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Mahle B31861 Engine Coolant Thermostat Housing GasketOE Quality 60-Day Returns
Part #: B31861

Mahle B31861 Engine Coolant Thermostat Housing Gasket

116 vehicles fit this part
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Fitment: Ford, Lincoln, Mazda, and Mercury, Fusion, Police Responder Hybrid, SSV Plug-In Hybrid, MKZ, C-Max, Focus, Transit Connect, 3, 3 Sport, MX-5 Miata, Escape, Ranger, Mariner, Milan, B2300, Tribute, 5, and 6
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Not what you need? See all Engine Coolant Thermostat Housing Gasket options

Engine Coolant Thermostat Housing Gasket

Mahle B31861 is an OEM-standard engine coolant thermostat housing gasket built with rubber coated metal for a reliable seal at the thermostat housing. It is made for Ford, Mazda, Lincoln, and Mercury applications across a wide range of 2001-2020 vehicles, including Ford Fusion, Mazda 3, and Ford Ranger platforms.

Mahle gaskets are trusted by OEMs and technicians for consistent sealing performance. This Mahle B31861 gasket includes water outlet gasket content and uses a rubber coated embossed metal construction to help maintain a secure seal in cooling system service.

Key Features

  • Rubber coated metal construction for sealing durability
  • Rubber coated embossed metal gasket material
  • OEM standard item grade
  • Mounting hole quantity: 4
  • Additional package contents: contains water outlet gasket
  • Direct-fit style for thermostat housing sealing service

Detailed Description

Mahle B31861 is an engine coolant thermostat housing gasket engineered for cooling system sealing at the thermostat housing and related water outlet connection points. The rubber coated embossed metal design helps create a stable seal against coolant leaks while supporting OE-style fitment on select Ford, Mazda, Lincoln, and Mercury vehicles. This part number is commonly searched for thermostat housing gasket replacement on Ford Fusion, Mazda 3, and Ford Ranger applications, as well as other listed models.

This part cross-references FEL-PRO 35771 for the same application.

What It Helps Fix

  • Coolant seepage at the thermostat housing
  • Leakage at the water outlet sealing surface
  • Sealing issues after thermostat housing service
  • Coolant odor or visible residue around the housing
  • Loss of seal integrity from aged or compressed gasket material

Installation Notes and Tips

  • Clean the mating surfaces thoroughly before installation.
  • Inspect the thermostat housing and water outlet for warping, corrosion, or damage.
  • Replace the gasket during thermostat housing service to restore sealing performance.
  • Verify vehicle-specific fitment by year, make, and model before installation.
  • Follow the manufacturer service procedure and coolant refill steps for the vehicle.

Quality Assurance

Mahle manufactures sealing products used by OEMs and professional technicians worldwide. B31861 is built to OEM-standard expectations for cooling system sealing and is backed by Mahle’s reputation for application-specific gasket engineering.

BrandMahle
Part NumberB31861
Additional Package ContentsContains Water Outlet Gasket
Gasket MaterialRubber Coated Embossed Metal
Item GradeOEM Standard
MaterialRubber Coated Metal
Mounting Hole Quantity4

This part fits 116 vehicles. Search below:

YearMakeModelLitersCylindersPositionNotes
2020FordFusion2.0LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2020FordSSV Plug-In Hybrid2.0LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2020LincolnMKZ2.0LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2019FordFusion2.0LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2019FordSSV Plug-In Hybrid2.0LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2019LincolnMKZ2.0LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2018FordC-Max2.0LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2018FordFusion2.0LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2018LincolnMKZ2.0LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2017FordC-Max2.0LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2017FordFusion2.0LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2017LincolnMKZ2.0LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2016FordC-Max2.0LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2016FordFusion2.0LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2016LincolnMKZ2.0LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2015FordC-Max2.0LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2015FordFusion2.0LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2015LincolnMKZ2.0LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2014FordC-Max2.0LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2014FordFusion2.0LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2014LincolnMKZ2.0LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2013FordC-Max2.0LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2013FordFocus2.0LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2013FordFusion2.0LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2013FordTransit Connect2.0LL4N/ARubber Coated Embossed Metal; with Metal Housing
2013LincolnMKZ2.0LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2013Mazda32.0LL4N/ARubber Coated Embossed Metal; Thermostat Housing to Head
2013Mazda3 Sport2.0LL4N/ARubber Coated Embossed Metal; Thermostat Housing to Head
2013MazdaMX-5 Miata2.0LL4N/ARubber Coated Embossed Metal; Thermostat Housing To Head
2012FordEscape2.5LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2012FordFocus2.0LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2012FordFusion2.5LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2012FordTransit Connect2.0LL4N/ARubber Coated Embossed Metal; with Metal Housing
2012LincolnMKZ2.5LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2012Mazda32.0LL4N/ARubber Coated Embossed Metal; Thermostat Housing to Head
2012Mazda3 Sport2.0LL4N/ARubber Coated Embossed Metal; Thermostat Housing to Head
2012MazdaMX-5 Miata2.0LL4N/ARubber Coated Embossed Metal; Thermostat Housing To Head
2011FordEscape2.5LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2011FordFusion2.5LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2011FordRanger2.3LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2011FordTransit Connect2.0LL4N/ARubber Coated Embossed Metal; with Metal Housing
2011LincolnMKZ2.5LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2011Mazda32.0LL4N/ARubber Coated Embossed Metal; Thermostat Housing to Head
2011Mazda3 Sport2.0LL4N/ARubber Coated Embossed Metal; Thermostat Housing to Head
2011MazdaMX-5 Miata2.0LL4N/ARubber Coated Embossed Metal; Thermostat Housing To Head
2011MercuryMariner2.5LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2011MercuryMilan2.5LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2010FordEscape2.5LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2010FordFusion2.5LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2010FordRanger2.3LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2010FordTransit Connect2.0LL4N/ARubber Coated Embossed Metal; with Metal Housing
2010Mazda32.0LL4N/ARubber Coated Embossed Metal; Thermostat Housing to Head
2010Mazda3 Sport2.0LL4N/ARubber Coated Embossed Metal; Thermostat Housing to Head
2010MazdaB23002.3LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2010MazdaMX-5 Miata2.0LL4N/ARubber Coated Embossed Metal; Thermostat Housing To Head
2010MazdaTribute2.5LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2010MercuryMariner2.5LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2010MercuryMilan2.5LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2009FordEscape2.5LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2009FordRanger2.3LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2009Mazda32.3LL4N/ARubber Coated Embossed Metal; Thermostat Housing to Head
2009Mazda32.0LL4N/ARubber Coated Embossed Metal; Thermostat Housing to Head
2009Mazda3 Sport2.0LL4N/ARubber Coated Embossed Metal; Thermostat Housing to Head
2009Mazda52.3LL4N/ARubber Coated Embossed Metal; Thermostat Housing To Head
2009MazdaB23002.3LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2009MazdaMX-5 Miata2.0LL4N/ARubber Coated Embossed Metal; Thermostat Housing To Head
2009MazdaTribute2.5LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2009MercuryMariner2.5LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2008FordRanger2.3LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2008Mazda32.3LL4N/ARubber Coated Embossed Metal; Thermostat Housing to Head
2008Mazda32.0LL4N/ARubber Coated Embossed Metal; Thermostat Housing to Head
2008Mazda52.3LL4N/ARubber Coated Embossed Metal; Thermostat Housing To Head
2008Mazda62.3LL4N/ARubber Coated Embossed Metal; Housing To Head; Rear
2008MazdaB23002.3LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2008MazdaMX-5 Miata2.0LL4N/ARubber Coated Embossed Metal; Thermostat Housing To Head
2008MazdaTribute2.3LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2007FordRanger2.3LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2007Mazda32.3LL4N/ARubber Coated Embossed Metal; Thermostat Housing to Head
2007Mazda32.0LL4N/ARubber Coated Embossed Metal; Thermostat Housing to Head
2007Mazda52.3LL4N/ARubber Coated Embossed Metal; Thermostat Housing To Head
2007Mazda62.3LL4N/ARubber Coated Embossed Metal; Housing To Head; Rear
2007MazdaB23002.3LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2007MazdaMX-5 Miata2.0LL4N/ARubber Coated Embossed Metal; Thermostat Housing To Head
2006FordEscape2.3LL4N/ARubber Coated Embossed Metal; Thru 5/1/06
2006FordFocus2.3LL4N/ARubber Coated Embossed Metal; Thru 12/4/06
2006FordFocus2.0LL4N/ARubber Coated Embossed Metal; Thru 12/4/06
2006FordRanger2.3LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2006Mazda32.3LL4N/ARubber Coated Embossed Metal; Thermostat Housing to Head
2006Mazda32.0LL4N/ARubber Coated Embossed Metal; Thermostat Housing to Head
2006Mazda52.3LL4N/ARubber Coated Embossed Metal; Thermostat Housing To Head
2006Mazda62.3LL4N/ARubber Coated Embossed Metal; Housing To Head; Rear
2006MazdaB23002.3LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2006MazdaMX-5 Miata2.0LL4N/ARubber Coated Embossed Metal; Thermostat Housing To Head
2006MazdaTribute2.3LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2006MercuryMariner2.3LL4N/ARubber Coated Embossed Metal; Thru 5/1/06
2005FordEscape2.3LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2005FordFocus2.3LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2005FordFocus2.0LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2005FordRanger2.3LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2005Mazda62.3LL4N/ARubber Coated Embossed Metal; Housing To Head; Rear
2005MazdaB23002.3LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2005MazdaTribute2.3LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2005MercuryMariner2.3LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2004FordFocus2.3LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2004FordRanger2.3LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2004Mazda32.3LL4N/ARubber Coated Embossed Metal; Housing To Head; Rear
2004Mazda62.3LL4N/ARubber Coated Embossed Metal; Housing To Head; Rear
2004MazdaB23002.3LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2003FordFocus2.3LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2003FordRanger2.3LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2003Mazda62.3LL4N/ARubber Coated Embossed Metal; Housing To Head; Rear
2003MazdaB23002.3LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2002FordRanger2.3LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2002MazdaB23002.3LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2001FordRanger2.3LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.
2001MazdaB23002.3LL4N/ARubber-coated embossed metal Engine Oil Filter Adapter Gasket.

* Always verify fitment with your vehicle's VIN if unsure. Submodel & trim restrictions may apply.

This part directly replaces or is cross-referenced with the following part numbers:

35771

Cross-reference numbers are provided for identification purposes only. Always confirm fitment before ordering.