2024 GMC Sierra 3500

The service department has identified "gasoline contamination" as the cause of a fuel system failure; however, this diagnosis is directly contradicted by both the shop’s internal test results and independent laboratory analysis.the shop performed an API Gravity test and a Styrofoam cup test.•API Gravity Result (35): According to GM Service Information (GMSi), the standard API range for #2 diesel is 30–39. result of 35 is a textbook "pass" for clean diesel. Gasoline contamination would typically spike this number into the 50s.GMSi protocol indicates that gasoline-contaminated diesel will melt a cup within 30 minutes.results only provided a "softened bottom," which is an inconclusive result per GMSi standards.Sinclair Refinery lab confirms the fuel sample taken from my vehicle is within 100% of factory specifications for diesel, with zero gasoline or DEF detected.Violation of GM Service Protocols even assuming the shop’s diagnosis of contamination was correct, the repair performed deviates dangerously from GMSi requirementsFor a 2024 L5P Duramax that has been cranked with contaminated fuel, GMSi (e.g., Bulletin 16-NA-376) mandates the replacement of the entire high-pressure fuel system, including the pump, both fuel rails, and all eight fuel injectors. shop replaced only the pump and cleaned the lines. This "partial repair" is not a GM-approved recovery procedure for contamination. Reusing potentially contaminated injectors and rails is the primary cause of catastrophic repeat failures.This clearly falls under warranty work and I should not had been charged for this repair. The dealership refusing to acknowledge my concerns and evidence is not only dangerous to the safety of myself and passengers, but raises concern for my vehicles future maintenance status, both inside and out of warranty. This shows a deceptive business practice and complete lack of accountability, compassion and moral understanding for the customer.I am owed a full refund and a warranty claim open

First incident we were driving on the interstate towing a fifth wheel RV, and several warning lights illuminated before everything just shut down. Manage to get to the side of the road. Vehicle finally restarted and the rest of the trip was uneventful. Second incident, vehicle had not run for two days, got in and while the starter cranks, the engine will not start or run. Engine/Transmission service and fuel system service messages showing on app and on email from OnStar. Vehicle requires towing to dealer.