Running temp for an LMTV

[Third From Texas]

Maybe I missed it. in a message... but does your fan come on? You would know they say. Loud as hell.

Yeah, he confirmed that fan is working to spec.

 

[waynegpugh]

I doubt the winch is blocking much, as there is plenty of room for air to get around in behind under the intercooler. These trucks have horrible natural rolling/ram airflow and the fan is a necessity when you are making heat. With the truck turned off, the fan should be locked and you should be unable to turn it by hand. As mentioned, should be a loud roar when the fan engages… if the air tanks are full, if you turn on the ign switch, this should power the fan control solenoid and send air to the fan clutch, you should then be able to spin the fan freely by hand(wiggle it front to rear also to check the freewheel bearings).

Were you getting a high coolant temp or a high trans temp light in the dash. There is a temp switch in the thermostat housing that turns on the coolant temp light at 230F. The trans controller has a programmed output contact that should light the trans temp warning light at ~220F oil temp. A handheld IR tempgun can help you to confirm the gauge is reasonably accurate, but if you were getting 230-240 temps indicated, you should also have had at least one idiot light…

next as suggested, I would foam the radiator let it set for a bit and hose out all the air passages. this is probably easiest if you pull the upper fan shroud…

I would also drain out a couple of gallons of coolant and remove the elbow on top of the thermostat housing and inspect the thermostat. If you are that far in, probably best to just go ahead and replace the thermostat It is a bypass type,, which closes the bypass port as the thermostat port opens to allow flow to the radiator. On a 3116 the bypass port sends all the coolant to the trans cooler/heat exchanger, so if it is not fully closing the bypass, any coolant leaking that way is not getting pushed thru the radiator…

The highway gears should actually help you. Pumping load thru an engine increases with RPM. Any time you run an engine past the peak torque point, its like driving with an exhaust brake on. Your available torque output drops by nearly half between peak torque(1550RPM) and max governed RPM(2600).

and of course a little added load goes a long way to increasing engine and trans heat output. Are your hubs and drums all the same temp after a highway run?

Thanks for the great info. Not sure on the temps as I don’t have an IR gun. Sounds like I have to get an IR gun though. So I’ll be picking up one of those and I’ll be getting new thermostats. Someone else told me to deform the radiator too. So I’ll be adding that to my list to do. I think that covers it for not I’ll order those thermostats tomorrow and let you guys know how goes. Thanks again

 

[Ronmar]

Thermostats? There is only one for the engine… the 6X tractors with the auxiliary transmission coolers have a thermostatic control valve in the oil plumbing that decides if it wants to send fluid to the secondary cooler found on those tractor models, but the 4X4s only have an engine thermostat…

Thermostat P/Ns for the 3116:
119-3075 178F
115-4223 190F
126-5869 200F

They came with a 178, but I swapped mine up to a 190. But I also reconfigured my cooling system back to the way Cat intended so it now warms to op temp in a more predictable fashion.