2018 Acura MDX engine problems

The connecting-rod bearings wear and seize prematurely, directly leading to engine damage. This is the core defect acknowledged in NHTSA Recall 23V-751. Owners report that the bearings fail even under normal driving conditions, and the failure cascades into other engine problems including oil circulation issues, catalyst converter contamination, and eventual complete engine seizure or requiring bottom-end rebuild.

When: Between 40,000 and 130,000 miles; some owners report intermittent symptoms over months or years before catastrophic failure

Symptoms owners cite: Engine hesitation and reduced acceleration; Intermittent stalling at stops or while accelerating; Abnormal engine rattling or knocking sounds; Check engine light illumination; Engine failure or immobilization; Vehicle unable to be restarted after stalling

Codes mentioned: P0159 (O₂ sensor slow response), P0430 (Catalyst Efficiency Below Threshold, Bank 2)

Repairs/costs cited: Owners cite bottom-end rebuilds under warranty and complete engine replacement as repair solutions. One owner reported bottom-end rebuild at 40k miles, same issue recurring at 80k miles. Repair typically requires separating engine from transmission, plus gaskets, seals, and related parts not covered by recall. Oil-pump leaks observed in service notes.

Recalls/TSBs owners mention: NHTSA Recall 23V-751 issued for Engine and Engine Cooling. Acura's repair plan involves connecting-rod bearing inspection/replacement; however, Acura developed a diagnostic tool to assess damage, delaying repairs. Multiple owners report being told parts were unavailable, authorization was pending, or recalls marked as 'completed' after engine failure occurred. One owner reports dealer staff treated them rudely and dismissed repeated recall service requests.

Engine stalls or loses power without warning when owners attempt to accelerate from stops, merge into traffic, or navigate normal driving conditions. Some stalls occur at 5–30 mph. No warning lights precede failure. One owner experienced an abrupt stall during a left turn that resulted in being rear-ended; airbags did not deploy. This symptom appears related to the bearing defect but manifests as a drivability hazard independent of a check-engine light.

When: Throughout vehicle ownership; timing varies by owner. One owner experienced stalling over two years. Mileage ranges from under 50,000 to 130,000+.

Symptoms owners cite: Vehicle stalls while accelerating from a stop; Vehicle stalls at low speeds (5–30 mph); Loss of power when depressing accelerator pedal; Vehicle loses power mid-turn, causing rear-end collision; No warning light illuminated before stall event; Vehicle can be restarted after stalling

Repairs/costs cited: Dealers contacted but unable to diagnose or repair the issue. No repair performed.

Recalls/TSBs owners mention: NHTSA Recall 23V-751. Owners notified; parts unavailable or not scheduled. Dealers unable to replicate symptoms during test drives.

Engine hesitates, jerks, or fails to accelerate as intended when the accelerator pedal is depressed. Some owners report needing to apply additional pressure or depress the pedal to the floorboard to achieve normal acceleration. One owner also reported unintended acceleration at low speeds (5 mph) that self-corrected after several minutes. No warning lights typically accompany these events.

When: Reported across vehicle ownership. One owner notes hesitation issues dating back two years; another reports hesitation at 65,000 miles.

Symptoms owners cite: Engine hesitates when accelerating from a stop; Vehicle jerks or hesitates during acceleration; Reduced acceleration response; Requires extra pressure on accelerator pedal to achieve intended acceleration; Unintended acceleration at low speed that self-corrects; No warning lights illuminated

Repairs/costs cited: Not repaired. One owner reports technician performed an electronic update two years prior that did not resolve the issue.

Recalls/TSBs owners mention: NHTSA Recalls 23V-858000 (Fuel System) and 23V-751000 (Engine and Engine Cooling) cover this vehicle. Owners were notified; however, repair parts were not available at time of complaint.

One owner reports that while the vehicle was parked in a garage, flames and fumes suddenly erupted from the engine compartment. Fire Department extinguished the fire, but the vehicle was consumed. Home and driveway sustained fire damage. Owner's wife experienced emotional distress. This catastrophic failure occurred at 50,000 miles and is consistent with the bearing-related oil circulation and ignition hazards described in the recall notice.

When: At approximately 50,000 miles, while vehicle was parked and unoccupied

Symptoms owners cite: Sudden smoke odor; Fumes and flames from engine compartment; Complete vehicle destruction by fire

Repairs/costs cited: Vehicle destroyed; not repaired.

Recalls/TSBs owners mention: Recall 23V-751 acknowledged oil circulation issues and increased risk of fire. Fire Department and manufacturer were notified.

Across 28 complaints, the dominant theme is that repair parts for Recalls 23V-751 and 23V-858000 have been chronically unavailable, delaying or preventing recall service for over one year in many cases. Owners report being told parts would arrive months away (August, December), dealers are booked out until December after parts arrive, and there is no estimated repair date. Some owners note permanent engine damage may occur during the waiting period while original warranty expires. One owner in Puerto Rico reports no MDX has had the bearing recall repaired by any dealer on the island after 1.5 years. The manufacturer told several owners they had 'exceeded a reasonable amount of time' for the recall repair.

When: From early 2024 through 2025; some owners report waiting over one year since initial recall notification

Symptoms owners cite: No parts available to perform recall repair; Indefinite scheduling delays; Dealers booked out months in advance; No estimated repair completion date; Warranty expiration during wait period; Runaround between dealer and manufacturer regarding parts and authorization

Repairs/costs cited: Repair not performed due to parts availability. One owner reports Acura developing a diagnostic tool, further delaying action.

Recalls/TSBs owners mention: Recalls 23V-751 and 23V-858000 issued; however, Acura has not supplied parts to dealers in timely manner. Owners report being told parts unavailable, authorization pending, or dealers unable to schedule service. Manufacturer confirmed parts unavailable but has not provided replacement vehicle or interim safety solution.