SPONSORED LINKS

I am trying to figure out where the engine coolant sensor is located?

Tiny
NHILTON1
  • MEMBER
  • 2005 CHEVROLET TRAILBLAZER
  • 106,888 MILES
The engine is a V6, and the upper radiator hose is slightly to the passenger side, and hubby says the thermostat is there, I can't seem to find the sensor, a picture would be great if you have one, as I am going insane and want to fix it in the morning myself. Any help would be greatly appreciated. What all do I need to take apart, the videos on youtube does not help either they are not car specific.

I would make a donation if I could, I have already spent a fortune on this vehicle as you can well guess from all of the issues that the Trailblazers have.
SPONSORED LINKS
Friday, October 7th, 2011 AT 12:02 AM

29 Replies

Tiny
SATURNTECH9
  • MECHANIC
  • 30,869 POSTS
Left front of engine block near alternator its screwed into the head no specials tools just a deep socket. Here are the diagrams below to show you where the coolant temperature sensor is on both 6 and 8 cylinder engines. Check out the diagrams (Below). Please let us know what you find.
Images (Click to make bigger)
Thumb
Thumb
SPONSORED LINKS
Was this
answer
helpful?
Yes
No
Saturday, October 21st, 2017 AT 1:01 PM
Tiny
NHILTON1
  • MEMBER
  • 2 POSTS
But you need more tools I assume you have to remove the alternator
Was this
answer
helpful?
Yes
No
+1
Saturday, October 21st, 2017 AT 1:01 PM
Tiny
SATURNTECH9
  • MECHANIC
  • 30,869 POSTS
Do you have the 4.2L or the 5.3L engine?Because I just caught you out 6 as the engine I thought you put 8 so thats the location I gave the sensor for. The trailblazer has a inline 6 or V8 engine. If you have a 6 cylinder is a inline 6.
Was this
answer
helpful?
Yes
No
+1
Saturday, October 21st, 2017 AT 1:01 PM
Tiny
EDUALAV
  • MEMBER
  • 1 POST
  • 2003 CHEVROLET TRAILBLAZER
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 110,556 MILES
Hoe yo install coolant temperature sensor
Was this
answer
helpful?
Yes
No
Monday, November 2nd, 2020 AT 3:25 PM (Merged)
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
ENGINE COOLANT TEMPERATURE (ECT) SENSOR REPLACEMENT

REMOVAL PROCEDURE
NOTE: Use care when handling the coolant sensor. Damage to the coolant sensor will affect the operation of the fuel control system.

1. Turn the engine OFF.
2. Disconnect the negative battery terminal. CAUTION: Refer to Battery Disconnect Caution in Service Precautions.
3. Drain coolant below the level of the ECT sensor. Refer to Draining and Filling Cooling System (Body Vin Code 6)Draining and Filling Cooling System (Body Vin Code 3) in Cooling System.
4. Disconnect the ECT sensor electrical connector (1).
5. Remove the drive belt and the generator.
6. Carefully remove the ECT sensor (1).

INSTALLATION PROCEDURE
NOTE:
*Use care when handling the coolant sensor. Damage to the coolant sensor will affect the operation of the fuel control system.
*Replacement components must be the correct part number for the application. Components requiring the use of the thread locking compound, lubricants, corrosion inhibitors, or sealants are identified in the service procedure. Some replacement components may come with these coatings already applied. Do not use these coatings on components unless specified. These coatings can affect the final torque, which may affect the operation of the component. Use the correct torque specification when installing components in order to avoid damage.
1. If installing the original sensor or a new sensor without sealant, apply thread sealer P/N 12346004 or equivalent.
2. Install the ECT sensor. NOTE: Refer to Fastener Notice in Service Precautions. Tighten Tighten the ECT sensor to 16 N.M (12 lb ft).
3. Connect the ECT electrical connector (1).
4. Install the generator and the drive belt.
5. Connect the negative battery terminal.
6. Refill the engine coolant. Refer to Draining and Filling Cooling System (Body Vin Code 6)Draining and Filling Cooling System (Body Vin Code 3) in Cooling System.
SPONSORED LINKS
Was this
answer
helpful?
Yes
No
Monday, November 2nd, 2020 AT 3:25 PM (Merged)
Tiny
BIKERTHUG
  • MEMBER
  • 2 POSTS
  • 2003 CHEVROLET TRAILBLAZER
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 64,000 MILES
Where is the coolant temp sensor located
Was this
answer
helpful?
Yes
No
Monday, November 2nd, 2020 AT 3:25 PM (Merged)
Tiny
IMPALASS
  • MECHANIC
  • 3,112 POSTS
Hello - bikerthug

Here is the info you requested

Hope this helps.

If you would like to offer feedback on your experience with me/us - feel free to go into the blue "Give Feedback" area under ImpalaSS


https://www.2carpros.com/forum/automotive_pictures/248015_102980753_1.jpg



ENGINE COOLANT TEMPERATURE (ECT) SENSOR REPLACEMENT

REMOVAL PROCEDURE

NOTE: Use care when handling the coolant sensor. Damage to the coolant sensor will affect the operation of the fuel control system.

Turn the engine OFF.
Disconnect the negative battery terminal. CAUTION: Refer to Battery Disconnect Caution in Service Precautions.
Drain coolant below the level of the ECT sensor. Refer to Draining and Filling Cooling System (Body Vin Code 6)Draining and Filling Cooling System (Body Vin Code 3) in Cooling System.


https://www.2carpros.com/forum/automotive_pictures/248015_1_29.jpg



Disconnect the ECT sensor electrical connector (1).
Remove the drive belt and the generator.


https://www.2carpros.com/forum/automotive_pictures/248015_2_21.jpg



Carefully remove the ECT sensor (1).
INSTALLATION PROCEDURE

NOTE:

Use care when handling the coolant sensor. Damage to the coolant sensor will affect the operation of the fuel control system.
Replacement components must be the correct part number for the application. Components requiring the use of the thread locking compound, lubricants, corrosion inhibitors, or sealants are identified in the service procedure. Some replacement components may come with these coatings already applied. Do not use these coatings on components unless specified. These coatings can affect the final torque, which may affect the operation of the component. Use the correct torque specification when installing components in order to avoid damage.
If installing the original sensor or a new sensor without sealant, apply thread sealer P/N 12346004 or equivalent.


https://www.2carpros.com/forum/automotive_pictures/248015_3_18.jpg



Install the ECT sensor. NOTE: Refer to Fastener Notice in Service Precautions. Tighten Tighten the ECT sensor to 16 N.m (12 lb ft) .


https://www.2carpros.com/forum/automotive_pictures/248015_4_9.jpg



Connect the ECT electrical connector (1).
Install the generator and the drive belt.
Connect the negative battery terminal.
Refill the engine coolant. Refer to Draining and Filling Cooling System (Body Vin Code 6)Draining and Filling Cooling System (Body Vin Code 3) in Cooling System.
Was this
answer
helpful?
Yes
No
+2
Monday, November 2nd, 2020 AT 3:25 PM (Merged)
Tiny
BIKERTHUG
  • MEMBER
  • 2 POSTS
  • 2003 CHEVROLET TRAILBLAZER
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 64,000 MILES
Where is this coolant temp sensor located
Was this
answer
helpful?
Yes
No
Monday, November 2nd, 2020 AT 3:25 PM (Merged)
Tiny
BLACKOP555
  • MECHANIC
  • 10,371 POSTS
Front right engine block near the generator. See picture bellow.
Was this
answer
helpful?
Yes
No
-1
Monday, November 2nd, 2020 AT 3:25 PM (Merged)
Tiny
BLACKOP555
  • MECHANIC
  • 10,371 POSTS


https://www.2carpros.com/forum/automotive_pictures/66751_ects_1.jpg

Was this
answer
helpful?
Yes
No
+5
Monday, November 2nd, 2020 AT 3:25 PM (Merged)
Tiny
JASONN
  • MEMBER
  • 1 POST
  • 2003 CHEVROLET TRAILBLAZER
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 87,000 MILES
Where and how to change a coolent temp. Sensor on my 03 trailblazer.
Was this
answer
helpful?
Yes
No
Monday, November 2nd, 2020 AT 3:25 PM (Merged)
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS


https://www.2carpros.com/forum/automotive_pictures/12900_ect_14.jpg



ENGINE COOLANT TEMPERATURE (ECT) SENSOR REPLACEMENT

REMOVAL PROCEDURE
NOTE: Use care when handling the coolant sensor. Damage to the coolant sensor will affect the operation of the fuel control system.

1.Turn the engine OFF.
2.Disconnect the negative battery terminal. CAUTION: Refer to Battery Disconnect Caution in Service Precautions.
3.Drain coolant below the level of the ECT sensor. Refer to Draining and Filling Cooling System (Body Vin Code 6)Draining and Filling Cooling System (Body Vin Code 3) in Cooling System.
4.Disconnect the ECT sensor electrical connector (1).
5.Remove the drive belt and the generator.
6.Carefully remove the ECT sensor (1).

INSTALLATION PROCEDURE
NOTE:
*Use care when handling the coolant sensor. Damage to the coolant sensor will affect the operation of the fuel control system.
*Replacement components must be the correct part number for the application. Components requiring the use of the thread locking compound, lubricants, corrosion inhibitors, or sealants are identified in the service procedure. Some replacement components may come with these coatings already applied. Do not use these coatings on components unless specified. These coatings can affect the final torque, which may affect the operation of the component. Use the correct torque specification when installing components in order to avoid damage.
1.If installing the original sensor or a new sensor without sealant, apply thread sealer P/N 12346004 or equivalent.
2.Install the ECT sensor. NOTE: Refer to Fastener Notice in Service Precautions. Tighten Tighten the ECT sensor to 16 N.m (12 lb ft) .
3.Connect the ECT electrical connector (1).
4.Install the generator and the drive belt.
5.Connect the negative battery terminal.
6.Refill the engine coolant. Refer to Draining and Filling Cooling System (Body Vin Code 6)Draining and Filling Cooling System (Body Vin Code 3) in Cooling System.

SPONSORED LINKS
Was this
answer
helpful?
Yes
No
Monday, November 2nd, 2020 AT 3:25 PM (Merged)
Tiny
KEMA30
  • MEMBER
  • 1 POST
  • 2003 CHEVROLET TRAILBLAZER
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 106,800 MILES
My engine check light is on, and I took it to get a diagnostic test and they said the coolant sensor is defective. Where on my vehichle is this sensor located?
Was this
answer
helpful?
Yes
No
Monday, November 2nd, 2020 AT 3:25 PM (Merged)
Tiny
DENNYP
  • MECHANIC
  • 1,824 POSTS


https://www.2carpros.com/forum/automotive_pictures/102900_coolant_1.jpg



(1) Engine Coolant Temperature (ECT) Sensor
(2) Engine Harness
(3) PCM C1
(4) PCM C2
(5) Powertrain Control Module (PCM) C3
Was this
answer
helpful?
Yes
No
Monday, November 2nd, 2020 AT 3:25 PM (Merged)
Tiny
DENNYP
  • MECHANIC
  • 1,824 POSTS
Number 1 shows the connector for the sensor. You will find the sensor mounts to the engine just behind the alternator.
Was this
answer
helpful?
Yes
No
+1
Monday, November 2nd, 2020 AT 3:25 PM (Merged)
Tiny
JCATRON
  • MEMBER
  • 8 POSTS
  • 2002 CHEVROLET TRAILBLAZER
  • 4.2L
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 200,000 MILES
I replaced the engine which is an 2008-2009, but the head is for an 2002 4.2L. There are no ports for the water temperature sensor to go due to the change in design from Cheverolet. Is there another port I can use in the block for this sensor?
Was this
answer
helpful?
Yes
No
Monday, November 2nd, 2020 AT 3:26 PM (Merged)
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Good morning.

I attached a picture of the location of the coolant sensor for the 2002 for you to view. It needs to go there and cannot be relocated.

Roy
Image (Click to make bigger)
Thumb
Was this
answer
helpful?
Yes
No
Monday, November 2nd, 2020 AT 3:26 PM (Merged)
Tiny
JCATRON
  • MEMBER
  • 8 POSTS
I know where the stock sensor location is. I do not think you understand the question. There is no threaded water temperature sensor ports on both my block or my head.
Was this
answer
helpful?
Yes
No
+1
Monday, November 2nd, 2020 AT 3:26 PM (Merged)
Tiny
JCATRON
  • MEMBER
  • 8 POSTS
So Roy, do I drill and tap the 2008 block to put in that location? Or is there another passage on the block that can be used? There is a plug beside the thermostat to the right
Was this
answer
helpful?
Yes
No
+1
Monday, November 2nd, 2020 AT 3:26 PM (Merged)
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
I posted the picture for the 2002. Is that what you installed?

If it is next to the thermostat, yes as that is the location of the sensor. Make sure you use a pipe thread tap.

Roy
Was this
answer
helpful?
Yes
No
Monday, November 2nd, 2020 AT 3:26 PM (Merged)

Please login or register to post a reply.

Related Coolant Temperature Sensor Content

Coolant Temperature Sender Replacement
VIDEO
Coolant Temperature Sender Replacement
Instructional repair video
Coolant Temperature Sensor Symptoms
GUIDE
Coolant Temperature Sensor Symptoms
An automotive engine coolant temperature sensor, (ECT) sensor, or sometimes called a cylinder head temperature sensor is used to generate feedback information to the PCM...
VIEW MORE

Sponsored links