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

[GreyZ]

So I recently spent a day doing a bunch of low speed crawling at Barnwell Mountain, and I found that when the AC was off the oil and trans temps would get pretty hot. 225 oil and 210+ for the trans temps. When I kicked the AC on (and forced the fans onto low speed) the temps would come back down to a more reasonable 200/200. While I recognize that the Ford designers probably took all of this into account, I would like to keep things a bit cooler if possible. Especially since this was occuring with outside temps in the low 60s.

Would it be possible to run one of the aux switches to the fan relay turn on wires that would override the Ecu fan signal and force the fans on?

Has anyone else noticed this when crawling for an extended period of time.

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[Bmadda]

So I recently spent a day doing a bunch of low speed crawling at Barnwell Mountain, and I found that when the AC was off the oil and trans temps would get pretty hot. 225 oil and 210+ for the trans temps. When I kicked the AC on (and forced the fans onto low speed) the temps would come back down to a more reasonable 200/200. While I recognize that the Ford designers probably took all of this into account, I would like to keep things a bit cooler if possible. Especially since this was occuring with outside temps in the low 60s.

Would it be possible to run one of the aux switches to the fan relay turn on wires that would override the Ecu fan signal and force the fans on?

Has anyone else noticed this when crawling for an extended period of time.

After looking at the diagrams it appears it's not that simple. The relays are energized any time it's in run, and the speed is pcm controlled.

 

[MsPickles]

Not sure which engine you have, but with the 2.7, there is no cooler directly in the fan path. Both the transmission and oil have heat exchangers tied into the engine cooling system. Those also have valves, controlling the flow of cooling in those heat exchangers, I assume based upon the temperature readings the vehicle is at at that time. So even if you some how wired up a fan to bypass the fan control and turn on, I wouldn't think that would do much good, as the valves that control the heat exchangers are still controlled through the vehicle. Maybe they have some programming that allow the heat exchanger valves to open farther/longer upon the air conditioning running/fans enabled. Seems like one would need the actual program to understand the "why" the trans and oil temps run cooler with the AC on, at your present temperatures.
I wish myself that there were less electronics involved, but kind of stuck with them, for the moment. I could only see one re-routing trans lines or oil lines to an aftermarket cooler so it is independent then. I wonder if it'd throw codes if one did re-rout those lines, but left the "electronics" there so the vehicle would think it's working a normal, but you have full control then with the aftermarket cooler and temperatures?

 

[GreyZ]

After looking at the diagrams it appears it's not that simple. The relays are energized any time it's in run, and the speed is pcm controlled.

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??

 

[swooshdave]

So I recently spent a day doing a bunch of low speed crawling at Barnwell Mountain, and I found that when the AC was off the oil and trans temps would get pretty hot. 225 oil and 210+ for the trans temps. When I kicked the AC on (and forced the fans onto low speed) the temps would come back down to a more reasonable 200/200. While I recognize that the Ford designers probably took all of this into account, I would like to keep things a bit cooler if possible. Especially since this was occuring with outside temps in the low 60s.

Would it be possible to run one of the aux switches to the fan relay turn on wires that would override the Ecu fan signal and force the fans on?

Has anyone else noticed this when crawling for an extended period of time.

Those temps don't look alarming. Chances of you messing something up worse with rewiring is higher.

 

[GreyZ]

Not sure which engine you have, but with the 2.7, there is no cooler directly in the fan path. Both the transmission and oil have heat exchangers tied into the engine cooling system. Those also have valves, controlling the flow of cooling in those heat exchangers, I assume based upon the temperature readings the vehicle is at at that time. So even if you some how wired up a fan to bypass the fan control and turn on, I wouldn't think that would do much good, as the valves that control the heat exchangers are still controlled through the vehicle. Maybe they have some programming that allow the heat exchanger valves to open farther/longer upon the air conditioning running/fans enabled. Seems like one would need the actual program to understand the "why" the trans and oil temps run cooler with the AC on, at your present temperatures.
I wish myself that there were less electronics involved, but kind of stuck with them, for the moment. I could only see one re-routing trans lines or oil lines to an aftermarket cooler so it is independent then. I wonder if it'd throw codes if one did re-rout those lines, but left the "electronics" there so the vehicle would think it's working a normal, but you have full control then with the aftermarket cooler and temperatures?

Well that is worse news. Definitly complicates things a bit. It *seems* that the fans may be coolant based instead of oil/trans temp based. This would explain why turning on the fans with ac would also cool the oil/trans. Is there a good diagram showing these coolant and oil/trans fluid loops so I can better understand what is happening?

 

[DefNotBuddyLee]

Your oil temp seems about normal when wheeling, but the tranny temp seems a little high (but not enough to worry). Depends on how high over 210 you mean with 210+. I run 200-205 easy and still in the green.

You might be able to have an affect on the oil temp based on the oil you are using. I run hotter using Pennzoil Platinum as opposed to Mobil 1 or a euro blend (I'll run about 10 degrees cooler with M1 or some others, but get better MPG from PP). My understanding that Pennzoil Plat is on the thinner side of a 5w30 oil as opposed to these other options (but is still good oil). We can go down a rabbit hole of what is the best oil, but just some info based on my experience.

Transmission solution may be a transmission cooler down the road.

 

[GreyZ]

Those temps don't look alarming. Chances of you messing something up worse with rewiring is higher.

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?

 

[GreyZ]

Your oil temp seems about normal when wheeling, but the tranny temp seems a little high (but not enough to worry). Depends on how high over 210 you mean with 210+. I run 200-205 easy and still in the green.

You might be able to have an affect on the oil temp based on the oil you are using. I run hotter using Pennzoil Platinum as opposed to Mobil 1 or a euro blend (I'll run about 10 degrees cooler with M1 or some others, but get better MPG from PP). My understanding that Pennzoil Plat is on the thinner side of a 5w30 oil as opposed to these other options (but is still good oil). We can go down a rabbit hole of what is the best oil, but just some info based on my experience.

Transmission solution may be a transmission cooler down the road.

210-211. Might have seen 212 once with the ac off. Once the ac was on it never got close to that.

I have been through the endless oil discussions with my Z and it is truly endless, it currently gets M1 euro 0-40 but i would rather not go down that rabbithole with the Bronco. With the Bronco I plan to just run the recommended Motorcraft SynBlend on 5k intervals. Thats what I run in the 3.5EB F150 and it has 215k+ trouble free miles.

 

[swooshdave]

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?

People have had Broncos in way worse heat and I don't recall a lot of complaining.

 

[flip]

Put the Raptor aux trans cooler OTA on and let it eat. I would advise not trying to tap into the cooling fans or altering the strategy.

 

[flip]

 

[BlueBronco]

With the Bronco I plan to just run the recommended Motorcraft SynBlend on 5k intervals. Thats what I run in the 3.5EB F150 and it has 215k+ trouble free miles.

Same, but only 150k on my 3.5EB, so far.
Also, I would recommend similar Kendall or Phillips66 products to be used in a pinch if your local store is out of the MC.

 

[CatMonkey]

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.

 

[DefNotBuddyLee]

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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