Engine coolant over temperature alert on

Tiny
MGALVAN714
  • MEMBER
  • 2014 FORD EXPLORER
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 57,000 MILES
Going to work this morning, my car immediately triggered the alert in the title. Car could not be hot. It was 46° and had been sitting in my driveway all night. Plus it has never overheated. Now my check engine light is on. What could it be?

In addition to previous comments, fan is now continuously running. My temperature gauge does not move. It stays down (indicating cold temperature). After driving around, my engine does not feel or "smell" hot. Coolant level was at appropriate level. Over temperature alert was sudden; no reason for the alert while first turning ignition in the morning.
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Thursday, December 27th, 2018 AT 8:42 PM

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Tiny
JACOBANDNICKOLAS
  • EXPERT
Hi and thanks for using 2CarPros.

First, keep in mind that anything that can have an adverse affect on the vehicle's emissions are still under warranty and you should contact a dealer.

If you want to do it yourself, scan the computer to determine what trouble codes are listed. Based on your description, it sounds like a failed coolant temperature sensor. Here is a quick video showing how that is done:

https://youtu.be/YV3TRZwer8k

Do this and let me know what you find.

Joe
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Thursday, December 27th, 2018 AT 9:34 PM
Tiny
MGALVAN714
  • MEMBER
You are awesome help, Joe! Scan produced a P1289 code. I ordered the coolant temperature sensor, but looking now at the code, the fault states, "P1289 Cylinder Head Temperature Sensor Circulation High Input. Are the coolant temperature sensor and the cylinder head temperature sensor one in the same? From my research so far, I suppose it can be. I've read that the sensor depends on the vehicle system since some vehicles have the sensor on the cylinder head, intake manifold, or near thermostat. Am I understanding this correctly? I appreciate your expertise, Joe. Thank you so much.
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Friday, December 28th, 2018 AT 9:37 PM
Tiny
JACOBANDNICKOLAS
  • EXPERT
Welcome back and you are very welcome. On your vehicle, the sensor is one in the same. The bad part is (and I'm basing this on the 3.5L V6 engine), the sensor is located under the intake manifold and requires removal of the intake to access it. It makes a five minute job take hours.

Before you get started on this, you may want to contact the local Ford Dealership. This vehicle has a 7 year/70,000 mile emissions warranty on many of the parts. Considering a coolant temperature sensor will change the emissions emitted into the atmosphere, it should be covered under the warranty. Also, you don't have to be the first owner for this to apply.

To replace the sensor, you first have to remove the upper and then lower intake manifolds. I will provide the directions in the order you need to do them. They will be in this order:

1) Upper intake removal
2) Lower Intake removal
3) Coolant temp sensor

All attached pictures will correlate with these directions.

____________________________________________________________________

Upper intake, the first 12 pics correlate with this process.

Upper Intake Manifold

Removal
NOTICE: If the engine is repaired or replaced because of upper engine failure, typically including valve or piston damage, check the intake manifold for metal debris. If metal debris is found, install a new intake manifold. Failure to follow these instructions can result in engine damage.

1. Remove the ACL (Air Cleaner) outlet pipe. Refer to Intake Air System Components - Exploded View See: Air Cleaner Housing > Removal and Replacement > Intake Air System Components - Exploded View.

2. Disconnect the EVAP (Evaporative Emission) canister purge valve and throttle body electrical connectors.
- Detach the wiring harness pin-type retainer.

3. Disconnect the EVAP (Evaporative Emission) vapor tube from the EVAP (Evaporative Emission) canister purge valve. REFER to Section 310-00, Quick Connect Coupling See: Fuel Line Coupler > Removal and Replacement > Quick Connect Coupling.
- Detach the EVAP (Evaporative Emission) vapor tube from the 2 retainers.

4. Release the clamps and disconnect the power brake booster vacuum supply hose and crankcase ventilation hose from the upper intake manifold.

5. Detach the 2 coolant tube retainers from the upper intake manifold.

6. Remove the upper intake manifold support bracket bolt.

7. Remove the 7 bolts and the upper intake manifold.
- Remove and discard the gasket.

- Clean and inspect all of the sealing surfaces of the upper and lower intake manifold.

Installation

1. Using a new gasket, install the intake manifold and the 7 bolts and tighten in the sequence shown in 2 stages.
- Stage 1: Tighten to 10 Nm (89 lb-in).

- Stage 2: Tighten an additional 45 degrees.

2. Install the upper intake manifold support bolt.
- Tighten to 10 Nm (89 lb-in).

3. Attach the 2 coolant tube retainers to the upper intake manifold.

4. Connect the power brake booster vacuum supply hose and crankcase ventilation hose to the upper intake manifold.

5. Connect the EVAP (Evaporative Emission) vapor tube to the EVAP (Evaporative Emission) canister purge valve. REFER to Section 310-00, Quick Connect Coupling See: Fuel Line Coupler > Removal and Replacement > Quick Connect Coupling.
- Attach the EVAP (Evaporative Emission) vapor tube to the 2 retainers.

6. Connect the EVAP (Evaporative Emission) canister purge valve and throttle body electrical connectors.
- Attach the wiring harness pin-type retainer to the upper intake manifold.

7. Install the ACL (Air Cleaner) outlet pipe. Refer to Intake Air System Components - Exploded View See: Air Cleaner Housing > Removal and Replacement > Intake Air System Components - Exploded View.

____________________

Lower Intake Manifold Start at picture 13

LOWER INTAKE MANIFOLD

Lower Intake Manifold

Removal
NOTICE: During engine repair procedures, cleanliness is extremely important. Any foreign material, including any material created while cleaning gasket surfaces that enters the oil passages, coolant passages or the oil pan, can cause engine failure.

1. With the vehicle in NEUTRAL, position it on a hoist. REFER to Section 100-02, Jacking and Lifting See: Vehicle Lifting > Procedures > Jacking and Lifting, Lifting Points.

2. Release the fuel system pressure. REFER to Section 310-00, Fuel System Pressure Release See: Fuel Pressure Release > Procedures > Fuel System Pressure Release.

3. Disconnect the battery ground cable. Refer to Battery Disconnect See: Battery > Removal and Replacement > Battery Disconnect.

4. Drain the cooling system. Refer to Cooling System Draining, Filling and Bleeding See: Cooling System > Procedures > Cooling System Draining, Filling and Bleeding.

5. Remove the upper intake manifold. Refer to Upper Intake Manifold See: Intake Manifold > Removal and Replacement > Upper Intake Manifold.

6. Disconnect the 6 fuel injector electrical connectors.

7. Disconnect the fuel supply tube-to-fuel rail quick connect coupling. REFER to Section 310-00, Quick Connect Coupling See: Fuel Line Coupler > Removal and Replacement > Quick Connect Coupling. Position fuel supply tube aside.
- Remove the bolt from the fuel supply tube-to-rail bracket.

8. Remove the 2 thermostat housing-to-lower intake manifold bolts.

9. Remove the 10 bolts and the lower intake manifold.
- Remove and discard the intake manifold and thermostat housing gaskets.

- Clean and inspect all sealing surfaces.

Installation

1. NOTICE: If the engine is repaired or replaced because of upper engine failure, typically including valve or piston damage, check the intake manifold for metal debris. If metal debris is found, install a new intake manifold. Failure to follow these instructions can result in engine damage.

Using new intake manifold and thermostat housing gaskets, install the lower intake manifold and the 10 bolts.

- Tighten in the sequence shown to 10 Nm (89 lb-in).

2. Install the 2 thermostat housing-to-lower intake manifold bolts.
- Tighten to 10 Nm (89 lb-in).

3. Connect the fuel supply tube-to-fuel rail quick connect coupling. REFER to Section 310-00, Quick Connect Coupling See: Fuel Line Coupler > Removal and Replacement > Quick Connect Coupling.
- Install the bolt to the fuel supply tube-to-rail bracket and tighten to 10 Nm (89 lb-in).

4. Connect the 6 fuel injector electrical connectors.

5. Install the upper intake manifold. Refer to Upper Intake Manifold See: Intake Manifold > Removal and Replacement > Upper Intake Manifold.

6. Connect the battery ground cable. Refer to Battery Disconnect See: Battery > Removal and Replacement > Battery Disconnect.

7. Fill and bleed the cooling system. Refer to Cooling System Draining, Filling and Bleeding See: Cooling System > Procedures > Cooling System Draining, Filling and Bleeding.

_____________________________

Finally, here are the directions for replacing the sensor. The last two pictures correlate with these directions.

____________________________

Cylinder Head Temperature (CHT) Sensor - 3.5L Ti-VCT, 3.7L Ti-VCT

Exploded View

Removal
WARNING: Before beginning any service procedure, refer to Safety Warnings. Failure to follow this instruction may result in serious personal injury.

1. Remove the lower intake manifold. For 3.5L Twin Independent Variable Cam Timing (Ti-VCT) engine, See: Intake Manifold > Removal and Replacement > Lower Intake Manifold.

2. Disconnect the CHT (Cylinder Head Temperature) sensor electrical connector.

3. Remove and discard the CHT (Cylinder Head Temperature) sensor.
Installation

1. NOTE: Do not reuse the CHT (Cylinder Head Temperature) sensor. Install a new sensor.

Install a new CHT (Cylinder Head Temperature) sensor.

- Tighten to 10 Nm (89 lb-in).

2. Connect the CHT (Cylinder Head Temperature) sensor electrical connector.

3. Install the lower intake manifold. For 3.5L Twin Independent Variable Cam Timing (Ti-VCT) engine, See: Intake Manifold > Removal and Replacement > Lower Intake Manifold.

___________________

As you can see, it's a big job. Please feel free to let me know if you have questions or need help with anything.

Take care,
Joe
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Friday, December 28th, 2018 AT 10:19 PM
Tiny
MGALVAN714
  • MEMBER
Thanks again for the detailed information, Joe. I was hesitating because I had a big job ahead of me. The dealer told me temperature sensor was not covered under emissions warranty. I informed rep that my car was producing code P1289. He was awesome enough to inform me that to change out sensor would a ballpark cost of about $600.00. After taking a look at the engine, it still looked like a big job, but as cumbersome as I initially imagined. I started off by removing the rubber engine cover. I immediately noticed shredded pieces of paper (like another member reported being the work of rats) and thought of frayed cables. As I searched for the temperature sensor, I noticed there was a wire broken off, with the second cable showing a bit of wire. I figured I should start off fixing that before starting with the replacement of the temperature sensor. I ended up removing the connector by cutting off the second wire, and repairing wires. It was a bit of a tedious job because I had to remove the pins from the connector. For a moment, a piece broke off so I thought I had finished breaking it, but I was able to repair the broken wires, reinstall it, and then start the engine. No more Engine Coolant Over temperature alert. That fixed the issue I was having. I did not need to replace the sensor after all. I've been searching for a wire diagram so I can identify which connector wires were broken, but I have been unsuccessful in finding one. But it looks like it is the wire that connects to the cylinder head temperature sensor (as indicated by code P1289) - the end of the wire closest to the top of the intake manifold. I am relieved the alert is gone, and that I saved myself from spending $600.00+.

Thank you for all the assistance, Joe. You really are awesome!

Oh, and by the way, I don't believe shredded paper in my engine was from rats. I feel it was likely a paper sucked in by engine that made its way under the rubber engine cover that could no longer "free itself" from that compartment.
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Saturday, December 29th, 2018 AT 11:54 PM
Tiny
JACOBANDNICKOLAS
  • EXPERT
I''m glad to help and glad you got it fixed. I attached the sensor wires schematic which stretch across several pages of schematics. If you need or want something specific, let me know.

Take care,
Joe
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Sunday, December 30th, 2018 AT 2:11 PM

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