Engine And Engine Cooling Problems of Subaru Forester - part 1

Engine is misfiring, causing in ability to accelerate properly and loads multiple error codes. Upon taking it to the dealership for services, we were told that there is a significant amount of carbon built-up inside the engine. The car has only 6,800 miles on it. The dealership stated that it is an issue that Subaru engineering is aware of but has yet to figure a way to resolve it. The dealership informed us that hybrid engines have had severe carbon build-up on the in-take valves that causes misfiring, loss of power, bucking and stumbling of the engine. Apparently this has been reported all over different on-line forums. The dealer informed us that they would need to order a valve cleaning kit as referenced un service bulletin 02-193-24 and the engine would require walnut blasting. The vehicle was dropped off for service on 7/22 the work was completed, but upon restarting the engine more codes fired up and they stated that the electronic communication module failed and it would now require an escalation to the Subaru engineers called techline, "they now say that the ecm now needs replacement, still misfiring and has become a more complicated issue".

See all problems of the 2025 Subaru Forester 🔎.

I was parking at the dentist office in their parking lot going slow, turned into a parking space and thought I was slowly braking but my car lunged forward and hit a tree. I would normally be minimally braking, so I'm not sure what happened but it was sudden. I could have hit the gas pedal but I would have pressed it a lot I think for the sudden lunge to happen.

See all problems of the 2015 Subaru Forester 🔎.

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 drop on restart) plus an ecm update. A later visit added another ecm update. A dealer has now identified yet another tcm reprogramming, quoted for a fee. The failure has persisted across all of these updates. Dealer staff acknowledge repeated customer complaints with these exact symptoms and say there is no known effective fix. Because iss cannot be permanently disabled through any factory control, I must remember to disable it manually every drive to avoid a restart failure in traffic. The vehicle is available for inspection. This is an ongoing, unresolved safety defect that repeated manufacturer software remedies have failed to correct, and it can leave the vehicle disabled in live traffic.

See all problems of the 2021 Subaru Forester 🔎.

My 2020 Subaru Forester sport suffered catastrophic engine failure on 6/19/2026 at 156,322 miles, 15 days and 1,031 miles after a thermo control valve (tcv) repair performed at an authorized Subaru dealer on 6/4/2026. The tcv is a known defect covered under Subaru TSB 09-119-24 (extended coverage to 150,000 miles/15 years). I never received mailed notification of this TSB and therefore did not seek repair within the covered window; Subaru approved the repair as a goodwill exception. While driving on I-70 westbound near genesee, CO, on a sustained mountain grade with my family in the vehicle, I heard a loud noise. The oil temperature spiked to approximately 280°f, warning lights illuminated, and the vehicle lost all power in highway traffic. Losing propulsion on a steep grade in mountain traffic created a serious risk to my family and surrounding vehicles. Post-failure condition: empty coolant reservoir, coolant-contaminated (milky, green-tinted) oil, and metal debris on the dipstick, consistent with cooling-system failure causing engine seizure. I have timestamped photos. The engine is locked and the vehicle inoperable. The vehicle was towed to the same authorized dealer on 7/9/2026. The dealer's technician confirmed the engine is seized and requires teardown ($3,302. 95) for full diagnosis; the dealer states teardown proceeds only on authorization from me or Subaru of America. I opened a case with Subaru of America on 5/26/2026 and formally requested in writing that Subaru authorize the teardown, with a stated deadline. As of 7/17/2026, the dealer confirms Subaru has sent no authorization or any communication during the week the vehicle has been on their lot. My written deadline, follow-up call, and final written notice went unanswered. The vehicle and all components are preserved at the dealer and available for inspection upon request.

See all problems of the 2020 Subaru Forester 🔎.

My new vehicle, with under 4,000 miles, has already suffered multiple chewed wires due to rodents attracted to the soy-based wire coatings used by the manufacturer. This is not a minor inconvenience — it is a serious safety issue. Damaged wiring can cause loss of power steering mid-drive, abs and braking system malfunctions, airbag deployment failures, engine stalling on highways, and electrical fires — any of which can result in injury or death. The manufacturer knows soy-based coatings attract rodents, the consequences are safety-critical, and proven mitigations exist (capsaicin-infused coatings, hardened sheathing, metal conduit) yet are not implemented from the factory. If vehicles are engineered to withstand foreseeable environmental hazards like water intrusion, heat, and road debris, there is no justification for leaving critical wiring defenseless against a well-documented and predictable threat. A material choice known to invite damage, paired with insufficient physical barriers, is not an external cause — it is a design flaw.

My car is violently shaking and completely stalling out in intersections when attempting to restart from an auto-stop.

I have owned this vehicle since 2019 and the auto start has always stalled out when I stop at a light or stop sign. The vehicle needs to be put in park and restart the car. It is very dangerous.

I was pulling into a parking spot almost stopped when the vehicle suddenly surged forward. I slammed on the brake and put the car in reverse since it had driven upon the walkway. This happened earlier today and I plan to have it checked out as soon as possible . Never have had this problem before, no warning lights or messages.

The air conditioning system of my 2017 Subaru forrester suddenly went out without warning. I noticed a defect when the a/c started buzzing with a high pitched sound and blowing semi-warm air instead of cool. I took my auto to a car repair shop. He provided this diagnostic analysis: normal coolant level in the system. Performed leak detection test- no detectable leak found at this time. A/c system pressures are too high on both pressure ports. A/c compressor has an internal noise. System is clogged. Ventilation interior cabin filter inspected and given a check at 24, 027 miles. Inspected , removed and replaced engine and cabin air filters at 41,600 miles. Inspected and removed and replaced engine and cabin air filters at 56,375. There are no other a/c related inspection or maintenance requirements to be accomplished (reference Subaru forrester maintenance/ automation Subaru arapahoe. My vehicle currently has 64,695 miles. My mechanic is currently working up an estimate for the a/c condenser, clutch, pump replacement. . . Essentially the entire system. I consider this a latent defect and wish to be compensated for the repairs. Due to the weather, I wish to have the repairs accomplished and then be reimbursed. I have read articles on line stating this defect has become commonplace for 2017 and 2018 Subaru forresters. This should be a recall item.

See all problems of the 2018 Subaru Forester 🔎.

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 the car ignited with visible fire under the engine compartment. I called 911 to request fire department help. No damage to any structures or other cars occurred. Q1 above: no the car is totaled and unavailable for inspection as far as I know. Q2 above: I had to run from a burning car. Q3 above: no. Q4 above: yes, the car was inspected by my insurance company, usaa. Q5 above: no, there were no warning lights or any indictor that there was trouble. I would like to note that the car was brought in to my Subaru dealership service station (hyman brothers in midlothian, va) for a heater element safety recall several months ago.

Automatic start/stop fails to turn car on - intermittent. Taken it to Subaru detailer miltiple times and paid for services to correct the issue, but the issue persists. Fist time - replaced the battery in July 2025. 2nd time, went on a ride along for 1 hour, issue did not happen, replaced spark plugs, issue persists. 3rd time, updated tcm software, issue still persists. Subaru of America is aware of the issue and have not gotten a resolution either.

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.

This has now happened twice to my daughter, both times on the highway. One time the car shut down completely and the 2nd time the car just started slowing while pressing the gas and coasted to a stop. Luckily she was able to avoid other cars and get to the shoulder. The car restarted both times. . . 1st time after about an hour wait and 2nd time within minutes. Both incidents happened when the gas gauge was at 2 bars. I am terrified of this thing right now. No warning signs at all prior to the incident. I took it to the dealer after the first incident but they could not figure out what the problem was as they were not able to recreate the issue. This is an extremely unsafe issue and I am not sure what I should do next.

The contact owned a 2021 Subaru Forester. The contact stated that while driving at approximately 4 mph and slowing to park, the vehicle accelerated on its own. The contact stated that the vehicle drove out of the parking lot and crashed into a wall. The contact stated that the air bags deployed and that the vehicle had then shifted into reverse (r) and driven out away from the wall and crashed into a parked vehicle and stopped. The contact stated she was unaware of any warning lights. The contact stated that she had 1 passenger in the front seat and 2 passengers in the rear seat. The contact stated that everyone was shaken and achy, but no cuts or other injuries. The contact stated later that the passengers went on their own to seek medical attention. The contact stated that the passenger front bumper, hood, and wheel well were damaged, and the rear bumper on the passenger side had damage from the crash with the parked vehicle. The contact stated that the other vehicle had minor damage to the right rear quarter panel. The police were called and issued a report. The vehicle was towed to a collision repair shop, but had not been repaired. The vehicle had not been diagnosed for the independent acceleration and reverse failures. The contact stated that her insurance provider had not yet declared the vehicle a total loss. The manufacturer was not informed of the failure. The failure mileage was approximately 30,000.

This 2020 Subaru Forester has experienced repeated failures involving the auto start/stop system. When stopped in traffic, the system shuts the engine off as designed, but on multiple occasions the engine has failed to restart normally when the driver needed to proceed. This has left the vehicle unable to move in active traffic and created a serious risk of collision. The failures have occurred in highly dangerous situations, including a busy [xxx], a major [xxx] intersection, and most recently while entering a freeway. In these incidents, surrounding drivers had to brake hard to avoid striking the disabled vehicle. The occupants reasonably feared a serious collision, and the events were potentially life-threatening. The battery was replaced, but the auto start/stop no-restart condition later occurred again, so battery replacement did not resolve the problem. Subaru issued technical service bulletin 16-147-24 on xxx for 2019-2021 Foresters. The bulletin addresses tcm reprogramming related to engine behavior during auto start/stop restart and instructs technicians to reprogram the tcm when the described symptom is reported. However, the bulletin’s warranty section provides reimbursement under the basic new car limited warranty. For a 2020 vehicle, the original 3-year/36,000-mile basic warranty would ordinarily have expired before this 2024 bulletin was issued. The vehicle is now being evaluated by an authorized Subaru dealer. The condition is intermittent and dangerous because the driver cannot know whether the engine will restart when movement is required. The vehicle is available for inspection. Information redacted pursuant to the freedom of information act (foia), 5 u. S. C. 552(b)(6).

My son, [xxx] is currently driving this car. The car only has 29,200 miles so far. Last week, while at the stop light on the hill, he had near fatal accident! Forester suddenly completed shut down. The only functioning part was the brake. My son had to put the car in park and restart the engine. I reported the incident to customer advocate at Subaru and taking the car in for inspection. We never skip any scheduled maintenance. My next maintenance not due until April. I also purchased Subaru safety monitoring software. The car never shows any malfunction. It’s a very serious issue. We strongly suspect it’s related to the start-stop system on this car. We strongly support to override the system at consumer level giving their unreliability. Thank you for your attention to this matter. Sincerely, [xxx] information redacted pursuant to the freedom of information act (foia), 5 u. S. C. 552(b)(6).

The a/c compressor seized up causing the belt to break. Looked up online and it seems it's a common occurrence with this year and model.

On 3 different occasions the car randomly accelerated at a high speed without stepping on the gas pedal. The first time was in a parking lot. The second time was on a busy road while traveling at 35 mph. The car accelerated to about 60 mph, fortunately once applying the brakes the vehicle slowed down to gain control. The third time it happened was recently on [xxx] while slowly backing down [xxx]. The car accelerated backwards at a very high speed narrowly missing a fence in the neighbors yard. These incidents have happened with large time frame gaps in between the occurrences. After the third incident I took the car to a dealer planet Subaru in hanover MA. After keeping the car for a few days, the dealer called and said that they could not find anything wrong with the car and there was nothing that they could do for me. This issue is obviously very serious, if the car surges forward randomly while someone is crossing in a crosswalk it could be potentially fatal. Information redacted pursuant to the freedom of information act (foia), 5 u. S. C. 552(b)(6).

On january16,2026 while driving from houston,TX to austin TX the vehicle experienced a complete loss of power on highway 71 w. We were traveling at approximately 70 mph when the engine completely failed. We were forced to immediately pull over onto a narrow shoulder our situation at that point was dire: we could not exit the vehicle as other cars were speeding by. Fortunately an emergency vehicle from the texas department of transportation pulled up behind us with his emergency lights flashing. He told us we were in a dangerous situation and, due to our location, he was not able to tow us to safety. Our only option at that point was to allow the emergency vehicle to puss us to a safe location off of the highway. The driver pushed our vehicle approximately 1/2 mile to a motel parking lot. We contacted austin Subaru, arranged for a tow truck, and proceeded to the dealer. The dealer technician advised us the thermo control valve had failed. We were told this failure was common. The repair was at no charge since Subaru, being aware of the problem, had extended the warranty on this part. The action by Subaru to extend the warranty instead of proactively replacing the part before failure seems blatantly irresponsible.

Took to local dealership for 20,000 mile oil change. After the oil change the service advisor informed me of an oil leak on the right side of the engine. He could not confirm where the leak was from. I have scheduled to have it repaired under factory warranty. After researching on the internet it has been noted that the valve cover/ spark plug boot seals are known to split and cause an engine oil leak. I am concerned that this oil leak could come in contact with the exhaust manifold which may lead to an engine compartment fire. Would your administration department please check into this concern.

See all problems of the 2024 Subaru Forester 🔎.

Car drains battery. 45,000 miles and has had 3 batteries and have been told it needs another. Dealer says start stop switch, requires a battery of 750 cca and not the Subaru recommend battery. Car will die in traffic and driver seat adjusts to different positions by itself. Told that these problems will never stop unless I get a higher rated battery than required.

Engine lost power and was misfiring while many warning symbols appeared on the dash. There was a divider separating the lanes. The car coasted to almost to a stop, but the engine chugged enough to slowly turn left at the first opening in the divider and just barely made it off the main road. The engine stopped. I restarted it several times. The engine was misfiring barely running. The electric brake was applied on its own. The car did not respond to moving the shift selector out of park, so the car was immobilized. I put the 4-way flashers on and called aaa. There seemed to be no way for me to move it out of park or release the electronic parking brake. Aaa could not respond quickly and suggested I call the police to divert traffic around my car for safety which I did. The tow truck operator was able to disengage the wheels and was able to flatbed it to the nearest repair shop. This being Saturday 1/3/26 it wasn't until Tuesday the repair shop determined the car would not run long enough to provide a reliable diagnosis due to the multiple trouble codes coming up on the computer analysis. I had the car towed to the nearest Subaru dealership who replaced the thermos control valve under their warranty extension. The dealership said usually when this part fails it just triggers a check engine light and not the dangerous situation I experienced. I believe a recall to replace this part should be issued on all cars with this defective part as its failure can cause a dangerous situation without warning.

See all problems of the 2019 Subaru Forester 🔎.

On 5/15/2024 and 5/21/2024 I had sudden uninteded acceleration. I had a auto shop try to solve the problem by replacing the air fuel ratio sensor and the mass air flow sensor. This seem to fix the issue until 11/27/2025 & 12/7/2025 when the sudden uninteded acceleration returned.

See all problems of the 2014 Subaru Forester 🔎.

While driving my 2020 Subaru Forester at approximately 15 mph, the engine unexpectedly shut off, resulting in an immediate loss of propulsion (vehicle stall while in motion). This created a safety risk because the vehicle was in traffic and could have been struck from behind or lost the ability to accelerate out of danger. No crash occurred and there were no injuries. There were no warning lamps, warning messages, check engine light, or limp mode before, during, or after the stall event. The vehicle later experienced catastrophic engine failure, also without any warning indicators. The vehicle has been inspected by an authorized Subaru dealership. The dealership confirmed the failure and diagnosed crankshaft bearing failure on cylinder 3, and recommended short block replacement along with related engine component replacement (including cam phasers and gaskets/seals). The engine/vehicle remains available for inspection upon request. Manufacturer has been notified through Subaru of America customer advocacy. Subaru has offered partial goodwill assistance but has declined further escalation or full remedy. Note: I have video of this showing no engine lights however unable to upload it below. Can send via email if required. Thank you. [xxx] information redacted pursuant to the freedom of information act (foia), 5 u. S. C. 552(b)(6).

I have reported this before but it never went anywhere. When at a red light or in a traffic slowdown, the car will activate the auto start/stop system. Three times in the past 2 days, the car would not turn back on and required me to turn the car off and back on again. You can imagine that this leaves me in a dangerous situation because the cars behind me see a green light and get ready to move, or they see traffic clearing up and they get ready to move. I am forced to turn my car off and back on again in the middle of a 4 lane highway or on a busy city street. I get cursed at and nearly rear ended each time this happens. I did an internet search and there are entire threads dedicated to this exact problem with this Subaru model and year. There should be a recall. It is very unsafe.

The engine in my 2010 Subaru Forester (VIN: [xxx] ) suffered a sudden and complete mechanical failure on November 15, 2025. While driving, the vehicle abruptly lost power without any warning lights or messages. I was able to pull off the roadway, but the loss of power posed a significant safety risk. Had this occurred in traffic or at highway speeds, it could have caused a collision. The vehicle was inspected the next business day by wiygul automotive. Their technicians found no measurable oil on the dipstick and added three quarts just to restart the engine. They confirmed no external oil leaks, and diagnosed the failure as a catastrophic internal oil consumption defect that had been occurring over time. This defect resulted in oil starvation and severe internal engine damage. The engine is fully available for inspection upon request. Wiygul provided a written diagnostic report confirming the cause of failure. The dealership has been notified but has not yet performed an inspection. ?no manufacturer, insurance, or law enforcement inspections have occurred to date. Importantly, the vehicle had a documented pre-purchase inspection on August 7, 2025, which noted the engine oil was significantly overfilled by approximately one quart and that all diagnostic codes had recently been cleared. These findings are consistent with an existing engine issue that would not be detectable by an ordinary consumer. On August 28, 2025, a full synthetic oil service was performed and again documented no external leaks. There were no symptoms, warnings, or drivability indications prior to the sudden loss of power. The failure occurred without warning, and the underlying defect was only discovered after the breakdown. This internal oil consumption defect rendered the vehicle unsafe and unfit for use, and the sudden engine shutdown created a clear risk to my safety and the safety of others on the road. Information redacted pursuant to the freedom of information act (foia), 5 u. S. C. 552(b)(6).

See all problems of the 2010 Subaru Forester 🔎.

Exhaust gas smell from the engine compartment when parked after driving. Garage smells like exhaust gases when left in enclosed garage - ongoing problem. Smell dissipates overnight. It has been inspected by Subaru dealers in albuquerque and santa fe new mexico. They report no error codes and so no problem. Have not had this issue on any other vehicle we've ever owned. There are no warning lamps or messages.

The vehicle has experienced four separate engine shutdowns while stopped in traffic. Each time, the engine turned off unexpectedly, requiring a manual restart. One incident occurred near a railroad crossing with my child in the car. The vehicle also lurches forward at low speeds and hesitates when accelerating after being stopped. These issues persist despite service visits. I believe they may relate to technical service bulletins regarding the auto start/stop and battery systems (tsbs #16-147-24, #10232217, #07-218-23r, #10251098). Subaru service staff have acknowledged awareness of these problems. I’m submitting this complaint to ensure the safety risk is documented and investigated.

I was steering my car into my own garage as I do daily. Suddenly, as the car was making the turn, the car accelerated abruptly on its own. I was somehow able to steer into the garage, but the rapid acceleration continued. I braked and stopped the car just before it went into the wall that adjoins the interior of my home. There was an inch to spare. There were no warnings or messages or sympoms prior to this event.

See all problems of the 2022 Subaru Forester 🔎.

I hit a deer going 45 mph, the air bags deployed, and my engine caught on fire. Within 10 minutes my car burned to the ground.

2020 Subaru Forester periodically will stall out at a light or stop sign in heavy traffic. It then takes several attempts to restart. (sometimes completely dead) my mechanic hasi changed the battery and checked the alternator, all in working order. It’s hard to figure out what is wrong because it doesn’t happen all the time.

When stopped at an intersection the car stalled. It would not restart for three minutes and caused a dangerous situation for my family and children in the car while traffic was moving. There were no warning signs, lights, or engine codes. The problem is random and cannot reproduced. The car is available for inspection.

We were traveling in rural California, 1 hour north of bishop, CA on CA-120 when our vehicle's "check engine" light, "parking break" light, and several other lights lit up on our dashboard. Our car began to stall out immediately. We were able to pull off to the side of the road as best as we could as we were towing a camper at the time as well. We waited for 4 hours to get our vehicle and camper towed 1 hour away to a mechanic. The mechanic couldn't fix our car, but we were able to get an engine code reader to clear the codes as they came up. The closest Subaru dealership was 4 hours away in las vegas, nv. We had to drive through mountains and death valley. Despite using the engine code reader to clear codes every 30 seconds, our car stalled out 6 times on the way. The problem was the thermo control valve for p26a6, a known problem with Subaru vehicles like ours. We had our vehicle serviced in July 2025 for 60,000 miles and the dealership did not say anything about this known issue.

Car has died 10+ times in the last 2 weeks. Will not hold a charge and it’s getting to the point that my car is dying in the middle of the road, during heavy traffic. That or the car will just not start unless jumped.

I, the owner of a 2020 Subaru Forester am writing to you in regards to an issue with my vehicle’s eyesight program. Over the past month, there have been several instances where the eyesight program fails and caused the vehicle to suddenly stop without warning. This prevents me from safely moving the vehicle to the side of the road as the car stops. In other words, the car abruptly stops on the spot. This creates an immediate danger to life and health to myself and to other motorists. This issue must be addressed immediately and the necessary steps taken to ensure the safety the driver, passengers and other motorists on the road. Thank you for understanding.