M1097 6.5L 4 speed Thermostat - fan - issue question....

[Mogman]

Also what condition are the cooler fins in?

 

[Retiredwarhorses]

If the fan is on, it’s almost impossible for it to go to 240…IMO, your fan is not engaged and you think it is.
you cant test If the fan is engaged and disengaged without leaving the driveway, while driving, you can hear the differences between engaged and disengaged, when engage, it’s like reentry of the space shuttle.
And don’t let it go over 240! Pull over and unplug the TDM to make the fan run all the time, let her cool before you make the truck back home.

 

[4x4nutz]

Try to narrow it down to coolant flow or air flow. Thermostat stuck closed or partially closed? Radiator clogged internally? Or dirty externally, inhibiting airflow? Just spitballing.

Looks like I'm getting good flow in the reservoir. No debris between radiators. Would it be a mistake to pull the thermostat out and run it without one just to check if there's any difference?

 

[4x4nutz]

If the fan is on, it’s almost impossible for it to go to 240…IMO, your fan is not engaged and you think it is.
you cant test If the fan is engaged and disengaged without leaving the driveway, while driving, you can hear the differences between engaged and disengaged, when engage, it’s like reentry of the space shuttle.
And don’t let it go over 240! Pull over and unplug the TDM to make the fan run all the time, let her cool before you make the truck back home.

I could hear the fan come on.

 

[Autonomy_Lost]

Looks like I'm getting good flow in the reservoir. No debris between radiators. Would it be a mistake to pull the thermostat out and run it without one just to check if there's any difference?

You'll get mixed opinions on this. But I think running without a thermostat for a short period of time for troubleshooting purposes is fine.

Heck, I ran a beater vehicle for almost a year with no thermostat and straight water

 

[4x4nutz]

Also what condition are the cooler fins in?

In good shape.

 

[Coug]

Have you verified any of these temps using a laser thermometer? These are notorious for the gauges to be inaccurate, or wiring issues with high resistance causing incorrect readings.

 

[4x4nutz]

The temp was right on the money yesterday when we checked it against the temp gauge.

 

[Autonomy_Lost]

Have you verified any of these temps using a laser thermometer? These are notorious for the gauges to be inaccurate, or wiring issues with high resistance causing incorrect readings.

I was thinking this too, but he said he had coolant boiling out of his overflow cap, so...

 

[Coug]

I was thinking this too, but he said he had coolant boiling out of his overflow cap, so...

Checking multiple spots and the radiator hoses would be a good indication if the thermostat is opening properly.
I've also seen what people thought was overheating/boiling coolant was actually blown head gasket putting combustion gasses/pressure into the cooling system.

 

[4x4nutz]

I was thinking this too, but he said he had coolant boiling out of his overflow cap, so...

Yesterday we verified the temp when it was around 180. It corresponded with what the gauge said (180), so when it got hot today, we did not verify again as we know the gauge is working.

 

[4x4nutz]

Checking multiple spots and the radiator hoses would be a good indication if the thermostat is opening properly.
I've also seen what people thought was overheating/boiling coolant was actually blown head gasket putting combustion gasses/pressure into the cooling system.

I was thinking blown head gasket too...will check the oil tomorrow to see if I have water in it.

 

[4x4nutz]

Leaking from behind the fan shroud.....and of course the leak stops when the motor is turned off.

 

[Autonomy_Lost]

Water pump?

 

[Mogman]

Snap a picture of the fan.

 

[4x4nutz]

Snap a picture of the fan.

 

[4x4nutz]

Checking multiple spots and the radiator hoses would be a good indication if the thermostat is opening properly.
I've also seen what people thought was overheating/boiling coolant was actually blown head gasket putting combustion gasses/pressure into the cooling system.

No water in oil...with the photo of it leaking coolant from around the fan, I guess the pump is leaking and the wind from fan is pulling coolant into the area around the shroud...pulling off the side panels to get a better look. But then again, there seems to be a good circulation going to and from the reservoir so maybe the leak isn't from the pump.

 

[Mogman]

That is the correct fan, would not have been the first time one showed up with the wrong fan.

 

[4x4nutz]

After pulling the thermostat out and running without one it ran fine. After 5 miles temp was around 190, 10 miles 210 and fan came on and went off as needed. I am considering the upgraded cooling kit. Any thoughts? Also, THANKS EVERYONE who had something to say about this issue. I can now move onto the turbos...lol

 

[Mogman]

After pulling the thermostat out and running without one it ran fine. After 5 miles temp was around 190, 10 miles 210 and fan came on and went off as needed. I am considering the upgraded cooling kit. Any thoughts? Also, THANKS EVERYONE who had something to say about this issue. I can not move onto the turbos...lolView attachment 890479

HOKUM