2021 Subaru Ascent Engine Problems

My 2021 Subaru Ascent (40,000 miles) suffered multiple major mechanical failures that pose ongoing safety concerns: 1. Engine Oil Leak: The vehicle developed an active engine oil leak at 20,000 miles, posing a risk of fluid contacting hot exhaust/engine components under the hood or causing low oil levels during operation. Repair time more than 35 days due to parts not available. 2. Loose Factory Engine Mounts: At 25,000 miles, excessive engine shifting, vibration when braking, the dealer discovered loose engine mounts. 3. Transmission Valve Body Failure: At 40,000 miles The transmission Valve Body Failure and need replacement.

NHTSA ID

11753410

Incident

Mar 9, 2024

Oil leaking from upper and lower oil pan. Oil seeping from head gasket and CVT chain pump cover. RTV sealant failure. $4800 to repair. Subaru needs to solve these oil leak issues. Leaking oil is bad for the environment and engine failure could cause accidents and injury.

NHTSA ID

11749720

Incident

Jun 24, 2026

On May 14, 2026, while driving a 2021 Subaru Ascent (approx. 94,291 miles) on a Texas expressway at highway speed during rush hour, I experienced a sudden and significant loss of engine power. There were no warning lights, no safety system activation, and no advance indication of the failure. The vehicle decelerated abruptly with traffic behind it. Live OBD-II data was being logged during the drive and was provided to the service advisor at the authorized Subaru retailer. This incident occurred only 3 days and approximately 125 miles after the vehicle was returned following a major engine repair performed at an authorized Subaru retailer in Texas under active powertrain warranty. That repair was supervised by a Subaru of America District Quality Manager and Field Technical Specialist, who conducted a 110-mile validation drive prior to release. Prior to the highway failure, visible fluid leaks were documented across the intake ducting, residue on lower engine components, a sweet and burning odor after driving, and milky sludge returning to the coolant reservoir — all within 125 miles of pickup. These are consistent with ongoing oil and coolant cross-contamination, which was the original diagnosis documented in the dealership's digital service portal. The vehicle has now undergone three major engine teardowns since March 17, 2026 — over 100 days out of service — for the same underlying powertrain issue on the FA24 engine. The current repair involves cylinder heads sent to a third-party machine shop. Vehicle telematics confirm the vehicle has not been started since May 27, 2026. This report is filed to establish a federal safety record of the highway power loss incident and the recurring nature of this powertrain failure. An active Subaru of America customer advocacy case is on file regarding this vehicle.

NHTSA ID

11746580

Incident

May 14, 2026

While driving my Subaru Ascent, a check engine warning light appeared on the dashboard. Shortly afterward, I noticed smoke coming from the engine compartment. I immediately pulled over and turned the vehicle off. Within moments, flames began coming from under the hood. The fire spread rapidly, and within 5-10 minutes the entire vehicle was fully engulfed in flames. The fire originated from the engine compartment. The vehicle was a total loss. Subaru of America was notified on 12/23/2025, but no follow-up or update on investigation has been responded. The vehicle was always serviced with Subaru. This sudden, traumatizing and catastrophic failure with no prior warning.

NHTSA ID

11712180

Incident

Dec 20, 2025

The transmission on our 2021 Subaru Ascent is slipping and failing to accelerate, RPMs reving, and every issue indicator notification light is on. We took the car to our mechanic, then to the Subaru dealership service dept for diagnosis. A full transmission replacement is required plus associated repairs for a cost of $14,543.98. Service estimate attached. This repair is more than 2/3 of the value of the vehicle. This make/model and transmission type have documented problems and Subaru has previously issued an extended warranty on other model years for this same transmission issue. We are trying to communicate with the Subaru customer service but have had limited response due to the holidays and have not had a resolution yet in the past month.

NHTSA ID

11710776

Incident

Dec 18, 2025

Vehicle smells of fuel inside the cabin and when parked in the garage. To date the dealer is unable to diagnose the problem. 60k miles

NHTSA ID

11707202

Incident

Nov 25, 2025

Oil leak from engine constantly from FRONT DIFFERENTIAL, rec cvt pump reseal with new trans seal, pump is leaking causing drips ; drain plug is also leaking. Need to Replace Front and rear Pads & Rotors at 35k miles which is unheard of. Accessed by suberu dealership.

NHTSA ID

11689564

Incident

Sep 3, 2025

Transmission needed a full replacement

NHTSA ID

11617822

Incident

Sep 2, 2024

The transmission of my 2021 Ascent regularly slips or shutters when trying to accelerate time to time(not always). Loud noises when shifting from low speed. Went to dealership but they said car working perfectly.

NHTSA ID

11515496

Incident

Apr 4, 2023

The contact owns a 2021 Subaru Ascent. The contact stated while driving at 65 MPH, the vehicle shut down completely. A message indicating that the vehicle had unexpectedly stopped, and to check the vehicle as the remote start had failed was displayed. The contact was able to veer to the side of the road safely and waited until the vehicle cooled down. The contact restarted the vehicle and continued driving. The vehicle was taken to the dealer where it was diagnosed that no issues were found. However, the failure reoccurred several times while driving. The vehicle was not repaired. The manufacturer was contacted and informed the contact that they could not assist as the dealer diagnosed that no issues were found. The failure mileage was 300.

NHTSA ID

11488972

Incident

Oct 12, 2021

Mileage

300 mi

I found a lot of oil leaking from the oil filter cup and that would splash all around the filter area. I brought the car at the dealership and they have replaced the filter but when I checked after few days ( smoke was coming out of the hood) there was oil all over again. I bought an aftermarket filter and I installed it myself. No one drop of oil found. So I believe this a is a safety concern because the oil might catch on fire with the heat of the engine. I believe a defective oil filter design or a bad technician training or both are causing the problem.

NHTSA ID

11486441

Incident

Aug 1, 2022

Unknown. I am smelling gasoline in the cabin of the car. A LOT of fumes fill my garage when I start the car. The car sometimes accelerates when I put it in park, resulting in more fumes. Fuel efficiency is lower than expected as well.

NHTSA ID

11442758

Incident

Dec 5, 2021