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Thermostat

310 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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A-Premium APTHE019 Engine Coolant ThermostatA-Premium APTHE019 Engine Coolant Thermostat
A-Premium®Part # APTHE019
A-Premium APTHE019 Engine Coolant Thermostat
52 Reviews
CA$31.99
Enter ZIP codeFree standard shipping
2-year warranty
90 days free return
Fits 2023 - 2024 Dodge Durango, 2023 - 2024 Dodge Durango, 2023 - 2024 Dodge Durango, 2023 - 2023 Chrysler 300, 2023 - 2023 Chrysler 300, 2023 - 2023 Dodge Challenger, 2023 - 2023 Dodge Challenger, 2023 - 2023 Dodge Challenger, 2023 - 2023 Dodge Charger, 2023 - 2023 Dodge Charger, 2023 - 2023 Dodge Charger, 2023 - 2023 Jeep Wrangler, 2023 - 2023 Ram 1500, 2023 - 2023 Ram 1500 Classic, 2019 - 2021 Ram 1500 Classic, 2018 - 2021 Jeep Grand Cherokee, 2018 - 2020 Dodge Durango, 2015 - 2020 Dodge Challenger, 2015 - 2020 Dodge Charger, 2012 - 2021 Jeep Grand Cherokee
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Item LocatedUnited States
Quantity1
MaterialMetal and Rubber
ConditionNew
item #1005V4XS
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A-Premium APTHE017 Engine Coolant Thermostat
A-Premium®Part # APTHE017
A-Premium APTHE017 Engine Coolant Thermostat
52 Reviews
CA$22.99
Enter ZIP codeFree standard shipping
2-year warranty
90 days free return
Fits 2008 - 2009 Ford F-650, 2008 - 2009 Ford F-750, 1999 - 2001 Toyota Solara, 1998 - 1998 Ford F-800, 1998 - 1998 Ford F-800 LPO, 1997 - 1998 Nissan 200SX, 1996 - 2000 Toyota RAV4, 1996 - 1997 Nissan Sentra, 1995 - 1995 Nissan 200SX, 1994 - 1997 Toyota Celica, 1993 - 1997 Geo Prizm, 1993 - 1997 Toyota Corolla, 1992 - 2001 Toyota Camry, 1992 - 1999 Toyota Celica, 1992 - 1999 Toyota Paseo, 1991 - 1993 Nissan NX, 1990 - 1993 Toyota Celica, 1989 - 1999 Nissan Sentra, 1989 - 1997 Geo Prizm, 1989 - 1990 Nissan Pulsar NX
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Item LocatedUnited States
Quantity1
MaterialMetal
ConditionNew
item #1005USAT
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A-Premium APTHE011 Engine Coolant Thermostat
A-Premium®Part # APTHE011
A-Premium APTHE011 Engine Coolant Thermostat
52 Reviews
CA$41.99
Enter ZIP codeFree standard shipping
2-year warranty
90 days free return
Fits 2017 - 2018 Volkswagen Tiguan Limited, 2017 - 2017 Audi A5 Quattro, 2015 - 2018 Audi Q3, 2015 - 2018 Audi Q3 Quattro, 2015 - 2016 Audi A4, 2015 - 2016 Audi TT Quattro, 2015 - 2015 Audi A6, 2014 - 2016 Audi A4 allroad, 2014 - 2016 Audi A4 Quattro, 2014 - 2016 Volkswagen Eos, 2014 - 2015 Audi A6 Quattro, 2013 - 2017 Audi Q5, 2013 - 2017 Volkswagen CC, 2013 - 2017 Volkswagen Tiguan, 2013 - 2016 Audi allroad, 2013 - 2013 Audi A6 Quattro, 2013 - 2013 Volkswagen Tiguan, 2012 - 2016 Audi A5 Quattro, 2012 - 2014 Audi A5, 2012 - 2014 Audi A6
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Item LocatedUnited States
Quantity1
MaterialMetal and Rubber
ConditionNew
item #1005V2E3
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A-Premium APTHE032 Engine Coolant Thermostat
A-Premium®Part # APTHE032
A-Premium APTHE032 Engine Coolant Thermostat
52 Reviews
CA$30.99
Enter ZIP codeFree standard shipping
2-year warranty
90 days free return
Fits 2021 - 2023 Cadillac Escalade, 2021 - 2023 Cadillac Escalade ESV, 2021 - 2023 GMC Yukon, 2021 - 2023 GMC Yukon, 2021 - 2023 GMC Yukon XL, 2021 - 2023 GMC Yukon XL, 2021 - 2022 GMC Savana 2500, 2021 - 2022 GMC Savana 3500, 2020 - 2023 GMC Sierra 2500 HD, 2020 - 2023 GMC Sierra 3500 HD, 2019 - 2023 GMC Sierra 1500, 2019 - 2023 GMC Sierra 1500, 2019 - 2021 GMC Sierra 1500, 2019 - 2019 Mitsubishi Fuso Canter FE160, 2018 - 2021 GMC Savana 2500, 2018 - 2021 GMC Savana 3500, 2012 - 2019 Isuzu NPR-HD, 2009 - 2020 GMC Savana 4500, 2009 - 2014 Cadillac CTS, 2009 - 2013 Cadillac Escalade
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Item LocatedUnited States
Quantity1
MaterialMetal and Rubber
ConditionNew
item #1005V0PY
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Engine Coolant Thermostat for Toyota Camry RAV4 Ford Mitsubishi Scion Lexus 89℃
A-Premium®Part # APTHE071
Engine Coolant Thermostat for Toyota Camry RAV4 Ford Mitsubishi Scion Lexus 89℃
52 Reviews
CA$27.99
Enter ZIP codeFree standard shipping
2-year warranty
90 days free return
Fits 2017 - 2017 Toyota Highlander, 2016 - 2017 Toyota RAV4, 2012 - 2017 Toyota Camry, 2012 - 2012 Toyota RAV4, 2011 - 2016 Scion tC, 2011 - 2013 Toyota Sienna, 2010 - 2015 Lexus RX450h, 2010 - 2012 Lexus HS250h, 2010 - 2011 Toyota Camry, 2009 - 2016 Toyota Highlander, 2009 - 2016 Toyota Venza, 2009 - 2016 Toyota Venza, 2009 - 2015 Toyota RAV4, 2009 - 2013 Toyota Matrix, 2009 - 2012 Toyota Corolla, 2009 - 2010 Pontiac Vibe, 2008 - 2016 Toyota Highlander, 2008 - 2015 Scion xB, 2008 - 2014 Scion xD, 2007 - 2017 Lexus ES350
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Item LocatedUnited States
Quantity1
ConditionNew
item #1013DUS4
Note
Start to Open Temperature: 89℃.
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A-Premium APTHE033 Engine Coolant Thermostat
A-Premium®Part # APTHE033
A-Premium APTHE033 Engine Coolant Thermostat
52 Reviews
CA$40.99
Enter ZIP codeFree standard shipping
2-year warranty
90 days free return
Fits 2020 - 2024 Honda CR-V, 2018 - 2024 Honda Accord
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Item LocatedUnited States
Quantity1
ConditionNew
item #1005V2A3
Note
This item only fits the L4 2.L Naturally Aspirated model.
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Thermostat Housing Assembly for Ford Fusion 2014-2020 Escape 2017-2019
A-Premium®Part # APTHA0237
Thermostat Housing Assembly for Ford Fusion 2014-2020 Escape 2017-2019
52 Reviews
CA$42.99
Enter ZIP codeFree standard shipping
2-year warranty
90 days free return
Fits 2017 - 2019 Ford Escape, 2014 - 2020 Ford Fusion
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Item LocatedCanada
Quantity1
MaterialAluminum
ConditionNew
item #10027T8R
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A-Premium APTHE001 Engine Coolant Thermostat
A-Premium®Part # APTHE001
A-Premium APTHE001 Engine Coolant Thermostat
52 Reviews
CA$41.99
Enter ZIP codeFree standard shipping
2-year warranty
90 days free return
Fits 2020 - 2020 Nissan Armada, 2019 - 2020 Mitsubishi Outlander, 2016 - 2016 Nissan Frontier, 2016 - 2016 Nissan NV1500, 2016 - 2016 Nissan NV2500, 2016 - 2016 Nissan NV3500, 2015 - 2015 INFINITI Q70L, 2014 - 2016 INFINITI QX80, 2014 - 2015 INFINITI Q70, 2014 - 2014 INFINITI QX70, 2013 - 2015 Acura RDX, 2012 - 2017 Nissan NV2500, 2012 - 2017 Nissan NV3500, 2012 - 2012 Honda Crosstour, 2011 - 2013 INFINITI M56, 2010 - 2014 Acura TSX, 2010 - 2013 Acura ZDX, 2010 - 2011 Honda Accord Crosstour, 2010 - 2011 Mitsubishi Endeavor, 2009 - 2014 Acura TL
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Item LocatedUnited States
Quantity1
MaterialMetal and Rubber
ConditionNew
item #1005V2X1
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A-Premium APTHE029 Engine Coolant Thermostat
A-Premium®Part # APTHE029
A-Premium APTHE029 Engine Coolant Thermostat
52 Reviews
CA$27.99
Enter ZIP codeFree standard shipping
2-year warranty
90 days free return
Fits 2013 - 2021 Blue Bird Vision School Bus, 2006 - 2008 Lincoln Mark LT, 2005 - 2006 Mercury Monterey, 2003 - 2011 Lincoln Town Car, 2002 - 2010 Mercury Mountaineer, 2002 - 2002 Lincoln Blackwood, 1998 - 2014 Lincoln Navigator, 1994 - 1997 Mercury Cougar, 1992 - 2011 Mercury Grand Marquis, 1990 - 1991 Peugeot 405, 1989 - 1989 Peugeot 405, 1981 - 1986 Chevrolet Chevette, 1981 - 1986 Pontiac Acadian
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Item LocatedUnited States
Quantity1
MaterialMetal
ConditionNew
item #10156AP5
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Engine Coolant Thermostat Housing with Sensor for Hyundai Sonata Kia Optima 2.4L
A-Premium®Part # APTHA0133
Engine Coolant Thermostat Housing with Sensor for Hyundai Sonata Kia Optima 2.4L
52 Reviews
CA$64.99
Enter ZIP codeFree standard shipping
2-year warranty
90 days free return
Fits 2013 - 2015 Hyundai Santa Fe Sport, 2011 - 2015 Kia Optima, 2011 - 2015 Kia Sportage, 2011 - 2014 Hyundai Sonata, 2011 - 2014 Kia Sorento, 2010 - 2015 Hyundai Tucson, 2010 - 2012 Hyundai Santa Fe
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Item LocatedUnited States
ColorBlack
ConditionNew
item #10183SV0
Note
【Note-1】 This item comes with Sensor.
【Note-2】Fits Hyundai Sonata with GAS.
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Engine Coolant Thermostat for Ford F-150 Explorer Mustang E-250 Econoline
A-Premium®Part # APTHA350PG
Engine Coolant Thermostat for Ford F-150 Explorer Mustang E-250 Econoline
52 Reviews
CA$30.99
Enter ZIP codeFree standard shipping
2-year warranty
90 days free return
Fits 1995 - 1995 Ford E-350 Econoline, 1995 - 1995 Ford E-350 Econoline Club Wagon, 1994 - 1995 Ford F-250, 1994 - 1995 Ford F-350, 1994 - 1994 Ford Aerostar, 1994 - 1994 Ford Aerostar, 1994 - 1994 Ford Aspire, 1994 - 1994 Ford Bronco, 1994 - 1994 Ford Bronco, 1994 - 1994 Ford Crown Victoria, 1994 - 1994 Ford E-150 Econoline, 1994 - 1994 Ford E-150 Econoline, 1994 - 1994 Ford E-150 Econoline, 1994 - 1994 Ford E-150 Econoline Club Wagon, 1994 - 1994 Ford E-150 Econoline Club Wagon, 1994 - 1994 Ford E-150 Econoline Club Wagon, 1994 - 1994 Ford E-250 Econoline, 1994 - 1994 Ford E-250 Econoline, 1994 - 1994 Ford E-350 Econoline, 1994 - 1994 Ford E-350 Econoline
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Item LocatedUnited States
Quantity1
ConditionNew
item #1018A6WH
Note
Start to Open Temperature: 88℃.
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Thermostat Housing Assembly for Mercedes-Benz C-class W211 W212 E-class W211
A-Premium®Part # APTHA0053
Thermostat Housing Assembly for Mercedes-Benz C-class W211 W212 E-class W211
52 Reviews
CA$77.99
CA$91.99
Enter ZIP codeFree standard shipping
2-year warranty
90 days free return
Fits 2012 - 2013 Mercedes-Benz S350, 2012 - 2012 Mercedes-Benz C250, 2010 - 2013 Mercedes-Benz S400, 2010 - 2012 Mercedes-Benz C250, 2010 - 2011 Mercedes-Benz C300, 2010 - 2011 Mercedes-Benz ML350, 2010 - 2011 Mercedes-Benz ML450, 2010 - 2011 Mercedes-Benz SLK200, 2009 - 2012 Mercedes-Benz GLK350, 2009 - 2011 Mercedes-Benz SLK300, 2009 - 2009 Mercedes-Benz GLK280, 2008 - 2012 Mercedes-Benz C300, 2007 - 2009 Mercedes-Benz CLK280, 2007 - 2009 Mercedes-Benz E280, 2006 - 2011 Mercedes-Benz C350, 2006 - 2011 Mercedes-Benz E350, 2006 - 2011 Mercedes-Benz ML350, 2006 - 2011 Mercedes-Benz R350, 2006 - 2009 Mercedes-Benz C230, 2006 - 2009 Mercedes-Benz C280
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Item LocatedCanada
ColorNatural
ConditionNew
item #1003CZ4X
Note
This part comes with a cover and thermostat.
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Engine Coolant Thermostat Housing Assembly for Ford Focus Lincoln Mazda Mercury
A-Premium®Part # APTHA0082
Engine Coolant Thermostat Housing Assembly for Ford Focus Lincoln Mazda Mercury
52 Reviews
CA$27.99
Enter ZIP codeFree standard shipping
2-year warranty
90 days free return
Fits 2014 - 2022 Ford Transit Connect, 2012 - 2017 Mazda 5, 2011 - 2012 Lincoln MKZ, 2010 - 2020 Ford Fusion, 2010 - 2013 Mazda 3, 2010 - 2013 Mazda 3 Sport, 2010 - 2012 Mazda CX-7, 2010 - 2011 Mercury Milan, 2009 - 2019 Ford Escape, 2009 - 2013 Mazda 6, 2009 - 2011 Mazda Tribute, 2009 - 2011 Mercury Mariner, 2008 - 2008 Mazda Tribute, 2007 - 2013 Mazda 3, 2007 - 2012 Mazda CX-7, 2007 - 2011 Ford Ranger, 2006 - 2010 Ford Fusion, 2006 - 2009 Mercury Milan, 2006 - 2008 Mercury Mariner, 2006 - 2006 Mazda MX-5 Miata
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Item LocatedCanada
ColorBlack
ConditionNew
item #1005DVVG
Note
Engine Coolant Thermostat Housing Assembly -- Cover, Includes Thermostat.
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A-Premium APTHE047 Engine Coolant Thermostat
A-Premium®Part # APTHE047
A-Premium APTHE047 Engine Coolant Thermostat
52 Reviews
CA$26.99
Enter ZIP codeFree standard shipping
2-year warranty
90 days free return
Fits 2015 - 2019 Kia Sedona, 2015 - 2017 Kia K900, 2015 - 2016 Hyundai Genesis, 2014 - 2019 Hyundai Santa Fe XL, 2014 - 2018 Kia Sorento, 2014 - 2016 Kia Cadenza, 2013 - 2018 Hyundai Santa Fe, 2012 - 2017 Hyundai Azera, 2012 - 2014 Hyundai Genesis, 2012 - 2013 Hyundai Equus, 2011 - 2011 Hyundai Equus, 2010 - 2012 Hyundai Genesis
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Item LocatedUnited States
Quantity1
MaterialMetal and Rubber
ConditionNew
item #1005V3Q1
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Engine Coolant Thermostat Housing Assembly for Jeep Grand Cherokee Dodge Durango
A-Premium®Part # APTHA0310
Engine Coolant Thermostat Housing Assembly for Jeep Grand Cherokee Dodge Durango
52 Reviews
CA$44.99
Enter ZIP codeFree standard shipping
2-year warranty
90 days free return
Fits 2018 - 2018 Jeep Wrangler JK, 2012 - 2017 Jeep Wrangler, 2011 - 2015 Dodge Durango, 2011 - 2015 Jeep Grand Cherokee
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Item LocatedUnited States
Quantity1
ColorBlack
ConditionNew
item #1015HS2V
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A-Premium APTHE043 Engine Coolant Thermostat
A-Premium®Part # APTHE043
A-Premium APTHE043 Engine Coolant Thermostat
52 Reviews
CA$25.99
Enter ZIP codeFree standard shipping
2-year warranty
90 days free return
Fits 2019 - 2019 Mazda CX-5, 2018 - 2018 Mazda 3, 2018 - 2018 Mazda 3, 2018 - 2018 Mazda 3 Sport, 2018 - 2018 Mazda 3 Sport, 2018 - 2018 Mazda 6, 2017 - 2017 Mazda 3, 2017 - 2017 Mazda 3, 2014 - 2017 Mazda 6, 2014 - 2016 Mazda 3, 2014 - 2016 Mazda 3, 2014 - 2016 Mazda 3 Sport, 2014 - 2016 Mazda 3 Sport, 2014 - 2016 Mazda CX-5, 2013 - 2016 Mazda CX-5, 2012 - 2013 Mazda 3, 2011 - 2014 Mazda 2, 2011 - 2011 Mazda 3 Sport, 2004 - 2004 Chevrolet Tracker, 2002 - 2003 Mazda Protege5
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Item LocatedUnited States
Quantity1
MaterialMetal and Rubber
ConditionNew
item #1005V2S4
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Thermostat Housing Assembly for Chevrolet Silverado 1500 1999-2003 GMC Cadillac
A-Premium®Part # APTHA0129
Thermostat Housing Assembly for Chevrolet Silverado 1500 1999-2003 GMC Cadillac
52 Reviews
CA$30.99
Enter ZIP codeFree standard shipping
2-year warranty
90 days free return
Fits 2003 - 2003 Cadillac Escalade ESV, 2003 - 2003 Chevrolet Express 1500, 2003 - 2003 Chevrolet Express 2500, 2003 - 2003 Chevrolet Express 2500, 2003 - 2003 Chevrolet Express 2500, 2003 - 2003 Chevrolet Express 3500, 2003 - 2003 Chevrolet Express 3500, 2003 - 2003 Chevrolet Express 3500, 2003 - 2003 Chevrolet Silverado 1500, 2003 - 2003 Chevrolet SSR, 2003 - 2003 Chevrolet Trailblazer EXT, 2003 - 2003 Chevrolet W3500 Tiltmaster, 2003 - 2003 Chevrolet W4500 Tiltmaster, 2003 - 2003 GMC Envoy XL, 2003 - 2003 GMC Savana 1500, 2003 - 2003 GMC Savana 2500, 2003 - 2003 GMC Savana 2500, 2003 - 2003 GMC Savana 2500, 2003 - 2003 GMC Savana 3500, 2003 - 2003 GMC Savana 3500
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Item LocatedCanada
Quantity1
MaterialAluminum
ConditionNew
item #10027QWE
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Engine Coolant Thermostat Housing Assembly for Audi A8 Quattro RS5 S5 4.2L 105℃
A-Premium®Part # APTHA0329
Engine Coolant Thermostat Housing Assembly for Audi A8 Quattro RS5 S5 4.2L 105℃
52 Reviews
CA$78.99
Enter ZIP codeFree standard shipping
2-year warranty
90 days free return
Fits 2013 - 2015 Audi RS5, 2011 - 2012 Audi A8 Quattro, 2008 - 2012 Audi S5
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Item LocatedUnited States
Quantity1
ConditionNew
item #10177CW2
Note
【Note-1】 Start to Open Temperature: 105℃.
【Note-2】 This item comes with Thermostat.
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Engine Coolant Thermostat for Subaru Outback 00-15 Forester Impreza Legacy 82℃
A-Premium®Part # APTHE076
Engine Coolant Thermostat for Subaru Outback 00-15 Forester Impreza Legacy 82℃
52 Reviews
CA$42.99
Enter ZIP codeFree standard shipping
2-year warranty
90 days free return
Fits 2014 - 2016 Subaru Forester, 2011 - 2013 Subaru Forester, 2010 - 2015 Subaru Legacy, 2010 - 2015 Subaru Outback, 2008 - 2014 Subaru Tribeca, 2008 - 2009 Subaru Legacy, 2006 - 2009 Subaru Outback, 2006 - 2007 Subaru B9 Tribeca, 2005 - 2009 Subaru Legacy, 2005 - 2006 Saab 9-2X, 2004 - 2011 Subaru Impreza, 2004 - 2010 Subaru Forester, 2003 - 2006 Subaru Baja, 2002 - 2005 Subaru Impreza, 2001 - 2005 Subaru Outback, 2000 - 2009 Subaru Outback, 1998 - 2003 Subaru Impreza, 1996 - 2004 Subaru Legacy, 1995 - 2001 Subaru Impreza, 1995 - 1999 Subaru Legacy
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Item LocatedUnited States
Quantity1
ConditionNew
item #1013DYCR
Note
【Note-1】 Start to Open Temperature: 82℃.;
【Note-2】 2014-2016 Subaru Forester H4 2.5L with Manual Transmission or Automatic CVT Transmission.;
【Note-3】 2005 Subaru Outback H6 3.0L with model built before 05/2005.
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Engine Coolant Thermostat for Subaru Outback Forester Impreza Legacy Tribeca 77℃
A-Premium®Part # APTHE074
Engine Coolant Thermostat for Subaru Outback Forester Impreza Legacy Tribeca 77℃
52 Reviews
CA$23.99
Enter ZIP codeFree standard shipping
2-year warranty
90 days free return
Fits 2019 - 2019 Subaru Outback, 2017 - 2017 Subaru Outback, 2015 - 2019 Subaru Legacy, 2015 - 2016 Subaru Outback, 2013 - 2021 Subaru WRX STI, 2013 - 2016 Subaru WRX, 2010 - 2013 Subaru Legacy, 2010 - 2013 Subaru Outback, 2010 - 2012 Subaru Legacy, 2008 - 2013 Subaru Tribeca, 2008 - 2011 Subaru Impreza, 2008 - 2009 Subaru Legacy, 2008 - 2009 Subaru Legacy, 2006 - 2007 Subaru B9 Tribeca, 2003 - 2006 Subaru Baja, 2002 - 2005 Subaru Impreza, 2001 - 2009 Subaru Outback, 2000 - 2012 Subaru Outback, 1998 - 2014 Subaru Impreza, 1998 - 2013 Subaru Forester
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Item LocatedUnited States
Quantity1
ConditionNew
item #1013DW8U
Note
【Note-1】 Start to Open Temperature: 77℃.
【Note-2】 2010-2012 Subaru Legacy H4 2.5L fit Naturally Aspirated only, NOT fit Turbocharged.
【Note-3】 2017 Subaru Outback H6 3.6L fit 3.6R Touring Model only, NOT fit 3.6R Limited or 3.6R Premium.
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Page 2 of 16

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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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