Can I use a Aux switch to trigger the fans. Bronco Oil Temp gets HOT in 4 lo.

[Bmadda]

Thank you for finding that. I tried and could not find a diagram of the fans. I am not surprised that it is PCM controlled outside of the relay.

Or determine if the VE203 wire is an analog voltage signal from the PCM or a CanBus data signal to the fan controller.

If its through the PCM would it be possible to adjust the speeds and turn on temps in forscan??

From description/operation-cooling:

" The PCM controls the fan speed and operation using a duty cycle output on the FCV circuit. The fan controller (located at or integral to the engine cooling fan assembly) receives the FCV command and operates the cooling fan at the speed requested (by varying the power applied to the fan motor). "

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[AZ_Liberty]

My 94 XJ ran so hot I ended up wiring the fan directly by bypassing the relay. I also removed the thermostat, and replaced the radiator with an oversize one.

Still ran hot, especially if driving west, but it helped.

With everything computer controled these days, I don't know how much luck you will have. If it's PWM as indicated above, you might have to build a little PWM module, though I'd be willing to try straight 12V.

 

[SS Bronco]

I agree, I think my concern is more that I was seeing these temps at 50/60 ambient temps and I am worried when it is 110 outside. 220 isnt necessarily alarming, but with the motorcraft syn blend, I really would rather not push it to the 240s+ if it was avoidable.

Has anyone else seen these high oil temps when wheeling in moab or somewhere very hot?

For me thats is the max temperature no matter what the outside temperature is. Running for hours in the sands of Baja or wheeling the Rubicon for 10 hours, it so far stays the same max but drops back quickly to the low 200’s.

 

[GreyZ]

I don't really think those temps are high enough to be concerned with. But have you given any consideration to to a lower thermostat? I'm not sure what the stock thermostat is rated at, but Ford generally uses stats between 192° and 198°, and set their fans to have the engine run in the 205°, give or take, range, all for the sake of CAFE. I see SPD makes a 170° and a 180° thermostat, and I'm sure there are others available too.

I do not want a cooler thermostat. Not good for daily driving to keep it that cool.

I have run in Texas summer heat (100+) and get similar temps to what you saw, so I would not worry yet. I got similar oil/trans temps when running in the cooler weather of Moab so that may just be severe duty operating temp.
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That is good to know.

For me thats is the max temperature no matter what the outside temperature is. Running for hours in the sands of Baja or wheeling the Rubicon for 10 hours, it so far stays the same max but drops back quickly to the low 200’s.

That is reassuring. It sounds like I am just overthinking it a bit. I do not want to make any changes to the Bronco's control logic. If simply running a second turn on for the fan relay was a possibility, I think I may have done that. More than that and I am not interested in altering it. I am doing the texas off roadeo next month, so I will make sure to watch what those get up to in the crawling. If it continues to be a problem I will look into adding the Raptor trans cooler that @flip linked in his post.


It seems like Ford could have lowered the fan turn on temp in the Rock Crawl Goat Mode to alleviate much of this concern, but I am nearly certain the fan turn on speed is not altered with GOAT modes.

 

[CatMonkey]

I do not want a cooler thermostat. Not good for daily driving to keep it that cool.

Thermostats are rated at where they begin to open. They don't completely open until several degrees above that. Unless you're driving in 20° temperatures, you'll not likely to see the cooling system maintain the thermostat rating. But to each his own.

 

[swami37]

Why not just leave a/c on so the fans will come on?

 

[GreyZ]

Why not just leave a/c on so the fans will come on?

It was in the 50s outside and we did not need it. We later realized that keeping AC on dropped the oil and trans temps ~20 degrees because it caused the fans to kick on so that is what we did. Sometimes it seems silly to have the ac blowing when its cold and the doors and top are all off.

 

[MotoVexGT]

I wonder if the performance tune alters when the fans come on. I know that when we tune my bikes, we alter the ECU programming to turn the fans on at a lower temp. Motorcycles are vastly less complex, but it would be interesting to see if the Ford tune was altered to do that, or if that feature is unlocked for FORScan or something to change.

 

[GreyZ]

I wonder if the performance tune alters when the fans come on. I know that when we tune my bikes, we alter the ECU programming to turn the fans on at a lower temp. Motorcycles are vastly less complex, but it would be interesting to see if the Ford tune was altered to do that, or if that feature is unlocked for FORScan or something to change.

My Z has the ecu tuning to turn the fans on earlier to help with the heat soak from the turbo. That is a good point about the performance tune. Maybe @LethalPerformance @lethaljake or @Mitch Panda Motorworks

 

[Greasyfingers429]

FWIW, My transmission temps once peaked up to 242 degrees — and you could smell it — driving in loose dune sand last summer. It was probably 80 degrees outside. That was alarming for me, but I rarely run it that hard. In fact, I found that crawling at a lower speed and letting the transmission choose a gear was better than me trying to manually shift. This was in 4H; GOAT mode = sand.
If there was a way to lower those temps with a MOD fan ECU program or a switch, I would consider it, too.

 

[B22-2023]

In the 2023 WT the other day I was grinding up some deep muddy tracks in CO, ambient temp 45 degrees and dry. Engine oil temp went up to 245 degrees, they say 260 is top/redline. Brand new oil from Ford Performance in Moab the day before. Moab oil temps while crawling there were routinely 225-230.

I also wonder what that engine oil temp would have been in the TX summer with higher ambient temps. I think I’m going to add this passive cooler or something similar, as done on my previous Early Broncos. Seems like a cheap way to be safe, though let’s see if it throws codes or has a knock-on effect on the stock cooling gear.

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