Headers Kit for Lincoln Navigator Mark LT & Ford Expedition (2015-2017) 3.5L Ecoboost

Upgraded Headers Kit for 2015-2017 Lincoln, Ford Navigator, Expedition

What it Does: Replaces the structurally deficient factory exhaust manifolds with thicker-walled 304 stainless steel units utilizing all 11 stud locations to prevent thermal warping and exhaust leaks.

The Stock Navigator, Expedition Thermal Weakness

The OEM Ford 3.5L EcoBoost exhaust manifolds suffer from a documented engineering flaw regarding thermal management and clamping force. Although the 3.5L cylinder head features 11 threaded holes for exhaust studs, the factory manifolds are designed to only utilize 8 of these locations. Under heavy load and the high exhaust gas temperatures (EGTs) inherent to turbocharged applications, the unequal thermal expansion causes the thin-walled OEM cast manifolds to warp. This loss of structural integrity leads to shearing of the exhaust studs, blown manifold gaskets, and severe exhaust leaks before the turbos, resulting in poor spool-up and drivability issues.

The Engineering Solution

Doctor Diesel USA addresses this failure point by utilizing all 11 factory stud locations to ensure even clamping pressure across the entire mating surface. The redesigned manifolds are constructed from heavy-duty, thick-walled 304 stainless steel, vastly superior at resisting the thermal deformation caused by sustained high EGTs. Additionally, the internal runner geometry is optimized to improve exhaust flow into the turbos. To further combat heat soak and expansion stress, each kit includes 22 class 8.8 exhaust studs that are 15mm longer than stock, paired with custom exhaust spacers. This mechanical arrangement acts as a thermal buffer, allowing the manifold to expand and contract freely without exerting shear forces on the studs.

Technical Specifications

Compatibility

• 2011-2016 Ford F150 w/ 3.5L Eco-Boost
• 2015-2024 Ford Transit w/ 3.5L Eco-Boost
• 2011-2014 Ford Expedition w/ 3.5L Eco-Boost
• 2011-2014 Lincoln Mark LT w/ 3.5L Eco-Boost
• 2015-2017 Lincoln Navigator w/ 3.5L Eco-Boost

The Ford and Lincoln Durability Standard

Whether towing heavy loads or commuting under strenuous conditions, this comprehensive manifold and stud upgrade restores lost turbo efficiency and ensures reliable, leak-free operation for your EcoBoost under the most demanding driving scenarios.