the reservoir. Have you been in the mud lately? Trash in the cooler stack can build up pretty good, might want to take a look between them and wash out anything you find between the intercooler, a/c condenser and radiator. Water pump issues usuially cause higher temps at speed. A properly working system should cool off at idle not increase in temp.

 

I have been watching my gauges for 10 years, on my outlook monitor, fan speed comes up to high at 217 or 218 every time. In summer when towing, I always have AC on too. It seems as long as oil temp is up to normal operating range it ramps the fan on the temp of the water. You should definitely hear the fan on a medium stage once the temp hits 215, it will be moving air. And like posted above you should hear it when you rev the motor to start moving and then it will likely turn off once moving, but on acceleration you will hear it ramp up. If not, you definitely have an issue if is not engaging at all at those temps. Now if the outdoor temp is below 20 f I can't see how it's getting that warm idling if there is not either the thermostat sticking partially closed or your water pump having issues.

 

I'm resurrecting this thread because I started noticing problems again after almost 5 months of normal driving. Back in January when I got home from my trip I put in almost a gallon of 50/50 mix. I'm using ELC coolant. Coolant level has remained constant ever since, but starting last week on occasion when I come to a stop the A/C starts blowing hot humid air and the temps begin to climb. Pulling my boat on Saturday(4500lbs) temps were running 15-20 degrees over normal. Oil and water temp delta is still within 5-6, coolant level is perfect. This over temp issue hasn't sent temps alarmingly high, but not being able to keep the inside cool in stop and go traffic or even at a stop light is troubling. I think it is a sign that something else is wrong. I'm considering having water pump and thermostat replaced, but if I'm lifting the head gasket I'd rather not be replacing parts that are still in good working order. The four or five days before I ever saw temps above normal I was smelling coolant when I would exit the truck after driving it. I assume this is related. There is no sign of water in the oil, or transmission fluid, and no sign of oil in the coolant. I cannot smell exhaust in the degas bottle either. No signs of puking either.

 

Sounds more like a problem with the A/C that the engine.

I'll see if I can find an A/C check list. But you should have
some with the correct tools check the working pressures in
the system and compressor operation.

EDIT : What year and model is this?


Sean <BR>

6.0L Tech Folder

 

I agree with Sean.
My truck would do the same exact thing. So bad it looked like steam was coming out of the vents. The compressor clutch would also not engage. It mostly did it upon first start up. Once driving it seemed to act normal.
I then had the clutch fail so I replaced the drier, compressor, and filter/orifice tube. The old orifice tube was partially clogged.
Ever since I did that work in 2013 it has not done it since. I think it would kick out because of the pressure switch sensing high pressure from the clog.
So what I'd suggest is put a set of manifold gauges on it and monitor the high and low side to see what it's doing. You could also have a bad low or high pressure switch.

 

Do you have high idle hooked up? Not sure the A/C alone would cause ECT to spike to 215*, unless the compressor is making the belt bind somehow, but the belt should be toast by now if it were.

Thermostats tend to fail open, my initial thought reading the original post is this because of temps spiking at idle:
Edit: You have an EX? Is it the fancy one with rear climate control? Maybe it can be HVAC related since the system is different. I don't recall how exactly but there has to be more parts in there. Entire second heater core for the rear? If there's only one A/C still could be a blend door issue or heater control valve compounding bad A/C pressure.

 

TTDiesel, yes it is an EX Limited (fancy) with separate rear A/C. The first time I had the problem was in January in Denver CO and problems persisted during that trip with continually below freezing temps other than being parked most of our stay in a heated garage(around 60 degrees). I'm not sure if this makes a difference(A/C vs Heat) or not.

My daughter requests that I turn on the rear A/C as soon as she gets in the car, but when driving alone or just two of us, one of the first things I do is turn off the rear A/C. Yesterday evening doing research here caused me to take my wife for a drive to the beach and surrounding areas to see if we could get it to act up and it ran perfectly the entire time. I'll try it again after work today with the rear unit on. I'm thinking I'll find an issue there, but I'm still not sure how this would make the truck run hotter than normal.

 

How much of a bearing to condenser temps have on coolant temps? And with dual climate, is there a larger or another condenser?
I only ask since I don't have a clue. It's pulling air through obviously but I don't know if there are situations where an cranky A/C system might lead to higher coolant temps.

 

I'm not sure about the dual climate issues. I think I'm going to post this in the EX forum to see if this has been an issue with anyone else. I just ran about 45 minutes with and without the rear unit on, and different configurations of AC and Heat requests. I couldn't get it to act up in any situation. I've started a log though and I will keep an eye on it. I think it is related to the rear AC/Heat. Might me an issue with the heater core for that unit. That would explain the slight smell of antifreeze a few weeks back and losing some fluid during the winter. If anyone finds out where that heater core is located I'd appreciate you passing that info on.