How to replace and check a Coolant Temperature Sensor on Mercury Mariner?

The coolant temperature indicator system includes a dash warning light or gauge and a temperature sending unit on the engine. Four-cylinder and post-2008 V6 models use a Cylinder Head Temperature sensor, while pre-2009 V6 models use an Engine Coolant Temperature sensor. These sensors inform the Powertrain Control Module and function as the coolant temperature sending unit. If overheating is indicated, check the coolant level and wiring harness connectors. The indicator light should come on when the ignition is turned to START and go out once the engine starts, unless the engine overheats. If the light doesn't behave as expected, it could be due to a faulty bulb, ignition switch, circuit, grounded wire, or sending unit. Ensure the coolant is correctly mixed to activate the sending unit.

Genuine Mercury Mariner Coolant Temperature Sensor

Coolant Water Temperature Sensor

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Mercury Mariner Sender Assembly
Part Number: 3F1Z-12A648-A
$25.76 MSRP: $41.09
You Save: $15.33 (38%)
Ships in 1 Business Day
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Product Specifications
- Other Name: Sender Assy
- Replaces: F5AZ-12A648-AB, F5AZ-12A648-A
- Warranty: This genuine part is guaranteed by Ford's factory warranty.
Fits the following Vehicles:
- 2005-2011 Mercury Mariner | 4 Cyl 2.3L, 4 Cyl 2.3L Hybrid Gas/Electric DOHC, 4 Cyl 2.5L Duratec (110kW/150PS), 4 Cyl 2.5L PFI Gas/Electric, 6 Cyl 3.0L DOHC EFI Modular, 6 Cyl 3.0L OHC Duratec | CVT Auto Trans Powersplit Elec, Four-Wheel Drive (Full Time) (Left Hand Drive), Front-Wheel Drive (Left Hand Drive), Left Hand Drive
View related parts
Mercury Mariner Sender Assembly
Part Number: F5AZ-12A648-AB
$25.76 MSRP: $41.09
You Save: $15.33 (38%)
Ships in 1 Business Day
ADD TO CART
Product Specifications
- Other Name: Sender Assy
- Replaced by: 3F1Z-12A648-A
- Warranty: This genuine part is guaranteed by Ford's factory warranty.
Fits the following Vehicles:
- 2005-2010 Mercury Mariner | 4 Cyl 2.3L, 4 Cyl 2.3L Hybrid Gas/Electric DOHC, 4 Cyl 2.5L Duratec (110kW/150PS), 4 Cyl 2.5L PFI Gas/Electric, 6 Cyl 3.0L DOHC EFI Modular, 6 Cyl 3.0L OHC Duratec | CVT Auto Trans Powersplit Elec, Four-Wheel Drive (Full Time) (Left Hand Drive), Front-Wheel Drive (Left Hand Drive), Left Hand Drive
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Mercury Mariner Sensor - Engine Coolant Temperature
Part Number: 3L8Z-12A648-AA
$15.96 MSRP: $25.45
You Save: $9.49 (38%)
Ships in 1-2 Business Days
ADD TO CART
Product Specifications
- Manufacturer Note: Rectangular connector with 2 flat pins, DOHC
- Warranty: This genuine part is guaranteed by Ford's factory warranty.
Fits the following Vehicles:
- 2005-2008 Mercury Mariner | 6 Cyl 3.0L DOHC EFI Modular | 4AT CD4E, 5-Speed Manual Transmission, 5-Speed Manual Transmission - AK, 6-Speed Automatic Transmission 6F Mid-Range, CVT Auto Trans Powersplit Elec, Four-Wheel Drive (Full Time) (Left Hand Drive), Four-Wheel Drive (Right Hand Drive), Front-Wheel Drive (Left Hand Drive), Left Hand Drive, Two-Wheel Drive (Left Hand Drive), Two-Wheel Drive (Right Hand Drive)
View related parts
Mercury Mariner Sender Assembly - Temperature
Part Number: F68Z-10884-AA
$37.15 MSRP: $73.82
You Save: $36.67 (50%)
ADD TO CART
Product Specifications
- Warranty: This genuine part is guaranteed by Ford's factory warranty.
Fits the following Vehicles:
- 2005-2008 Mercury Mariner | 6 Cyl 3.0L DOHC EFI Modular | 4AT CD4E, 5-Speed Manual Transmission, 5-Speed Manual Transmission - AK, 6-Speed Automatic Transmission 6F Mid-Range, CVT Auto Trans Powersplit Elec, Four-Wheel Drive (Full Time) (Left Hand Drive), Four-Wheel Drive (Right Hand Drive), Front-Wheel Drive (Left Hand Drive), Left Hand Drive, Two-Wheel Drive (Left Hand Drive), Two-Wheel Drive (Right Hand Drive)

Mercury Mariner Coolant Temperature Sensor Parts Questions & Experts Answers

Sender Assembly
F5AZ-12A648-AB
Q: How to replace and check a Coolant Temperature Sensor on Mercury Mariner?
A: The coolant temperature indicator system includes a dash warning light or gauge and a temperature sending unit on the engine. Four-cylinder and post-2008 V6 models use a Cylinder Head Temperature sensor, while pre-2009 V6 models use an Engine Coolant Temperature sensor. These sensors inform the Powertrain Control Module and function as the coolant temperature sending unit. If overheating is indicated, check the coolant level and wiring harness connectors. The indicator light should come on when the ignition is turned to START and go out once the engine starts, unless the engine overheats. If the light doesn't behave as expected, it could be due to a faulty bulb, ignition switch, circuit, grounded wire, or sending unit. Ensure the coolant is correctly mixed to activate the sending unit.