6 Motor Oils To NEVER Put in Your GMC (And 4 That Make It Last Forever)

📩 Business: everythinggmc88@gmail.com ━━━━━━━━━━━━━━━━━━━━━━━━━━━ 📘 THE 500,000-MILE GMC BLUEPRINT The complete maintenance system for making your gmc last past 500,000 miles — including the service that stops a $7,000 AFM lifter failure. 👉 https://everythinggmc.gumroad.com/l/o... ━━━━━━━━━━━━━━━━━━━━━━━━━━━ I'm Dale, twenty-eight years on the bench. Six motor oils to never put in your GMC, and four that make it last forever — because since 2021, the right answer stopped being a brand and became a specification. ⚠️ THE 6 TO AVOID — these are TYPES, not brands. Any oil from a serious manufacturer carrying the dexos1 license is fine for your truck. There is no list of six bad brands. 6️⃣ ANY OIL WITHOUT THE DEXOS1 LICENSE (on a 2011+ GM gas engine) — That seal isn't marketing. The blender submits the formulation to GM, runs GM's test battery, and gets licensed. Without it you have zero validation. It also matters if you're ever in a warranty conversation. 5️⃣ CONVENTIONAL OIL IN A MODERN GDI OR TURBO ENGINE — Oxidizes faster under sustained heat, and older conventional formulations have no LSPI protection. ⚠️ Honest: on an older port-injected engine (LM7, LQ4, 4.8), quality conventional at a short interval is not a crime. I still run synthetic, because the price gap is a few dollars a jug and you're buying margin. 4️⃣ OBSOLETE API CATEGORIES (SN, SM, SL) — Flip the bottle over and read the donut. Current is API SP, which replaced SN Plus in 2020. The older categories were written before the LSPI test existed. That's not weaker protection — it's the absence of it. 3️⃣ THE WRONG VISCOSITY FOR YOUR ENGINE — There's no such thing as "0W-20 is better than 5W-30." Viscosity is a design input. Gen V engines are generally built around 0W-20; many older Gen III/IV engines call for 5W-30. Your oil fill cap has the answer. ⚠️ CRITICAL EXCEPTION: if you have the 6.2L L87, recall 25V-274 moves that engine to Dexos R 0W-40. Say it out loud at the counter — a parts lookup by year will hand somebody 0W-20 in good faith. 2️⃣ RACING OIL IN A STREET TRUCK — Lighter detergent packages (a race engine gets drained the same night), often elevated zinc (phosphorus is a catalyst poison), and most of it isn't licensed at all. High-zinc oil has a legitimate home: a flat-tappet cam. Your GM V8 is roller-cammed from the factory. 1️⃣ UNVERIFIABLE BULK "HOUSE BLEND" — Bulk oil isn't bad; my shop buys bulk, dealers buy bulk. The problem is the unverifiable drum. When it's poured from a hose you can't read the seal, the donut, or the viscosity. Ask what spec and what weight, and ask them to write it on the invoice. A good shop answers in four seconds. ✅ THE 4 THAT MAKE IT LAST 4️⃣ HIGH-MILEAGE FULL SYNTHETIC (dexos-licensed) — Seal conditioners for an aged engine. NOT a fix for a leak. That's a gasket, not an additive. 3️⃣ DEXOS1 GEN 3 FULL SYNTHETIC, 5W-30 — For the older engines. A 2004 LM7 has never had oil this good available to it. 2️⃣ DEXOS1 GEN 3 FULL SYNTHETIC, 0W-20 — The current standard for Gen V. Gen 3 arrived in 2021, requires API SP, adds timing chain wear testing, and supersedes Gen 2. 1️⃣ DEXOS R 0W-40 — Mandatory on the L87 after the recall, and GM's spec for high-speed, high-load duty. Don't pour it where it isn't specified. Don't let anyone replace it with something thinner where it is. 💡 SPEC BEATS BRAND. Two bottles from two reputable blenders, both dexos1 Gen 3, both the right viscosity, will serve your truck the same. Mobil 1, Pennzoil Platinum, Valvoline, Castrol Edge, AMSOIL, ACDelco all carry the license. Pick one you can get consistently. And the interval beats the brand too. Never past 12 months regardless of what the monitor shows. Don't pour additives into a licensed oil — it's already a balanced package that was tested as a system. Spec. Viscosity. Interval. Filter. Nothing else. What's in your truck right now? Drop it in the comments. #GMC #GMCTrucks #GMCSierra #MotorOil #Dexos1 #LSPI #OilChange #AFM #CarMaintenance #EverythingGMC