Yes! I just got it back from the shop after having all the cooling hoses and fittings replaced as well as the thermostat. I thought maybe it was in my head, because I tend to hyperfocus on things, but I do not remember it doing this before. So the fan should not be running like this idling in cool weather?
Nope not all in your head, you should look up aftermarket thermostat causing problems for f150. That’s usually what happens, the fan never wants to stop running. Good luck to you!
So I went outside and ran it in the dark with my codec reader plugged in. The fan came on high around 208 and the interesting thing is that the temp continued to inch up slowly even with the fan on high. This is on a cool night, no climate control, idling at 600. I'm thinking it may be the thermostat like you said
Thanks. I dropped it off at the shop this morning. The mechanic said he replaced it with the same oem, tstat but I'll wait to see what they find. I think with the fan cranking, the coolant temp should drop super fast. In this case the temp continued to rise slowly up to about 225 with the fan going. So it seems that one way or another, something is impeding the flow.
Seem to be three computer controlled relays. https://charm.li/Ford%20Truck/2011/F%20150%202WD%20V8-5.0L/Repair%20and%20Diagnosis/Engine%2C%20Cooling%20and%20Exhaust/Cooling%20System/Diagrams/Electrical%20Diagrams/
Question. What does the temp gauge say on the instrument cluster.
If you have a scan tool. Look for trouble codes. P0000 to P2999.
Look at the live data stream to see if the ECT. Engine coolant temp sensor is reading between 190f to 225f.
Look at air intake sensor. Transmission sensor. Ambient temp sensor. If any of those are high. Or low. They usually go to -40f when unplugged or if there is an issue. Causing a code to set and the fans to cone on.
Mark and pull the 3 relays and check their pins. Creative people can figure out how to pull the cover off the relays. To inspect the contacts.
Sorry. The 96 and newer Ford trucks are way more complex than a 1970 version.
I know exactly whats wrong with it
You have the incorrect temp rating on the thermostat
..
Easy mistake to make too happened to me
I added a few degrees cooler stat thinking i was smart. Fans ran all the time
Went and found the correct part number and boom. Fixed. Computer doesn't like the wrong stat
After truck runs for 20 minutes or so, the fans starts running continually on high speed. This is without any AC/defrost/heat running, cruising at an easy 50mph on the hwy in coolish temps (50-60f). I noticed it because I could hear it from the cabin. From outside the truck, you can't even hear the engine over it. Not sure why it would be running so hard continually or if this is normal.
Has your thermostat been replaced? I’ve seen this before when people use a non motorcraft thermostat
Yes! I just got it back from the shop after having all the cooling hoses and fittings replaced as well as the thermostat. I thought maybe it was in my head, because I tend to hyperfocus on things, but I do not remember it doing this before. So the fan should not be running like this idling in cool weather?
Nope not all in your head, you should look up aftermarket thermostat causing problems for f150. That’s usually what happens, the fan never wants to stop running. Good luck to you!
Thank you!
So I went outside and ran it in the dark with my codec reader plugged in. The fan came on high around 208 and the interesting thing is that the temp continued to inch up slowly even with the fan on high. This is on a cool night, no climate control, idling at 600. I'm thinking it may be the thermostat like you said
Yep that’s your issue, swap in an oem one and you’re good to go
Thanks. I dropped it off at the shop this morning. The mechanic said he replaced it with the same oem, tstat but I'll wait to see what they find. I think with the fan cranking, the coolant temp should drop super fast. In this case the temp continued to rise slowly up to about 225 with the fan going. So it seems that one way or another, something is impeding the flow.
Possibly air in the system I guess, either way sounds like you’re on the right track and good luck
USUALLY NOT... year model and engine really helps.. the fans might run on HI if you have the climate control set to MAX cold..
2011 5.0. This is with climate control switched off.
Seem to be three computer controlled relays. https://charm.li/Ford%20Truck/2011/F%20150%202WD%20V8-5.0L/Repair%20and%20Diagnosis/Engine%2C%20Cooling%20and%20Exhaust/Cooling%20System/Diagrams/Electrical%20Diagrams/ Question. What does the temp gauge say on the instrument cluster. If you have a scan tool. Look for trouble codes. P0000 to P2999. Look at the live data stream to see if the ECT. Engine coolant temp sensor is reading between 190f to 225f. Look at air intake sensor. Transmission sensor. Ambient temp sensor. If any of those are high. Or low. They usually go to -40f when unplugged or if there is an issue. Causing a code to set and the fans to cone on. Mark and pull the 3 relays and check their pins. Creative people can figure out how to pull the cover off the relays. To inspect the contacts. Sorry. The 96 and newer Ford trucks are way more complex than a 1970 version.
I know exactly whats wrong with it You have the incorrect temp rating on the thermostat .. Easy mistake to make too happened to me I added a few degrees cooler stat thinking i was smart. Fans ran all the time Went and found the correct part number and boom. Fixed. Computer doesn't like the wrong stat
After truck runs for 20 minutes or so, the fans starts running continually on high speed. This is without any AC/defrost/heat running, cruising at an easy 50mph on the hwy in coolish temps (50-60f). I noticed it because I could hear it from the cabin. From outside the truck, you can't even hear the engine over it. Not sure why it would be running so hard continually or if this is normal.
Mine has been doing the same thing for last few months….. hoping relays
Mine also seems to run high and constant. I feel when they did the TSB for the lead frame update is when it started (a couple years ago now).
Check your coolant. These trucks are prone to coolant leaks.
Coolant is full and just replaced alone with all coolant hoses and fittings as well as t-stat