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Audi A4 Thermostat

47 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 - Mahle TX 30 87DEngine Coolant Thermostat - Mahle TX 30 87D
MahlePart # TX 30 87D
Engine Coolant Thermostat - Mahle TX 30 87D
51 Reviews
$28.99
Edit ZIP code
3-year warranty
90 days free return
Fits 1990-1994 Audi V8 Quattro, 1992-1994 Audi 100, 1992-1994 Audi 100 Quattro, 1993-1994 Audi 90, 1993-1994 Audi 90 Quattro, 1994-1998 Audi Cabriolet, 1995-1999 Audi A6, 1995-1999 Audi A6 Quattro, 1996-1996 Audi A4, 1996-1996 Audi A4 Quattro, 1997-1999 Audi A4, 1997-1999 Audi A4 Quattro, 2000-2001 Audi A4, 2000-2001 Audi A4 Quattro, 2000-2001 Audi A6, 2000-2001 Audi A6 Quattro, 2000-2002 Audi S4, 2000-2004 Audi A6 Quattro, 2001-2002 Audi Allroad Quattro, 2003-2005 Audi Allroad Quattro
Add Trim and Engine info to ensure a guaranteed fit
Vehicle: Audi A4
Item LocatedUnited States
Quantity1
Part interchange
TX 30 87D, 4236.88D, 33975, 48049, TX3087D, 304-192, 078 121 113 F, 2.145.87.312
item #1000XRPC
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Engine Coolant Thermostat - Mahle TM 3 100
MahlePart # TM 3 100
Engine Coolant Thermostat - Mahle TM 3 100
51 Reviews
$94.99
Edit ZIP code
3-year warranty
90 days free return
Fits 2002-2005 Audi A4 Quattro, 2002-2006 Audi A4, 2005-2005 Audi A4, 2005-2005 Audi A4 Quattro
Add Trim and Engine info to ensure a guaranteed fit
Vehicle: Audi A4
Item LocatedUnited States
Quantity1
Part interchange
TM 3 100, 34047, 48732, 601-212, 06B 121 111 K, TM3100, 1.774.03
item #1000XRKL
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Engine Coolant Thermostat - Mahle TX 353 95
MahlePart # TX 353 95
Engine Coolant Thermostat - Mahle TX 353 95
51 Reviews
$33.99
Edit ZIP code
3-year warranty
90 days free return
Fits 2008-2009 Audi A3, 2009-2009 Audi A3 Quattro, 2009-2009 Audi TT, 2009-2009 Audi TT Quattro, 2009-2014 Audi A4 Quattro, 2009-2016 Audi A4, 2010-2010 Audi A3, 2010-2011 Audi A3, 2010-2011 Audi A3, 2010-2013 Audi A3, 2010-2013 Audi A3, 2010-2013 Audi A3 Quattro, 2010-2013 Audi TT Quattro, 2011-2012 Audi Q5, 2012-2013 Audi A3, 2012-2013 Audi A6, 2012-2014 Audi A5, 2012-2016 Audi A5 Quattro, 2013-2015 Audi A6 Quattro, 2013-2015 Audi allroad
Add Trim and Engine info to ensure a guaranteed fit
Vehicle: Audi A4
Item LocatedUnited States
Quantity1
Part interchange
TX 353 95, 34804, 707-203, TX35395, 06H 121 113 B
item #1000XSGN
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Engine Coolant Thermostat - Mahle TX 14 87D
MahlePart # TX 14 87D
Engine Coolant Thermostat - Mahle TX 14 87D
51 Reviews
$22.99
Edit ZIP code
3-year warranty
90 days free return
Fits 1997-2001 Audi A4, 1997-2001 Audi A4 Quattro, 2000-2002 Audi TT Quattro, 2000-2006 Audi TT, 1998-2005 Volkswagen Beetle, 1998-2005 Volkswagen Passat, 1999-2005 Volkswagen Beetle, 1999-2005 Volkswagen Jetta, 1999-2006 Volkswagen Golf, 2000-2005 Volkswagen Jetta, 2000-2006 Volkswagen Golf, 2007-2009 Volkswagen Jetta City, 2007-2010 Volkswagen Golf City, 2011-2011 Volkswagen Jetta, 2011-2011 Volkswagen Jetta, 2011-2011 Volkswagen Jetta, 2011-2013 Volkswagen Jetta, 2011-2015 Volkswagen Jetta, 2011-2015 Volkswagen Jetta, 2012-2015 Volkswagen Jetta
Add Trim and Engine info to ensure a guaranteed fit
Vehicle: Audi A4
Item LocatedUnited States
Quantity1
Part interchange
TX 14 87D, 3141.87D, 34762, 14419, 050 121 113 C, TX1487D, 200-192, 1.180.87.302
item #1000XRA4
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Engine Coolant Thermostat - Mahle TX 30 71D
MahlePart # TX 30 71D
Engine Coolant Thermostat - Mahle TX 30 71D
51 Reviews
$32.99
Edit ZIP code
3-year warranty
90 days free return
Fits 1990-1994 Audi V8 Quattro, 1992-1994 Audi 100, 1992-1994 Audi 100 Quattro, 1993-1994 Audi 90, 1993-1994 Audi 90 Quattro, 1994-1998 Audi Cabriolet, 1995-1999 Audi A6 Quattro, 1995-2001 Audi A6, 1996-1996 Audi A4, 1996-1996 Audi A4 Quattro, 1997-2001 Audi A4, 1997-2001 Audi A4 Quattro, 2000-2001 Audi A6 Quattro, 2000-2002 Audi S4, 2000-2004 Audi A6 Quattro, 2001-2002 Audi Allroad Quattro, 2003-2005 Audi Allroad Quattro, 1998-2005 Volkswagen Passat
Add Trim and Engine info to ensure a guaranteed fit
Vehicle: Audi A4
Item LocatedUnited States
Quantity1
Part interchange
TX 30 71D, 4235.71D, TX3071D, 2.145.71.312
item #1000XSE0
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Vemo V15-99-1897 Engine Coolant Thermostat Kit
VemoPart # V15-99-1897
Vemo V15-99-1897 Engine Coolant Thermostat Kit
57 Reviews
$79.99
Edit ZIP code
3-year warranty
90 days free return
Fits 2005-2005 Audi A4, 2005-2005 Audi A4 Quattro, 2005-2005 Audi A4 Quattro, 2005-2005 Audi A4 Quattro, 2005-2005 Audi A4 Quattro, 2005-2005 Audi A4 Quattro, 2005-2005 Audi A4 Quattro, 2005-2005 Audi A4 Quattro, 2006-2007 Audi A4, 2006-2008 Audi A4, 2006-2008 Audi A4 Quattro, 2006-2008 Audi A4 Quattro, 2007-2009 Audi A4, 2007-2009 Audi A4 Quattro, 2008-2008 Audi A4
Add Trim and Engine info to ensure a guaranteed fit
Vehicle: Audi A4
Item LocatedUnited States
Quantity1
Part interchange
V15-99-1897, 132987, TI787, 78668, CTA0016, 57687, 1601325914, 34069, 
...View more
item #1000X9GA
Note
With seal
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Vemo V15-99-2068 Engine Coolant Thermostat
VemoPart # V15-99-2068
Vemo V15-99-2068 Engine Coolant Thermostat
57 Reviews
$80.99
Edit ZIP code
3-year warranty
90 days free return
Fits 2008-2013 Audi A3, 2009-2009 Audi A3 Quattro, 2009-2009 Audi TT, 2009-2009 Audi TT Quattro, 2009-2012 Audi A4 Quattro, 2009-2014 Audi A4, 2009-2014 Audi A4 Quattro, 2010-2011 Audi A3 Quattro, 2010-2013 Audi TT Quattro, 2011-2015 Audi Q5, 2011-2015 Audi Q5, 2012-2012 Audi A6, 2012-2013 Audi A3 Quattro, 2012-2014 Audi A5, 2012-2014 Audi A5 Quattro, 2012-2014 Audi A5 Quattro, 2013-2014 Audi A6, 2013-2014 Audi A6, 2013-2014 Audi A6 Quattro, 2013-2015 Audi Q5
Add Trim and Engine info to ensure a guaranteed fit
Vehicle: Audi A4
Item LocatedUnited States
Quantity1
Part interchange
V15-99-2068, 78743, CTI0010, 06H121119B, 06H121119BS1, 6H121119BS1, 6H121119B, 34782, 
...View more
item #1001QLDH
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Page 3 of 3

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.

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Jul 29, 2026