NHTSA complaint #11564774

Owner complaint summary

Thermo control valve failed at about 42000 miles on 2021 Subaru Forester Premium, on 1/1/24. Owned 3 yrs 1 mo. Car was parked at work. Immediately after car was started up for return commute -- check engine light was on, ADAS systems ("Eyesight") disabled, blue low coolant temperature light on, and no heat through HVAC. Fortunately car driveable, despite safety being compromised with disabling of the safety features (blind spot monitor, rear cross traffic alert) and concern about damaging engine being forced to drive home with check engine light on. Engine failed to warm despite 40+ min highway trip. As this was commute vehicle, forced to take next day off work to have check engine light looked at. The next morning windshield ice had to be manually scraped (no heat). Drove car gingerly to dealership (<10 mins) avoiding freeways, for fear of damaging engine. Unknown if windshield defroster would've worked if started fogging mid-trip (safety concern). Dealership inspected vehicle - diagnosed thermo control valve failure, and replaced part. I was not charged as the car was still covered under powertrain warranty. No warning prior to the failure. Drove normally on the morning drive to work. Dealership replaced TCV with a part that has the same part number, per Subaru's TSB. Given experience of others indicating high failure rates of TCV after 3-4 years, and what I suspect is genuine design defect, I expect replacing the part to only have temporarily reset the clock -- seems certain to fail again. I have no confidence that Subaru has implemented an actual solution. I do not know if the next failure of this powertrain component will happen under warranty, or if it will incur signficant out of pocket costs (well over >$1000 to replace). Furthermore, if TCV fails whilst driving (as could have happened, and has been reported by others elsewhere), this will be a safety hazard with sudden disabling of blind spot monitor / rear cross traffic alert.