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INFINITI QX4 Thermostat

6 items

Upgrade your vehicle's thermostat with A-Premium's high-quality options. Choose reliability and durability for a smoother ride.

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Engine Coolant Thermostat Housing with Gasket for Infiniti G35 Nissan PathfinderEngine Coolant Thermostat Housing with Gasket for Infiniti G35 Nissan Pathfinder
A-Premium®Part # APTHA0018
Engine Coolant Thermostat Housing with Gasket for Infiniti G35 Nissan Pathfinder
4.685 Reviews
$28.99
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2-year warranty
90 days free return
Fits 2003 - 2008 Infiniti FX35, 2003 - 2007 Infiniti G35, 2003 - 2003 Infiniti G35, 2007 - 2007 Infiniti G35, 2001 - 2003 Infiniti QX4, 2004 - 2006 Nissan 350Z, 2003 - 2006 Nissan 350Z, 2001 - 2004 Nissan Pathfinder
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Vehicle: INFINITI QX4
Item LocatedUnited States
Quantity1
MaterialMetal
ColorNatural
item #1003CZCY
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A-Premium APTHE083 Engine Coolant Thermostat
A-Premium®Part # APTHE083
A-Premium APTHE083 Engine Coolant Thermostat
4.685 Reviews
$25.99
Low stock: Only 2 left
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2-year warranty
90 days free return
Fits 1997 - 2000 INFINITI QX4, 1999 - 2000 Nissan Frontier, 2001 - 2003 Nissan Frontier, 2001 - 2004 Nissan Frontier, 2004 - 2004 Nissan Frontier, 1996 - 2000 Nissan Pathfinder, 1995 - 1998 Nissan Quest, 1999 - 2002 Nissan Quest, 2000 - 2004 Nissan Xterra
Add Trim and Engine info to ensure a guaranteed fit
Vehicle: INFINITI QX4
Item LocatedUnited States
Quantity1
MaterialMetal and Rubber
ConditionNew
item #1005V38P
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Beck/Arnley 143-0833 Engine Coolant Thermostat
Beck/ArnleyPart # 143-0833
Beck/Arnley 143-0833 Engine Coolant Thermostat
51 Reviews
$32.99
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3-year warranty
90 days free return
Fits 2001-2003 INFINITI QX4, 2000-2001 Nissan Maxima, 2001-2004 Nissan Pathfinder, 2002-2006 Nissan Altima, 2002-2006 Nissan Sentra, 2007-2008 Nissan Altima, 2007-2008 Nissan Altima, 2007-2008 Nissan Altima, 2007-2008 Nissan Versa, 2007-2012 Nissan Sentra, 2008-2016 Nissan Rogue, 2009-2009 Nissan Altima, 2009-2012 Nissan Versa, 2009-2014 Nissan Cube, 2010-2011 Nissan Altima, 2010-2011 Nissan Altima, 2010-2011 Nissan Altima, 2011-2013 Nissan Juke, 2012-2013 Nissan Altima, 2014-2015 Nissan Rogue Select
Add Trim and Engine info to ensure a guaranteed fit
Vehicle: INFINITI QX4
Item LocatedUnited States
QuantityOne Set
Part interchange
143-0833
item #1000XHTY
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Beck/Arnley 143-0721 Engine Coolant Thermostat
Beck/ArnleyPart # 143-0721
Beck/Arnley 143-0721 Engine Coolant Thermostat
51 Reviews
$30.99
Edit ZIP code
3-year warranty
90 days free return
Fits 1990-1992 INFINITI M30, 1993-1997 INFINITI J30, 1997-2000 INFINITI QX4, 1997-2001 INFINITI Q45, 1993-1999 Mercury Villager, 1984-1996 Nissan 300ZX, 1985-1994 Nissan Maxima, 1986-1994 Nissan D21, 1987-1988 Nissan 200SX, 1987-1988 Nissan Pathfinder, 1989-1995 Nissan Pathfinder, 1993-2002 Nissan Quest, 1995-1995 Nissan Pickup, 1996-2000 Nissan Pathfinder, 1999-2004 Nissan Frontier, 2000-2004 Nissan Xterra
Add Trim and Engine info to ensure a guaranteed fit
Vehicle: INFINITI QX4
Item LocatedUnited States
Quantity1
Part interchange
143-0721
item #1000XETQ
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Engine Coolant Thermostat - Mahle TI 256 77D
MahlePart # TI 256 77D
Engine Coolant Thermostat - Mahle TI 256 77D
51 Reviews
$40.99
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3-year warranty
90 days free return
Fits 2001-2003 INFINITI QX4, 2003-2006 INFINITI G35, 2003-2008 INFINITI FX35, 2007-2007 INFINITI G35, 2008-2008 INFINITI G37, 2001-2004 Nissan Pathfinder, 2003-2006 Nissan 350Z
Add Trim and Engine info to ensure a guaranteed fit
Vehicle: INFINITI QX4
Item LocatedUnited States
Quantity1
Part interchange
TI 256 77D, 21200-4W000, 21200-4W010, 21200-4W01B, 33940, 14668, TI25677D, 391-170
item #1000XQZN
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Engine Coolant Thermostat - Upper - Mahle TX 168 95
MahlePart # TX 168 95
Engine Coolant Thermostat - Upper - Mahle TX 168 95
51 Reviews
$29.99
Edit ZIP code
3-year warranty
90 days free return
Fits 2000-2001 INFINITI I30, 2001-2003 INFINITI QX4, 2002-2005 INFINITI Q45, 2003-2004 INFINITI M45, 2003-2008 INFINITI FX45, 2006-2006 INFINITI Q45, 2006-2010 INFINITI M45, 2000-2001 Nissan Maxima, 2001-2004 Nissan Pathfinder, 2002-2006 Nissan Sentra, 2002-2013 Nissan Altima, 2007-2008 Nissan Versa, 2007-2012 Nissan Sentra, 2008-2014 Nissan Rogue, 2009-2010 Nissan Versa, 2009-2011 Nissan Cube, 2011-2012 Nissan Juke, 2012-2012 Nissan Cube, 2013-2013 Nissan Juke, 2014-2014 Nissan Rogue Select
Add Trim and Engine info to ensure a guaranteed fit
Vehicle: INFINITI QX4
Item LocatedUnited States
Quantity1
Installation PositionUpper
Part interchange
TX 168 95, 21230-6N20A, 34160, 15112, TX16895, 7302-180
item #1000XP8C
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What is an engine thermostat?

 While all engines can become too hot, if your thermostat isn't working correctly, your engine's well-being is at serious risk. The engine thermostat, often simply referred to as a thermostat, regulates the engine's operating temperature within an optimal range (typically around 195 to 220 degrees Fahrenheit).

How does a car thermostat work?

As a temperature-sensitive valve within the cooling system, a car thermostat responds to changes in coolant temperature. Understanding how it works by the following breakdown steps:

  • Closed position (cold start)

Initially closed to help the engine warm up quickly.

  • Heating up

The engine generates heat during operation.

  • Opening the thermostat

A temperature-sensitive element (usually wax) causes the thermostat to open gradually.

  • Coolant flow

When open, coolant flows from the engine to the radiator.

  • Maintaining optimal temperature

Adjusts coolant flow to maintain the ideal engine temperature.

  • Temperature regulation

Continuously adjusts to prevent overheating and ensure efficient operation.

Signs of a bad thermostat

  1. Overheating: The engine becomes excessively hot due to a stuck-closed thermostat.
  2. Low or fluctuating temperature: A thermostat stuck open results in a cooler engine, affecting fuel efficiency and heating.
  3. Temperature warning light: Illuminates to indicate engine overheating due to a faulty thermostat.
  4. Poor fuel efficiency: Stuck-open thermostat reduces fuel efficiency as the engine operates less efficiently at lower temperatures.
  5. Inadequate cabin heating: Insufficient cabin heating in cold weather with a thermostat that's stuck open.
  6. Coolant leaks: Gasket or sealing issues can lead to coolant leaks.
  7. Rapid temperature fluctuations: The gauge shows rapid swings between hot and cold.
  8. Engine running hot at idle: Higher engine temperature during idle or in traffic due to restricted coolant flow.
  9. Slow or inconsistent warm-up: Longer-than-normal warm-up times, even in moderate weather.
  10. Inconsistent heater operation: This affects the performance of the vehicle's heater, causing inconsistent or inadequate heating in cold weather.

Related Blogs

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Learn why coolant boils or bubbles after you turn the engine off, how heat soak affects the cooling system, and how to diagnose leaks, trapped air, cap, thermostat, fan, water pump, or head gasket problems.

Jul 29, 2026