2020 Acura MDX Engine Problems

On XXX, while operating my vehicle, the engine suffered a catastrophic internal mechanical failure due to a broken connecting rod, rendering the vehicle completely disabled and creating a sudden loss of motive power. This vehicle is a 2020 Acura MDX Tech SH-AWD with a 3.5L V6 engine (Engine Code J35Y5). The failure mode experienced is identical to the crankshaft and connecting rod bearing defect detailed in Acura Recall 23V-751 (NHTSA Campaign Number: 23V751000). However, when checking my specific VIN ([XXX]) on the NHTSA lookup tool, it reports 0 unrepaired recalls. My vehicle was excluded from the original recall population despite carrying the exact same engine type, manufacturing year, and experiencing the exact same catastrophic rod fracture resulting from bearing seizure. Because of this severe mechanical failure, the vehicle is un-driveable and requires a complete engine replacement. I am filing this complaint to document that the vehicle population in Recall 23V-751 was too narrowly defined, and to ensure this vehicle is counted in the ongoing NHTSA investigation regarding un-recalled Honda/Acura V6 engine failures. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ID

11776364

Incident

Oct 13, 2026

While stopped at a stop light the auto restart feature engaged and shut the engine off. When the light turned green and I released the brake pedal the engine did not restart and the battery warning light illuminated. As cars were honking I activated my hazards, had to place the car in park and shut off/restart the vehicle. Luckily it restarted and I was able to proceed home. It activated again while stopped to get mail at mailbox and restarted with no issue. Mileage is 42668. Recall 23-001 PGMfi performed 8/2023. Battery replaced 12/2024.

NHTSA ID

11773527

Incident

Oct 25, 2026

My 2020 Acura MDX fails to restart after the Auto Idle Stop system shuts off the engine at stops. The vehicle stalls and will not restart in active traffic, including busy intersections and high-speed roads. This began about three years ago and now happens every day, leaving my family stranded in live traffic lanes at risk of a collision. On [XXX], the engine shut off and would not restart in the middle of the [XXX], with traffic moving around me at about 40 mph. Capitol Acura in San Jose diagnosed a failing starter motor and ordered a replacement under repair order [XXX]. The part has been on backorder since, with no delivery date. I escalated to American Honda / Acura Client Relations on October 13, 2026 (case [XXX]). On [XXX], Acura replied only that it is "still reviewing" my request. No loaner or alternate vehicle has been provided, and no repair timeline has been given. I am concerned this is a defect affecting other MDX owners: a starter that fails under frequent Auto Idle Stop cycling, combined with a parts shortage that leaves unsafe vehicles on the road. I request that NHTSA review this issue for a possible investigation or recall. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ID

11772865

Incident

Oct 19, 2026

The contact owns a 2020 Acura MDX. The contact stated that the vehicle was previously repaired under Technical Service Bulletins: 22-009, 22-024, and 23-002; however, the failure persisted following the repairs. The contact stated that while stopped at an intersection, the engine failed to restart after the Auto Start/Stop feature engaged, and the transmission independently shifted to Neutral (N). The contact shifted the transmission to Park (P) and pressed the Engine Start/Stop button to restart the vehicle. The vehicle was taken to the dealer, where it was determined that the starter required replacement. The dealer requested that the manufacturer replace the starter; however, the request was denied. The contact associated the failure with NHTSA Action Number: EA25004 (Engine and Engine Cooling). The failure mileage was 70,357.

NHTSA ID

11771392

Incident

Dec 1, 2025

Mileage

70,357 mi

Car is not staying on during traffic. Afraid to go in highway now.

NHTSA ID

11770081

Incident

Oct 6, 2026

On multiple occasions while my car is stopped at a light or stop sign the idle restart stalls and the car shuts off. I need to give it a few minutes and restart the car. It mainly happens when the auto shut off for idling restarts. I have had it happen more than 10X with my kids in the car. I have done all required work - timing belt & water pump replacement, transmission fluid flush, new times and new suspension. It continues to get worse.

NHTSA ID

11768242

Incident

Sep 28, 2026

The contact owns a 2020 Acura MDX. The contact stated that while idling and driving on several occasions at various speeds, there was an abnormal knocking sound coming from the engine compartment. The vehicle was taken to an independent mechanic to be diagnosed. The mechanic determined that there was internal engine rod bearing failure, and that the engine needed to be replaced. The contact believed that the failure was associated with Manufacturer Recall Number: 24-001. The manufacturer was notified of the failure. The failure mileage was 65,128.

NHTSA ID

11763569

Incident

Sep 4, 2026

Mileage

65,128 mi

The contact owns a 2020 Acura MDX. The contact stated that while operating the vehicle, the oil light illuminated. The contact stated that after restarting the vehicle, while driving, the vehicle failed to properly accelerate, with a ticking and knocking sound coming from the engine compartment. The vehicle was later towed to the local dealer to be diagnosed and metal shavings from the engine bearings were found in the engine oil. The contact was informed that the engine needed to be replaced. The vehicle was not yet repaired. The manufacturer was notified of the failure, but no assistance was offered. The contact was informed that the VIN was not included in NHTSA Campaign Number: 23V751000 (ENGINE AND ENGINE COOLING). The contact stated that the vehicle had experienced the failure listed in the recall. The failure mileage was 85,000.

NHTSA ID

11763037

Incident

Sep 3, 2026

Mileage

85,000 mi

Engine seized multiple times. Completely broken now. Online it says many people have these problems.

NHTSA ID

11762319

Incident

Sep 4, 2026

My 2020 Acura MDX has experienced repeated Auto Idle Stop system malfunctions. When the system activates at a stop, the engine shuts off and does not return to normal operation as expected. The incidents are becoming more frequent and create a safety concern when the vehicle is stopped in traffic. This problem has been reported by telephone on multiple prior occasions. The 12-volt battery has also been replaced multiple times because we believed the battery was causing the problem, but the condition has continued.

NHTSA ID

11762152

Incident

Sep 4, 2026

The contact owns a 2020 Acura MDX. The contact stated that while driving approximately 35 MPH, there was an abnormal knocking sound coming from the vehicle before the vehicle stalled. The vehicle failed to restart. The maintenance warning light was illuminated. The contact stated that the failure was associated with NHTSA Campaign Number: 23V751000 (Engine and Engine Cooling). The vehicle was towed to the residence. The local dealer was contacted to schedule an appointment, but the vehicle had not been diagnosed or repaired. The manufacturer was not contacted. The approximate failure mileage was 60,541.

NHTSA ID

11757385

Incident

Aug 15, 2026

Mileage

60,541 mi

The contact owns a 2020 Acura MDX. The contact stated that on six occasions the vehicle stalled and failed to restart immediately. The contact stated that while the idle button was on, the failure occurred. The contact was concerned about being in a crash. The vehicle was taken to the local dealer, where it was diagnosed, and two batteries were replaced, and a software update was performed. The dealer would be checking the software to be sure that it was operating as intended. The manufacturer was contacted, and a case was opened. The manufacturer provided a refund for the battery. The failure mileage was approximately 48,300.

NHTSA ID

11757014

Incident

Jan 1, 2024

Mileage

48,300 mi

Engine turns off while in drive or stopped at a red light/stop sign. It has happened 7-10 times withing the last couple of months, but 3-4 times within the last week. Out of the four times it happened, my family's safety was at risk, because the car was in drive, and could've caused us to get into an accident. During the other occasions, we were moving in reverse and stopped at a stop sign. Complaint was made with Acura of Bay Shore in Long Island, NY, at which time an update of computer engine was performed but issue wasn't fixed due to back-order part that needs to be replaced. Unfortunately, just yesterday (August 13, 2026) car turned off at light causing a road hazard to vehicles and my family stuck in a large intersection. Multiple engine lights turned on, but I was unable to turn the car on or move it. approximately 10 min later, I was able to turn the car on and move it to safe location. I spoke to Acura of Bay Shore, and it is a known issue but till this date, isn't fixed. Vehicle is a hazard and can cause serious bodily harm/or death. thank you

NHTSA ID

11756994

Incident

Aug 13, 2026

See attached document for complaint.

NHTSA ID

11747720

Incident

May 14, 2026

The contact owns a 2020 Acura MDX. The contact stated that while driving approximately 20 - 25 MPH, there was an abnormal knocking sound coming from the passenger’s side of the vehicle. The contact stated that the check engine warning light and other unknown warning lights were illuminated. The vehicle stalled and was towed to dealer to be diagnosed. The dealer determined that the engine had seized. The contact associated the failure with NHTSA Campaign Number: 23V751000 (Engine and Engine Cooling); however, the VIN was not included. The manufacturer was made aware of the failure. The failure mileage was approximately 104,000.

NHTSA ID

11746661

Incident

May 9, 2026

Mileage

104,000 mi

While driving my 2020 Acura MDX, the vehicle developed an intermittent check engine light and a noticeable engine knocking noise coming from the engine compartment. The vehicle was taken to an Acura dealership for diagnosis. According to the certified Acura technician, no diagnostic trouble codes were found stored in the vehicle’s system. However, the technician confirmed there was an audible knocking noise present from the engine during inspection. The technician stated "No engine oil leaks found at this time. Engine. I did verify the noise that you are talking about far as knocking noise goes. Right now, it sounds like it's a lower end noise, possibly crank shaft related. Engine teardown would need to be in place to verify which cylinders are bad and to confirm if the bearing is gone or not.". The vehicle has all service records, including routine oil changes at recommended intervals. The technician also confirmed that the vehicle had oil in it. The vehicle is not part of the existing recall, but the symptoms and description match the known crank shaft rod bearing issue.

NHTSA ID

11737478

Incident

May 10, 2026

Interstate driving 70mph. Sudden engine power loss, vehicle slowed to 50mph. Check engine light came on. Engine knocking noises. Drove car 2 miles to our Acura dealership. Service dept says we have rod bearing failure. Currently deciding how to proceed...used or Reman motor repalcement.

NHTSA ID

11734327

Incident

Apr 24, 2026

On March 3, 2026 my son was driving our 2020 Acura MDX when we lost power in the middle of an intersection. The following day we had it towed to Montanto Acura in [XXX] where we were told we had a blown engine due to a bad crank shaft and possibly engine bearings. Prior to this the car drove fine with no warning signs. My son who was [XXX] old was at a dangerous intersection and had to wait for help to arrive to move the vehicle out of the intersection. We had to pay to replace the engine a total of $8,747.36 for a used engine. Now fearing for our son's safety we decided to sell the car at a loss and buy him something we can reply on and that won't put him in danger. Although Acura has recalled many engines, our VIN did not come up in that recall, however we have now been affected by the same issue many others had the recall performed on. I have all service records from our dealership to prove the condition. It is unacceptable that a Honda Engine would fail with 105,374 miles and all service work done at the dealership. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ID

11729475

Incident

Mar 3, 2026

The motor through a misfire code and began making a noise while vehicle was sitting at a red light. Vehicle lost all power and had to be towed. Was quoted my the Acura dealership $9k. Main reason for addressing this concern is because numerous Acura J35 series motors have already been recalled for engine connecting rod issues. While this motor doesn't apparently fall under that recall, odd that it would essentially had the same issue, when it only had 136k miles and has been maintained to factory standards (or better)

NHTSA ID

11728187

Incident

Mar 2, 2026

MY car has 39200. Miles acura mdx 2020 tech package. Has a rod knocking sound. There was a recall number 23v751000 that i was never notified about. I cant drive car under this vondition may harm engine further. Question is this recall still valid even if I was mot informed or does my cars acura/Honda warranty covers repairs or replacement

NHTSA ID

11727655

Incident

Mar 27, 2026

While driving my 2020 Acura MDX A-Spec at approximately 63,744 miles, the vehicle suddenly lost all engine power without warning while passing through a busy multi-lane intersection. The loss of propulsion prevented acceleration and forced us to coast across traffic lanes to reach the shoulder, creating a significant safety hazard. The engine would not restart. The vehicle was inspected on 3/17/2026 by Lyle Pearson Acura (Boise, ID). The dealership diagnosed catastrophic internal engine failure with the following findings: spun rod bearing in cylinder #6, excessive metal debris in the oil pan, and bearing seizure to the crankshaft. The technician stated the failure pattern is consistent with the rod-bearing defect described in Acura Safety Recall / Service Bulletin 24-001. Although my VIN is NOT currently included in the recall population, the confirmed failure mode matches the known defect. This suggests the issue may extend beyond currently identified vehicles that are included in Acura Service Bulletin 24-001 and NHTSA recall 23V-751. The vehicle has a salvage title from prior cosmetic damage only; no engine, drivetrain, or structural components were affected. The vehicle has been properly maintained with documented service history. This failure represents a serious safety risk due to sudden loss of power in active traffic conditions, increasing the risk of collision or injury. I request NHTSA review this incident to determine whether additional vehicles should be included in the recall and to assess the broader safety risk.

NHTSA ID

11725507

Incident

Mar 13, 2026

The contact owns a 2020 Acura MDX. The contact stated that while driving 55 MPH, the accelerator pedal was depressed; however, the vehicle failed to accelerate as intended. The vehicle shook abnormally with the check engine warning light illuminated. Additionally, there was an abnormal sound coming from the engine compartment. The vehicle was driven to the residence. The contact stated that while parking the vehicle, the engine seized. The vehicle was towed to the dealer, where it was diagnosed with rod bearing failure and a failure in cylinder #6. The contact was informed there were metal shavings inside the oil pan, and that the engine needed to be replaced. The vehicle was not repaired. The contact referenced an unknown recall; however, the VIN was not associated with the recall. The manufacturer was made aware of the failure but provided no assistance. The failure mileage was approximately 86,743.

NHTSA ID

11724665

Incident

Feb 22, 2026

Mileage

86,743 mi

During the summer of 2025, the auto idle engine railed to restart while at a stop light. We had to shut off and restart the car. We took it to the car dealer and they did some sort of software update. It happened again in January 2026 while at a stop light off a highway exit ramp. We took it to a different dealer because we were living in a different city at the time. In their computer system, they could see the repair that had been done. They did some sort of other update and submitted it as a warranty repair for Acura (which the other dealer had not done). They noted there was one other repair that could be done, but Acura would not allow them to do both at once and this update usually fixed it. However, it happened again in February 2026. The engine did not restart from auto idle, this time at a stop light toward the beginning of an eight hour road trip back home. Fortunately, turning off the engine and starting it back up worked. We took it back to the second dealer and they did the additional repair authorized by Acura and submitted as a warranty repair. Three incidents of the auto-idle not restarting the engine in less than a year is not acceptable. The car is unrealiable.

NHTSA ID

11722797

Incident

Feb 23, 2026

On December 4th I noticed a rattling sound when I was driving. It worsened when my car would rev above 2RPMs and before shifting. It also would make a terrible grinding sound when I started the car. I had about 1/4 of a tank of gas and thought that maybe that was part of the issue. After filling up, the sound was not as loud, but was still present when I started the car and upon accelerating. I took my car to my Acura dealership on December 5th. Within an hour of having the car they called to tell me that the engine needed to be replaced due to a connecting rod failure. They told me that the car is no longer safe to drive and that the repairs would be required in order to continue to use the vehicle safely. There was no warning sign. My only other concern is that the downshifters of this vehicle have never worked properly. I have mentioned this to the dealership multiple times and even drove the vehicle with their representative to recreate the issue. The car would accelerate and lurch forward upon utilizing the downshift feature. This would also cause the vehicle to over-rev which I am concerned was problematic to the connecting rod failure. Additionally, the vehicle has always made a grinding noise upon starting the engine, but the dealership assured me this was normal. Acura is unwilling to cover the full cost of replacement even though this vehicle has been maintained per the manufacturer's recommendations. There are approximately 90,000 miles on this vehicle.

NHTSA ID

11711475

Incident

Dec 4, 2025

Car started to accelerate randomly and 2 seperate occasions while driving, Car started to decelerate / Brake randomly while driving

NHTSA ID

11711358

Incident

Jan 13, 2026