This bulletin provides updated parts information and a service procedure to follow for removing accumulated carbon deposits from fuel injectors and internal engine components (e.g. intake valves and / or manifold, and combustion chambers). (This is an revised version of the original bulletin.)
full bulletin at NHTSA ↗2021 Subaru Ascent engine problems
moderate Owners of the 2021 Subaru Ascent have filed 5 NHTSA complaints about the engine at roughly $3,100 to repair (U.S. federal records, as of July 2026). Source: NHTSA Office of Defects Investigation. See engine across all vehicles →
Complaints
5
Recalls
0
Avg fix
$3,100
| Model year | engine complaints |
|---|---|
| 2019 Ascent | 21 |
| 2020 Ascent | 10 |
| 2021 Ascent (this page) | 5 |
| 2022 Ascent | 5 |
What stands out
Of the 4 model years of Subaru Ascent we track for engine problems, this one has the fewest owner complaints on file (5).
Is there a fix? Manufacturer service bulletins
The manufacturer has issued service bulletins covering engine on this vehicle — documented repair instructions, service campaigns, or warranty extensions sent to dealers. A TSB isn't a recall (it's not a free safety remedy), but it's the manufacturer acknowledging the issue and how to fix it.
This bulletin provides updated parts information and a service procedure to follow for removing accumulated carbon deposits from fuel injectors and internal engine components (e.g. intake valves and / or manifold, and combustion chambers). (This is an revised version of the original bulletin.)
full bulletin at NHTSA ↗This bulletin outlines the diagnostic and repair procedure for white smoke emitted from the exhaust after startup.
full bulletin at NHTSA ↗This bulletin announces the design change made to the exhaust manifold flange nut material that has been changed from stainless steel to medium carbon steel. This change also necessitates a revised tightening torque specification. (This is an revised version of the original bulletin.)
full bulletin at NHTSA ↗This bulletin provides updated parts information and a service procedure to follow for removing accumulated carbon deposits from fuel injectors and internal engine components (e.g. intake valves and / or manifold, and combustion chambers).
full bulletin at NHTSA ↗Source: NHTSA manufacturer communications. Bring the bulletin number to your dealer or shop.
What owners are reporting 4 most recent
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
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.
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…
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…
Had engine trouble with your 2021 Subaru Ascent?
File a complaint with NHTSA → It's free, official, and how every report above got here — owner filings are the federal safety record this page is built on.
Common questions
How serious is the engine problem on the 2021 Subaru Ascent?
It's a documented issue but not catastrophic. 5 complaints have been filed. Repairs average $3,100 and most owners catch it before it causes a breakdown.
At what mileage does the engine typically fail?
Mileage data is limited for this issue. Owners report failures across a wide range, suggesting cause is more about driving conditions and maintenance than mileage alone.
What does it cost to fix?
Independent shops typically charge around $3,100 for engine repairs on this vehicle. Dealer pricing tends to run 20-40% higher. The exact figure depends on the specific failure mode, parts availability, and your local labor rates. If you're outside factory warranty, an extended service contract often covers this category.
Are there any recalls related to engine?
No active recalls currently cover engine issues on this vehicle. The complaints filed represent owner-reported failures that haven't risen to the level of a manufacturer-issued recall — but they're still worth knowing about before you buy or budget for repairs.
Related
Complaint and recall data sourced from the National Highway Traffic Safety Administration (NHTSA)
public records database. Verify the raw federal record at
nhtsa.gov/vehicle/2021/Subaru/Ascent.
Severity ratings are derived from reported crashes, fires, injuries, and fatalities. Repair cost estimates are
independent-shop national averages and may differ in your area. Some links on this page are affiliate links.