Driving three hours to the beach today, all interstate, light traffic (lucked out, there), the fan sounded like a jet engine at take-off...

Every now and then, it would act "normal" and quiet down, but it seemed like the fan was engaged, or making a a lot of noise.

Is there a way to test, or some idea on the situation?

Thanks in advance. Truck is a 2005

 

With gauges you can see FAN RPM versus FAN DUTY CYCLE. If the Duty Cycle is 0% and yet the fan is turning 1000+ rpm then something is whack.

Josh

 

I performed a coolant flush today on my 2006. What I know for sure. The only time my fan kicked on like a 'jet engine' was when the coolant temps hit 207. Fan remained on HIGH until the temp dropped to around 202, then went back to normal. So the question is: What were your coolant temps?

 

It's a 2005 Excursion, so gauge readout is limited to what's on the dash. Prehistoric, compared to some of the newer clusters.

If it helps, it sounds like a jet engine from the time I left the driveway, engine was cold. Never reached hot from what I could tell on the swing gauge needle, but I cannot tell the exact temps.

Thanks for any insight.

 

Fan clutch sounds stuck.

As for the "jet" sound. It can sound like that with as little as 1200 rpm fan speed, which is most likely the range one would see with A/C and only 207 ECT.

High speed is 4000 rpm.

Josh

 

He means OBDII gauges such as a ScanGuageII.

 

Before you jump on new parts. Check the harness to the fan for any
chafing. You have a 12 to the fan clutch and the PCM controls the
grounding of the circuit. So if the ware from the PCM is chafing
and grounding out you will get full fan.
You also should get some thing like the SGII ScanGaugeII : Linear Logic - Home of the ScanGauge
This will help now and later when someone asks what is the XYZ reading.

There are also other types of tools and if you have a smart phone that
may be the better way to go.

Sean

 

Truck ran hot today while going up inclines w/ AC on. Out of the truck, fan was spinning. A rev of the engine and it sounded like a jet, still.

I cannot see the wiring to see where it might be chafed, as suggested earlier. Almost like the fan wasn't working, earlier...

 

If the trucks running hot then the fan is doing it's job. You need some real gauges. Stock gauges will give you about 5 seconds warning before the truck self destructs.

 

The first step to diagnosing your issue is to have it scanned for DTCs (DTCs = Diagnostic Trouble Codes). If you get a P0528 Fan Speed Input missing. THAT, can and certainly will cause the fan clutch to randomly, but consistently run at elevated duty cycles the way you describe. In a nutshell, the PCM doesn't "know" the speed your fan is running at so it will command some default higher duty cycles to protect the engine from potential damage.

But in your case, if the engine is in fact running hot, you'll need to repair what is causing it to run hot. For what it's worth, I have seen improperly secured, or outright disconnected ECT and/or EOT sensors causing the fan clutch to run at higher duty cycles as well. With either sensor disconnected, you will not see a ZERO reading for your temperature data either. What you will see, is an "estimated" temperature data if the sensor is disconnected (and/or if there is an open in the wiring to said sensor), based on the inputs of the other sensors, as well as the vehicle's operating conditions.

 

Mike, are you saying he needs some decent gauges?? LOL.

 

I'm just running through some real time possibilities that will cause what he describes. Possibilities that I've already seen myself first hand.

 

Well, unfortunately, I was heading home from a trip and it illuminated the "Check Gauges" warning lamp. The needle was 2mm shy of the "red zone" and when I got moving on the highway, it went out, settling to midway in the gauge. It stayed that way until a few hills, which the needle climbed, lit the warning light for a few seconds, then cooled after I crested the inclines.

Coolant was low, as I checked when I got home. I'll check further in the AM, where it might have gone...

Thanks for the responses, thus far.

 

Thanks!

 

If the engine temperature gauge went into the "red zone", you obviously have some legitimate cooling system issues that would be far better addressed sooner than later. Is the water pump even flowing coolant? You can check this very easily by disconnecting the small rubber hose that runs from the intake mainfold to the coolant degas bottle, at the degas bottle end. Start the engine with the hose aimed into an empty bucket. You should see a steady stream of coolant exiting the hose if the water pump is flowing coolant.

If the water pump is flowing coolant, then your next step would be to do a pressure test to pinpoint the source of your coolant leak and repair as needed immediately before further damage is done.