There are 1 owner-reported engine complaints for the 2018 Chevrolet Sonicin NHTSA's database. These are unverified consumer reports and may not reflect confirmed defects.
Dear GM Executive Office, I am writing in frustration and disappointment after being told today by Chevrolet Customer Assistance that the case I opened (Case # [XXX]) was simply a "dealer complaint" and that no further help would be offered - despite my vehicle exhibiting a recurring, safety-related malfunction covered under Special Coverage N232395330 - Turbocharger Replacement. To Whom It May Concern, I am writing to formally request a resolution regarding a recurring and unresolved issue with my son’s 2018 Chevrolet Sonic Premier (Turbocharged engine), VIN: [XXX] This past January we brought the vehicle to Ziegler Buick GMC of Lincolnwood an authorized due to overheating and a warning light. We paid $210 for a diagnosis and an additional $520 for a repair, totaling $730. The only action taken was the replacement of the coolant reservoir. The issue was not fully diagnosed, and the root cause was not addressed. On [XXX], the same issue has returned: Red heat warning light illuminated after less than one mile of driving. Coolant reservoir nearly empty upon inspection. Engine went into reduced power (“limp mode”). Scanner showed only a low coolant level but no additional actionable codes. Vehicle also displayed a change oil warning, likely triggered by overheating. This vehicle has a known history of turbocharger and coolant system defects, which have been acknowledged in GM technical service bulletins and Customer Satisfaction Programs. I have reason to believe this situation qualifies for one of those programs. Despite paying $730 for a prior repair, the vehicle is now exhibiting the same safety-related malfunction, putting my son at risk of engine damage and breakdown. We have also taken the car to Mike Anderson Chevrolet twice for inspection and they reported finding nothing. I am respectfully requesting the following: A thorough inspection and diagnosis of the entire cooling system and turbocharger INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
Complaints are unverified consumer reports submitted to NHTSA. A high complaint count may reflect vehicle popularity, not defect severity. Data sourced from NHTSA public records.
Data synced from NHTSA on Apr 26, 2026