2021 Subaru Forester engine problems

“Component Failed & Inspection Availability: The vehicle suffered a sudden, catastrophic mechanical engine block failure at 74,000 miles. The dealership teardown confirmed a failed/spun lifter bearing and a fractured connecting rod cap, requiring a complete engine replacement. This sudden oil pressure failure/blockage occurred while the engine oil pan was verified completely full. This sudden mechanical failure is directly consistent with severe localized thermal breakdown from a failing Thermo Control Valve (TCV)—a component subject to Subaru Warranty Extension WMM23—or loose factory RTV silicone debris clogging the oil galleries. The failed components, including the engine block, rod cap, and TCV, have been retained by the owner and are fully available for inspection upon request. Safety Risk: The engine failed catastrophically and seized instantaneously while driving at highway speeds, causing a sudden and total loss of motive power. This created an immediate hazard as the vehicle rapidly decelerated in active traffic without warning, blinding drivers behind me and stripping the vehicle of power steering assist. This forced a dangerous maneuver to navigate…”

“I was stopped at a red light. When the light changed to green I put my foot on the gas and the car totally stalled out. There were no lights, fans or radio on just total silence. I tried to restart the car putting it is park and depressing the brake while pushing the start button and nothing. It didn't even try to turn over. silent, dead. I tried several times with no luck. I got out of the car to signal to the bus and row of cars behind me to pass me. I got back into the car and tried to start it again and this time it started. I drove immediately to the mechanic near my house. They couldn't see what was going on without me leaving the car next week. The battery had been replaced 6 months ago. This was a busy intersection and I was worried about getting out of the car but I had no choice.”

“On two separate occasions, less than one year apart after Subaru Service replaced my battery with a “larger” battery without my knowledge my vehicle suffered sudden, catastrophic electrical failure while moving in active highway traffic, causing an immediate loss of propulsion and creating a life-threatening safety hazard. This has happened two times the second time less than a year after the “larger” battery replacement. This car has less than 50,000 miles on it and has a perfect service record all done at AutoNation Subaru Carlsbad. We refuse to drive this car, even though it has been serviced and a new battery has, yet again, been installed. We have no faith in this car and are not willing to put ourselves in a life-threatening situation again. We also do not feel comfortable selling this car, even though we have received many above market offers. We do not feel that we can sell this car in good conscience to an unknowing next victim. It is unsafe to drive and can lose power at any moment while driving without any explanation given from Subaru. The first battery failure occurred prematurely in August 2025. Asked repeatedly why a car battery would fail while…”

“My 2021 Subaru Forester has a recurring, worsening defect in the Idle Stop/Start (ISS) system that creates a stalling hazard. When ISS shuts the engine off at a stop, the engine intermittently fails to restart when I try to move again. It cranks progressively slower, warning lights illuminate, a continuous alert sounds, and the vehicle cannot proceed until I shift to Park and restart manually. This has left me immobile in live traffic at lights, stop signs, and mid-turn. The system also attempts to shut down in unfavorable moments, such as mid-turn, or as I am already releasing the brake (meaning it was depressed only lightly or briefly); it then tries to restart while still mid-shutdown, producing a pronounced shake. This is not a battery-charge problem. It has occurred even when the battery tested above its rated cold-cranking amps, and after each failure the engine restarts smoothly by manual start, indicating the starter, engine, and fuel systems function normally. I raised this before 2024, but it was not recorded until May 2024. At that visit the dealer performed the TCM reprogramming in Service Bulletin 16-147-24 (Forester, auto start/stop engine speed…”

“While driving this car on April 4, 2026 at around 6PM, I experienced the distinct smell of gasoline. I had driven for about 5 minutes on our way to a local restaurant that is approximately an 8 minute drive from our residence. My wife said that she had just filled the gas tank that afternoon. After arriving at the restaurant, I checked the gas cap to ensure it was tightly sealed. I also checked to ensure no fuel was leaking from the car. After finishing dinner, we I drove the car back to my residence and once again, 5 minutes into the drive, I smelled gasoline. After we arrived home, I check the vehicle exterior for leaks and found no liquids under the car. The following day, April 5, 2026 at approximately 1115 AM, having once again found no liquids or gasoline under my car, I drove the car to my local repair shop; an 8 minute drive. About 5 minutes into the drive, I smelled gasoline again. I parked the car at the repair shop, but while adjusting the parking to fit better between the painted lines, I saw and heard a large puff of smoke from the hood area. I immediately put the car into Park, shut off the engine and ran from the car. After exiting, I saw that…”

“While driving the car, the engine stops completely. After a few seconds, it can be restarted. It does this several times a week at random intervals. It's very dangerous since it usually happens when we're driving in traffic. The dealer checked it out in July but couldn't find anything wrong. Even though it's a serious safety problem, they said to keep driving it until it does it every time the car is driven or until the car won't run. When this happens, all the dashboard warning lights come on and the word "Eyesight" is displayed with a diagonal line through it. A warning buzzer also sounds. This started last summer with very infrequent occurrences and is now several times a week.”