Radiator Fan Conundrum

[apex96]

New issues with my 2018 Expedition. After all the modifications and updates I installed I was finally satisfied with it. Heck even the clunking noise went away (still not sure how or why) and I thought I had my perfect SUV sorted… I was wrong.

Recently on a trip to Richmond VA to visit a friend I heard a pop in the engine bay (or so it sounded like it) that unnerved me. I kept a close eye on my gauges and noticed the engine temp was running warmer than normal. I have a 170 degree thermostat installed so warmer means it’s creeping up on 180+ and not coming down fast.

I monitored temps during the drive to and then back from Richmond to the Pittsburgh PA area, through the mountains. Temps crested over 205 briefly once. This is not normal for my setup. Dropped it off at an independent dealer as ford won’t touch it since I’ve modified the cooling system.

It’s been with my preferred independent shop for three weeks. They found at least two issues currently. First thing they found was that neither the low or high speed radiator fans were running. They changed the high speed radiator fan relay and got them operating. They come on around 217 degrees Fahrenheit. The real issues is the low speed fan… the low speed fan will not come on at all, on its own. The shop can command it on through a scan tool or by max defrost on the climate setting. The fan fails to come on, on its own. Temps at idle will climb until 217 when the high speed kicks on.

Shop cannot figure out what temp the low speed is supposed to be commanded on at. They’ve researched and even have feelers out with a former ford engineer. They’re hesitant to go further until they have a confirmed temp that the low speed fan is supposed to be commanded on at.

I’ve authorized them to swap the aftermarket 170 thermostat with a factory 185 degree (plastic end piece) and complete the switch from orange to yellow coolant while they have it.

For reference the shop said 2019 f150 2.7 ecoboost low speed fan is commanded on around 165 degrees Fahrenheit. While different engines the temp seems reasonable for activation of the low speed fans.

My expedition has the two wire radiator fan as I do not have the HD tow package. Any help from the community is appreciated. I really would love to get this sorted and hopefully/finally enjoy some trouble free years out of her (who am I kidding… she loves sitting in shops!)

Thanks!

 

[VCFP153]

Since I am not sure what other modifications you made to the cooling system, I am not able to give you any pointers beyond suggesting that, if you are that concerned with the low-speed fan, why not just rig up a separate switch and a relay for it, so you can activate it manually whenever you like?

 

[bmpcamry09]

If your tuned for the 170 thermostat, your activation temperature for the fan is going to be different than whatever Ford tells them.

In my tuning, and I know a few other companies tunes as well, fans on a 170 thermostat setup are usually starting to come on around 185. Factory stock, the fans are commanded to low at 202.

Here’s some pics of the stock tables from an Expedition. Then pics show the differences in how a 170 thermostat tune is generally setup. If your tuner did it properly that is. This should help you and your shop.

 

[apex96]

If your tuned for the 170 thermostat, your activation temperature for the fan is going to be different than whatever Ford tells them.

In my tuning, and I know a few other companies tunes as well, fans on a 170 thermostat setup are usually starting to come on around 185. Factory stock, the fans are commanded to low at 202.

Here’s some pics of the stock tables from an Expedition. Then pics show the differences in how a 170 thermostat tune is generally setup. If your tuner did it properly that is. This should help you and your shop.

Thanks this is good to know.
I do have the tune file from Adam with ZFG. I haven’t reinstalled it since early this spring when I had a torque converter replaced under an extended transmission replacement warranty. I talk with the shop Monday as it sounds like there are definitely issues with the system beyond the fans if the coolant temp is rising above the thermostat open point.

With the factory file it never got as hot as it did after I heard the pop and it would always stay cool in traffic, rarely going over 185 and quickly recover to between 165-170, so something has happened, will just have to continue to troubleshoot.

I am replacing the 170 with the newer factory thermostat with the plastic base as I was never truly happy with the 170s metal base and how it felt. It worked but didn’t feel smooth when cycled in hand.

 

[apex96]

Since I am not sure what other modifications you made to the cooling system, I am not able to give you any pointers beyond suggesting that, if you are that concerned with the low-speed fan, why not just rig up a separate switch and a relay for it, so you can activate it manually whenever you like?

As of now, just the thermostat has been swapped out. It’s running the stock tune currently. I do have a tune from ZFG that I’ve run before that’s tuned for the 170 thermostat. Tune was taken out earlier this year when I had a torque converter replaced under warranty.

 

[apex96]

Wanted to close the loop on this issue. Shop replaced the relay and the fans began to work. As described above in my previous posts, the fans were coming on around 210 degrees... This was the factory set point for them turning on... ZFG had not lowered the set point for the fans to work with the colder thermostat on their tune. Swapped to the 185 degree thermostat and began working with bpcamry09 on a new tune. Right now the new tunes I've been working with bp on have set the fans to come on around 195 which is much better than the factory setting of 210.

I still cannot fathom why Ford wants to run everything so dang hot. GM keeps the engine coolant around 175/180 and the trans temps around 145/150 for their drive trains and honestly Ford should too. Heat kills and these hotter temps will likely shorten overall engine life.

 

[Jaber 1217]

فوFord Expedition 2019 A problem with the radiator fans does not work at all, and the code p0481 is set, knowing that the fans, PCM, fuse wire set, and fuse box have been changed, please help

 

[UstonXpedition]

Do you know which fan relay it is or part number? Would this be a part I can pick up at any local parts store. Asking cause im on vacation and started noticing the highspeed fan not turning on. low speed will turn on with ac and when temps is at 212. but not high.

 

[Rednecked]

I’ve learned with swapping out thermostats. Keep it stock and drive. Be happy…

 

[Dice Roll]

Wanted to close the loop on this issue. Shop replaced the relay and the fans began to work. As described above in my previous posts, the fans were coming on around 210 degrees... This was the factory set point for them turning on... ZFG had not lowered the set point for the fans to work with the colder thermostat on their tune. Swapped to the 185 degree thermostat and began working with bpcamry09 on a new tune. Right now the new tunes I've been working with bp on have set the fans to come on around 195 which is much better than the factory setting of 210.

I still cannot fathom why Ford wants to run everything so dang hot. GM keeps the engine coolant around 175/180 and the trans temps around 145/150 for their drive trains and honestly Ford should too. Heat kills and these hotter temps will likely shorten overall engine life.

GM uses bigger engines with multi displacement and that might solve emissions for them. It also causes all sorts of issues and somebody in my family has a truck that needs all sorts of money thrown at it or simply replaced with a new truck because of that. Ford thankfully uses the small engine and supplements with the turbos for power. I could see higher temps being part of their strategy since we are strangled by multi displacement bs.

After the new stat went in, my trans runs 180-192 most of the time. Still a little over 200 when towing. Better than before the new stat when it was 215 towing and 205 in regular driving. I don’t see an issue with those temps now.

 

[apex96]

Do you know which fan relay it is or part number? Would this be a part I can pick up at any local parts store. Asking cause im on vacation and started noticing the highspeed fan not turning on. low speed will turn on with ac and when temps is at 212. but not high.

I don’t have the relay information on hand. I did learn that the non HD tow package expedition doesn’t have a high and low speed fan, it’s a variable speed fan and it will ramp up and ramp down as needed. Since your fans are coming on when it hits 212 that tells me that they’re working as designed… I didn’t like that high of a command on temp and had a custom tune made to set a lower activation temperature.

I would find a good tuner to work with and have them create a tune that incorporates a lower fan activation temperature.

 

[scsulliv]

If you are talking about a standard brushed fan, then the following wiring diagram explains how the setup works. Basically, 3 different relays are used to enable low speed fans, high speed fans, or disable them altogether. The relays work to create either a series or a parallel circuit between the 2 fan motors. The loud popping noise that the original poster heard was probably a relay failing.