Unplugged TDM

[Videris]

HMMWV was running hot 235-240 range. While TDM was hooked up.
Unplugged it she ran at 195-200 range on highway freeway wherever for 2 plus hours no issue. I don't want to run it like this all the time for obvious reasons so I was thinking that at least one of you have experienced this before and might have a specific fix. What I know is it doesn't overheat just runs to hot for my liking, gauge is well grounded and within functionality range if you will, coolant is clean and green, no antifreeze in oil, no coolant leaks and fan does kick on and off but doesn't do so until 220 range and never really keeps temperature lower than 235ish. That's when I disconnected TDM and it ran obviously cooler 195ish. Any specific fixes or ideas would be much appreciated. Thanks

 

[juanprado]

Unhooked, the fan runs all the time. Sounds like the TDM is bad. Is the bottom gooey and melted epoxy? That is what mine looked like. Easy to pick up on flea bay

 

[Videris]

Didn't even look at it that hard. Figured it was working ok because when it was hooked up fan did kick on and off at I guess the correct intervals. I will scope it out closer though. Thanks for the heads up man I appreciate it.

 

[Retiredwarhorses]

While this topic has been beat into submission for the 1 millionth time....here it is again.
the gauges are notoriously off in there accuracy, the best bet is to check the actual temp of the coolant with
a thermometer. Your 220 reading is more likely 210-215....I own 4-5 hmmwv's at any one time, they all reflect something different on the gauges and act a bit different frm one to the other on the fan operation temps.
The 210-215 is the temp the thermostatic switch is set to deny 24v to the TDM thus turning on the fan.
these are deisel engines folks, not gas engines....Diesels run hotter, that's how they work.

 

[Retiredwarhorses]

Unhooked, the fan runs all the time. Sounds like the TDM is bad. Is the bottom gooey and melted epoxy? That is what mine looked like. Easy to pick up on flea bay

Unplugging the TDM would engage the fan...so this would be a properly functioning TDM.

 

[Videris]

I hear you on this topic being beat to death. My intention was to present my specific issue to you guys (the experts) to see if maybe recently someone went through my exact situation and came up with a specific fix. I will definitely try the thermometer test but I know it ain't the gauge directly because I don't just have a high reading I have engine fatigue at those high readings so it's something else. Have any of you had radiator re-cored? I figure I'll replace all the usual suspect parts (TDM, thermostat, Cadillac valve, etc.) as well as recore radiator. Other than the fan clutch assembly and the motor being wore out that should be good start. Anyway thanks for taking the time to help gentlemen I appreciate it. Let me know on radiator recore. Thanks again guys.

 

[Videris]

Ok got you on TDM. I'll leave that alone. Thanks retiredwarhorses. I appreciate it