The 2018 GMC Sierra 1500 belongs to the K2XX generation (2014-2018), built with 4.3L EcoTec3 V6 (LV3/LV1), 5.3L EcoTec3 V8 (L83, AFM), or 6.2L EcoTec3 V8 (L86, AFM) - 6L80/6L90 6-speed automatic, or 8L90 8-speed from MY2015 (6.2L) / MY2017 (select 5.3L). It takes dexos1 full synthetic - 0W-20 (5.3L/6.2L V8) or 5W-30 (4.3L V6). Oil changes run 7,500 miles typically, per the GM Oil Life Monitor. This is the final model year of that generation, usually the most sorted version of the design before the redesign that followed.
A 2018 GMC Sierra 1500 is 8 years old in 2026, which at an average 12,000 miles a year puts it around 96,000 miles - the interval that decides its future. At roughly 96,000 miles a vehicle enters the window that most separates the ones that reach 200,000 miles from the ones that do not. Keeping up with whatever its own manufacturer schedule calls for here is what avoids expensive failures later. The next milestone on its own schedule is 120,000 miles, roughly 2 years away at average use - a repeat of the 30,000-mile service.
The fault most worth knowing about on this generation is Cracked dashboard and AC condenser leaks are common cosmetic/reliability complaints across 2014-2018 GM full-size trucks. Owners also report AFM lifter failure on the 5.3L L83 and 6.2L L86 - collapsed lifters cause a cylinder misfire and audible tick; and 8L90 shudder at light throttle on 6.2L and later 5.3L 8-speed trucks - a full DEXRON-VI exchange resolves most cases. None of these are certainties on any individual vehicle - they are the patterns worth checking for when you buy or when a symptom appears.
Track your 2018 GMC Sierra 1500 service history free with the ServiceSage maintenance tracker, or compare it against other model years on the GMC Sierra 1500 maintenance schedule hub.
| Interval | Service |
|---|---|
| Every 7,500 mi (per GM Oil Life Monitor) | Engine oil and filter change with dexos1 full synthetic (0W-20 for 5.3L/6.2L V8; 5W-30 for 4.3L V6), Reset the Oil Life Monitor, Check tire inflation pressure |
| Every 7,500 mi | Rotate tires and perform Required Services, Visually inspect steering, suspension, and chassis components, Visually check for fluid leaks |
| Every 22,500 mi | Replace passenger compartment (cabin) air filter |
| Every 45,000 mi | Inspect evaporative control system fuel/vapor lines and hoses, Replace engine air cleaner filter |
| Every 45,000 mi (severe duty: towing/off-road/plowing) | Change automatic transmission fluid and filter, Change transfer case fluid, if equipped with 4WD |
| Every 22,500 mi (extreme 4WD off-road/farming/mining/forestry/plowing use only) | Change transfer case fluid, if equipped with 4WD |
| Every 97,500 mi (normal duty) | Replace spark plugs and inspect spark plug wires - all three gas engines (8 plugs, V8; 6 plugs, V6), Change automatic transmission fluid and filter (normal duty), Change transfer case fluid, if equipped with 4WD (normal duty) |
| Every 150,000 mi (or 5 years) | Drain and fill engine cooling system with DEX-COOL |
| Every 150,000 mi (or 10 years) | Visually inspect accessory drive belts; replace if frayed, cracked, or damaged, Replace brake fluid |
The table above is indexed by service interval. This is the same schedule indexed by odometer reading, for when you know your mileage and want the list. If your odometer sits between these figures, work back to the last one you passed and catch up anything skipped.
| Odometer | Service due |
|---|---|
| 30,000 mi (48,000 km) | Engine oil and filter change with dexos1 full synthetic (0W-20 for 5.3L/6.2L V8; 5W-30 for 4.3L V6), Reset the Oil Life Monitor, Check tire inflation pressure, Rotate tires and perform Required Services, Visually inspect steering, suspension, and chassis components, Visually check for fluid leaks. The every-22,500 mi service runs on its own cycle - the nearest fall at 22,500 and 45,000 miles. |
| 60,000 mi (97,000 km) | Same as the 30,000 mi service. The every-22,500 mi service runs on its own cycle - the nearest fall at 45,000 and 67,500 miles. |
| 90,000 mi (145,000 km) | Engine oil and filter change with dexos1 full synthetic (0W-20 for 5.3L/6.2L V8; 5W-30 for 4.3L V6), Reset the Oil Life Monitor, Check tire inflation pressure, Rotate tires and perform Required Services, Visually inspect steering, suspension, and chassis components, Visually check for fluid leaks, Replace passenger compartment (cabin) air filter, Inspect evaporative control system fuel/vapor lines and hoses, Replace engine air cleaner filter. |
| 120,000 mi (193,000 km) | Same as the 30,000 mi service. The every-22,500 mi service runs on its own cycle - the nearest fall at 112,500 and 135,000 miles. |
| 150,000 mi (241,000 km) | Engine oil and filter change with dexos1 full synthetic (0W-20 for 5.3L/6.2L V8; 5W-30 for 4.3L V6), Reset the Oil Life Monitor, Check tire inflation pressure, Rotate tires and perform Required Services, Visually inspect steering, suspension, and chassis components, Visually check for fluid leaks, Drain and fill engine cooling system with DEX-COOL, Visually inspect accessory drive belts; replace if frayed, cracked, or damaged, Replace brake fluid. The every-22,500 mi service runs on its own cycle - the nearest fall at 135,000 and 157,500 miles. |
| Part | Fitment note | Buy |
|---|---|---|
| Mobil 1 0W-20 Full Synthetic (5 qt) | dexos1-approved 0W-20 for the 5.3L and 6.2L V8 | Check price on Amazon |
| Mobil 1 dexos1 5W-30 Full Synthetic (5 qt) | dexos1-approved 5W-30 for the 4.3L V6 | Check price on Amazon |
| ACDelco PF63 Engine Oil Filter | OEM spin-on filter, all three K2XX Sierra engines | Check price on Amazon |
| ACDelco 41-114 (12622441) Iridium Spark Plug | 97,500-mile iridium plugs for L83/L86 (use 6 for the 4.3L V6) | Check price on Amazon |
| GM Genuine DEXRON-VI ATF Transmission Fluid (1 qt) | Required for the 6L80, 6L90, and 8L90 transmissions | Check price on Amazon |
| ACDelco 10-101 DEX-COOL Extended Life Coolant (1 gal) | Orange DEX-COOL - do not mix with green conventional coolant | Check price on Amazon |
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| Fastener | Torque | Size |
|---|---|---|
| Lug nut | 140 ft-lbs (190 Nm) | 22mm |
| Oil drain plug | 18 ft-lbs (25 Nm) | 15mm |
Maintenance keeps these away, but when the dash does light up these are the codes this vehicle throws most often - each with what it means and what the repair actually costs.