2004-2011 Mitsubishi Endeavor Problems & Issues

NHTSA campaign 10V065000 covers 2004-2010 Endeavors built January 2003 through March 2010 and operated in road-salt states. Long-term exposure to salt-laden road spray corrodes the fuel filler pipe until it perforates, and fuel leaks from the pipe - most obviously during refueling, when the pump nozzle keeps clicking off or fuel runs onto the ground. A fuel leak near hot exhaust and road ignition sources is a fire risk. This is a geographic recall: cars that have always lived in dry states were not included.

NHTSA campaign 08V454000 covers 2005-2007 Endeavors on which an improperly formed fuel tank mounting bracket can split. In a severe collision with a full fuel tank, a split left rear tank-strap bracket can break and let the tank drop, risking a fuel leak and fire. This is a manufacturing/forming defect in the bracket itself, separate from the later 10V065 filler-pipe corrosion campaign, and it applies regardless of what state the vehicle lives in.

The Endeavor 4-speed automatic transmission develops harsh shifting and premature wear, often failing between 100,000 and 130,000 miles. The transmission shares components with the Galant and Eclipse platforms, inheriting their reliability weaknesses.

A distinct, fluid-driven complaint on the 4-speed automatic, separate from the harsh-shift/failure pattern. Drivers feel a shudder or fine vibration - often described as driving over rumble strips - at a steady throttle around 35-50 mph in 3rd or 4th gear near 1500 rpm, when the torque converter clutch locks up. Mitsubishi documented the same 35-50 mph torque converter shudder from automatic transmission fluid breakdown on other models of the era (TSB-03-23-006, listed for Galant and Mirage rather than the Endeavor), and owners report that filling with a generic ATF rather than the Mitsubishi-specified fluid brings it on or brings it back after a service.

On salt-belt Endeavors the rear crossmember (the subframe carrying the rear suspension) rots at its body mounts until a mount snaps off. Owners report a heavy metallic crunching noise from the rear before discovering a mount rusted through. This is the single most consequential rust failure on the nameplate because the mounts are not weldable to any safe standard and the crossmember is a discontinued part - FWD cars use MR589218 (superseded to 4100A031), AWD cars MR589198 (superseded to 4100A032). Mitsubishi's corrosion recall SR-16-003 covered front crossmember mounts on Lancer and Outlander only; it does not cover the Endeavor and does not cover the rear crossmember on any model.

The 6G75 Endeavor runs three catalysts: a pre-cat integrated at each exhaust manifold plus an unmonitored underfloor unit. Only the two manifold pre-cats are monitored, so a check-engine light for catalyst efficiency always points at a manifold cat, never at the big underfloor converter that most quick-lube shops quote. Owners and techs confirm the mapping on this engine: the right (windshield-side) bank sets P0421 and the left (radiator-side) bank sets P0431. The pre-cats sit right at the head and cook, and they are commonly killed early by an upstream problem - a misfire or leaking injector dumping raw fuel into the converter.

Endeavors left the factory without a cabin air filter - Mitsubishi treated the blower housing filter as an accessory - so leaves, needles, and grit are drawn straight onto the evaporator. That debris, combined with factory gasket material that breaks down over time, packs the evaporator drain until condensate backs up and pours out into the passenger footwell. Owners find a soaked carpet, fogged glass that will not clear, and a persistent musty or sour smell from the vents. Left wet, the carpet and underpad rot and the corrosion reaches body seams and floor-mounted connectors.

On AWD Endeavors the rubber carrier around the driveshaft center support bearing deteriorates and collapses, letting the bearing run dry and out of alignment. Owners describe a belt-squeal or whistle that only shows up after 10-15 minutes of driving once things heat up, rising with RPM rather than road speed, and often mistaken for an accessory belt or the power steering pump. Left alone the bearing seizes and the driveshaft develops a vibration. Because Mitsubishi does not sell the bearing separately for this application, the failure typically forces replacement of the entire propeller shaft.