5.0 cylinder head temperature sensor location (engine coolant temp sensor)
12-22-2018, 03:20 AM
#1
Senior Member
Thread Starter
5.0 cylinder head temperature sensor location (engine coolant temp sensor)
2016 5.0 w/ supercharger. Belts ok, fans running, coolant level correct and unchanged.
I'm posting this in this forum as there seems to be more DIY types active here than anywhere else.
Tonight, while going to work, my cluster flashed an engine coolant over-temperature warning despite my SCT gauge showing coolant temperatures under 200 degrees, and not long after when exiting the highway onto a frontage road, I lost all power and my truck seemed to go into limp home mode. It would barely move, so I pulled off into a nearby parking lot and walked the rest of the way to work. Had it towed to the house while at work, and when I get off I'm gonna be checking the wiring going to the coolant temp sensor...but one problem, I don't know where it is lol.
Is the the temp sensor still on the passenger side cylinder head near the firewall? I'm hoping I can get access to it, as I'm suspecting a faulty sensor as there is no obvious mechanical reason for the overheat, and there were no funny smells and the engine was not overly hot to the touch. When I get off work, I'm gonna pull any codes and reset them to see if I can get it to start normally. After I shut it down when I pulled into the parking lot, it was very hard to restart and once started continued to flash the overheat warning and drove like ****. There is simply no way my truck overheated unless the water pump impeller broke off or disintegrated, as everything else is still intact.
I'm posting this in this forum as there seems to be more DIY types active here than anywhere else.
Tonight, while going to work, my cluster flashed an engine coolant over-temperature warning despite my SCT gauge showing coolant temperatures under 200 degrees, and not long after when exiting the highway onto a frontage road, I lost all power and my truck seemed to go into limp home mode. It would barely move, so I pulled off into a nearby parking lot and walked the rest of the way to work. Had it towed to the house while at work, and when I get off I'm gonna be checking the wiring going to the coolant temp sensor...but one problem, I don't know where it is lol.
Is the the temp sensor still on the passenger side cylinder head near the firewall? I'm hoping I can get access to it, as I'm suspecting a faulty sensor as there is no obvious mechanical reason for the overheat, and there were no funny smells and the engine was not overly hot to the touch. When I get off work, I'm gonna pull any codes and reset them to see if I can get it to start normally. After I shut it down when I pulled into the parking lot, it was very hard to restart and once started continued to flash the overheat warning and drove like ****. There is simply no way my truck overheated unless the water pump impeller broke off or disintegrated, as everything else is still intact.
12-22-2018, 05:01 AM
#2
Senior Member
Thread Starter
I think I found a diagram, it is indeed on the passenger side cylinder head, near the base of the intake manifold. Hopefully I can get to it, though at the very least I should be able to get my borescope back there to take a look.
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rotorbudd (07-25-2019)
12-22-2018, 08:59 AM
#3
Senior Member
Thread Starter
Finally got home, that was an expensive Uber. Cleared three codes, P0219 (engine overspeed), P1285 (over temp), and P1289 (CHT sensor voltage out of range). The car had been sitting overnight in 40 degree temperatures, but when turning on the ignition, it still said it was overheating. I cleared the codes and it started right up, and I drove it around for a few minutes without any issues. Using my SCT gauge I was watching the water temps slowly climb, and right around 160 degrees, when I was making the turn to go back to my house (thankfully), it threw the overheat warning and died (code P1289). I also noticed just before the over heat warning, the engine coolant temperature display on my SCT was showing -47 degrees. I cleared the code on the side of the road, got it started and limped it home, where it promptly kicked the bucket again in my garage (throwing code P1289), this time being difficult to restart. I disconnected the battery, waited a few minutes, got it to start and pulled it the rest of the way in my driveway when it again threw the same code, P1289
While it was in my garage, I put my hand on the cylinder head and it was warm to the touch, barely 140 degrees if I had to guess. This is not an overheat issue, but an electrical one. Ford's strategy goes into limp home mode above 250 degrees, where it disables 4 cylinders (tuns off fuel injectors), however above 310 degrees it shuts off all fuel injectors. I'm thinking the CHT sensor is indicating something over 310 degrees, which is causing the truck to die. So I'll be ordering a new sensor and inspecting the wiring as best I can. Its gonna be a bitch to get to, but I should be able to access the CHT blind, if I literally crawl into the engine bay. But that's gonna have to wait till next week, catching a flight out of state for the holidays.
While it was in my garage, I put my hand on the cylinder head and it was warm to the touch, barely 140 degrees if I had to guess. This is not an overheat issue, but an electrical one. Ford's strategy goes into limp home mode above 250 degrees, where it disables 4 cylinders (tuns off fuel injectors), however above 310 degrees it shuts off all fuel injectors. I'm thinking the CHT sensor is indicating something over 310 degrees, which is causing the truck to die. So I'll be ordering a new sensor and inspecting the wiring as best I can. Its gonna be a bitch to get to, but I should be able to access the CHT blind, if I literally crawl into the engine bay. But that's gonna have to wait till next week, catching a flight out of state for the holidays.
12-22-2018, 05:50 PM
#4
Sounds like a wire got chewed, shorted or pinched imo.
12-22-2018, 06:15 PM
#5
Originally Posted by BadCon
Finally got home, that was an expensive Uber. Cleared three codes, P0219 (engine overspeed), P1285 (over temp), and P1289 (CHT sensor voltage out of range). The car had been sitting overnight in 40 degree temperatures, but when turning on the ignition, it still said it was overheating. I cleared the codes and it started right up, and I drove it around for a few minutes without any issues. Using my SCT gauge I was watching the water temps slowly climb, and right around 160 degrees, when I was making the turn to go back to my house (thankfully), it threw the overheat warning and died (code P1289). I also noticed just before the over heat warning, the engine coolant temperature display on my SCT was showing -47 degrees. I cleared the code on the side of the road, got it started and limped it home, where it promptly kicked the bucket again in my garage (throwing code P1289), this time being difficult to restart. I disconnected the battery, waited a few minutes, got it to start and pulled it the rest of the way in my driveway when it again threw the same code, P1289
While it was in my garage, I put my hand on the cylinder head and it was warm to the touch, barely 140 degrees if I had to guess. This is not an overheat issue, but an electrical one. Ford's strategy goes into limp home mode above 250 degrees, where it disables 4 cylinders (tuns off fuel injectors), however above 310 degrees it shuts off all fuel injectors. I'm thinking the CHT sensor is indicating something over 310 degrees, which is causing the truck to die. So I'll be ordering a new sensor and inspecting the wiring as best I can. Its gonna be a bitch to get to, but I should be able to access the CHT blind, if I literally crawl into the engine bay. But that's gonna have to wait till next week, catching a flight out of state for the holidays.
While it was in my garage, I put my hand on the cylinder head and it was warm to the touch, barely 140 degrees if I had to guess. This is not an overheat issue, but an electrical one. Ford's strategy goes into limp home mode above 250 degrees, where it disables 4 cylinders (tuns off fuel injectors), however above 310 degrees it shuts off all fuel injectors. I'm thinking the CHT sensor is indicating something over 310 degrees, which is causing the truck to die. So I'll be ordering a new sensor and inspecting the wiring as best I can. Its gonna be a bitch to get to, but I should be able to access the CHT blind, if I literally crawl into the engine bay. But that's gonna have to wait till next week, catching a flight out of state for the holidays.
12-30-2018, 09:54 PM
#6
Senior Member
Thread Starter
Finally got back in state from the holidays and the first order of business was to get my truck running. It was a pain in the ***, but I got the new sensor installed. I had to lay across the engine bay to do it, and I used my borescope as my eyes, as its tucked way down at the back of the motor on the passenger side, and there is no way to get a visual on it with the engine in the vehicle. Thankfully the little brass CHT sensor is just a little more then finger tight, so it was easy to get off and on with a stubby wrench. 19mm deep well socket for anyone who needs to do this in the future. I'd also invest in a pair of flexible grabbers just in case you drop the new CHT sensor under the lower manifold while trying to install it...
Truck is back up and running like a champ, and there was nothing wrong with the wiring, this was all due to a bad sensor. $6 part disabled the whole rig...so annoying.
Truck is back up and running like a champ, and there was nothing wrong with the wiring, this was all due to a bad sensor. $6 part disabled the whole rig...so annoying.
Last edited by BadCon; 12-31-2018 at 12:50 AM.
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rotorbudd (07-25-2019)
12-30-2018, 10:14 PM
#7
TOTM Sept. '18
iTrader: (1)
Glad you got it up and running and nothing serious, and I'll remember this as things that will probably happen to me in the future.
MIke
MIke
Trending Topics
05-26-2019, 11:00 AM
#8
Glad I found this
My truck cold hot gauge keeps fluctuating from normal down to cold. My code reader that has live date shows it drops sometimes to -40 degrees but everything drives normal no codes, I hope it’s just this sensor. When I stop everything goes back to normal, any thoughts?
10-06-2019, 08:01 PM
#9
Senior Member
Finally got back in state from the holidays and the first order of business was to get my truck running. It was a pain in the ***, but I got the new sensor installed. I had to lay across the engine bay to do it, and I used my borescope as my eyes, as its tucked way down at the back of the motor on the passenger side, and there is no way to get a visual on it with the engine in the vehicle. Thankfully the little brass CHT sensor is just a little more then finger tight, so it was easy to get off and on with a stubby wrench. 19mm deep well socket for anyone who needs to do this in the future. I'd also invest in a pair of flexible grabbers just in case you drop the new CHT sensor under the lower manifold while trying to install it...
Truck is back up and running like a champ, and there was nothing wrong with the wiring, this was all due to a bad sensor. $6 part disabled the whole rig...so annoying.
Truck is back up and running like a champ, and there was nothing wrong with the wiring, this was all due to a bad sensor. $6 part disabled the whole rig...so annoying.