Product Description
MAHLE C31900 is an OE-quality coolant thermostat housing (coolant outlet) gasket for the 2001–2016 GM 6.6L Duramax (LB7, LLY, LBZ, LMM, LML). Built to meet OEM specifications, it provides a reliable seal between the thermostat housing and the cylinder head to help prevent coolant leaks and overheating.
- Application: 6.6L Duramax LB7/LLY/LBZ/LMM/LML (2001–2016)
- Position: Thermostat housing / coolant outlet to cylinder head
- Material: Steel
- GTIN/UPC: 027067720870
Fitment
- 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016 Chevrolet Silverado/GMC Sierra 2500HD & 3500HD with 6.6L Duramax (LB7, LLY, LBZ, LMM, LML)
Cross Reference Numbers
- GM / ACDelco: 97223686 (Thermostat Housing Gasket)
- Fel-Pro: 35757
- MAHLE: C31900
- GTIN/UPC: 027067720870
What’s Included
(1) Thermostat housing gasket.
FAQ
Will this fit all 2001–2016 Duramax engines?
Yes. It fits LB7, LLY, LBZ, LMM, and LML 6.6L Duramax applications from 2001 through 2016.
How many gaskets do I need?
Typically one per cylinder head location at the thermostat housing; verify your specific repair procedure.
Is this an OEM-equivalent part?
Yes. It’s an OE-quality replacement designed to meet OEM specifications.
Any installation tips?
Clean both sealing surfaces, inspect for damage/warpage, and torque fasteners to OEM spec. Replace thermostats if age/mileage is unknown.
