2026 GMC Sierra 3500 Engine Parts

This table covers the camshafts that open the valves. Read more

This group shows a single part: GM GENUINE 12672469.

This table covers the Camshaft bearings. Typical signs include a growl that rises with speed, or play in the shaft or hub. Set preload the way the notes specify. A dry or crushed bearing fails quickly. Read more

3 Camshaft Bearing parts for the 2026 GMC Sierra 3500 come from GM GENUINE.

Part numbers include GM GENUINE 19260878, GM GENUINE 19260879 and GM GENUINE 12679049.

This table covers the Camshaft bolts. Read more

One part is listed for the 2026 GMC Sierra 3500 — GM GENUINE 11561455.

This table covers the Camshaft Dowel pins. Read more

This group shows a single part: GM GENUINE 24575061.

This table covers the Camshaft Retainer / Thrust plates. Typical signs include warpage, cracks, or a plate that no longer locates the assembly. Confirm which plate the notes describe — backing plates, clutch plates and strike plates are different parts. Read more

One part is listed for the 2026 GMC Sierra 3500 — GM GENUINE 12589016.

This table covers the bearings in the connecting-rod big ends. Typical signs include a growl that rises with speed, or play in the shaft or hub. Set preload the way the notes specify. A dry or crushed bearing fails quickly. Read more

This group shows a single part: GM GENUINE 12735504.

This table covers the Connecting Rod bolts. Read more

One part is listed for the 2026 GMC Sierra 3500 — GM GENUINE 11548432.

This table covers the Crankcase pressure sensors. Typical signs include a check-engine light for MAP or fuel-rail pressure, or a limp mode under load. A vacuum leak or a clogged reference line will fake a bad pressure sensor. Read more

One part is listed for the 2026 GMC Sierra 3500 — GM GENUINE 12814873.

This table covers the crankshafts that turn piston motion into rotation. Read more

This group shows a single part: GM GENUINE 12708884.

This table covers the main bearings that support the crankshaft in the block. Typical signs include a growl that rises with speed, or play in the shaft or hub. Set preload the way the notes specify. A dry or crushed bearing fails quickly. Read more

One part is listed for the 2026 GMC Sierra 3500 — GM GENUINE 12729655.

This table covers the Crankshaft Main Bearing Cap bolts. Read more

3 Crankshaft Main Bearing Cap Bolt parts for the 2026 GMC Sierra 3500 come from GM GENUINE.

Listed part numbers: GM GENUINE 11546565, GM GENUINE 11548076 and GM GENUINE 11548075.

This table covers the front and rear seals that keep oil in at the crankshaft. Typical signs include a wet housing, a drip after sitting, or fluid flung off a rotating shaft. Fix the surface the seal rides on. A new seal on a grooved shaft will leak again. Read more

GM GENUINE supplies both parts for the 2026 GMC Sierra 3500.

Listed part numbers: GM GENUINE 12634614 and GM GENUINE 12665076.

This table covers the Crankshaft Seal covers. Read more

This group shows a single part: GM GENUINE 12705664.

This table covers the gaskets that seal the Crankshaft Seal. Typical signs include seepage at the joint, a burnt-oil smell, or a leak that appears only after a long drive. Clean both flanges and torque in the sequence the notes or the manual call for. Read more

This group shows a single part: GM GENUINE 12627520.

This table covers the cylinder heads that close the top of the block. Read more

One part is listed for the 2026 GMC Sierra 3500 — GM GENUINE 12705857.

This table covers the Cylinder Head Alignment Dowel pins. Read more

This group shows a single part: GM GENUINE 12570326.

This table covers the bolts that clamp the cylinder head to the block. Read more

2 Cylinder Head Bolt parts for the 2026 GMC Sierra 3500 come from GM GENUINE.

This group includes GM GENUINE 11611976 and GM GENUINE 11546959.

This table covers the head gaskets that seal the block to the cylinder head. Typical signs include seepage at the joint, a burnt-oil smell, or a leak that appears only after a long drive. Clean both flanges and torque in the sequence the notes or the manual call for. Read more

This group shows a single part: GM GENUINE 12688186.

This table covers the Cylinder Head plugs. Typical signs include a leak at the drain or glow-plug hole, or a plug that has rounded off. Replace the crush washer and torque to the spec in the notes. Read more

One part is listed for the 2026 GMC Sierra 3500 — GM GENUINE 24502262.

This table covers the Engine Block drain plugs. Read more

2 Engine Block Drain Plug parts for the 2026 GMC Sierra 3500 come from GM GENUINE.

Part numbers include GM GENUINE 11602951 and GM GENUINE 11546667.

This table covers the block heaters that warm the coolant or oil in cold weather. Read more

One part is listed for the 2026 GMC Sierra 3500 — GM GENUINE 12586687.

This table covers the Engine Cover grommets. Read more

One part is listed for the 2026 GMC Sierra 3500 — GM GENUINE 12594875.

This table covers the exhaust valves that let combustion gas out of the cylinder. Typical signs include a circuit that will not hold, a whistle, or a code for this valve. A stuck valve is often debris. Clean the ports before installing the new one. Read more

One part is listed for the 2026 GMC Sierra 3500 — GM GENUINE 12733470.

This table covers the crankshaft pulleys / harmonic balancers at the front of the engine. Read more

This group shows a single part: GM GENUINE 12680364.

This table covers the Harmonic Balancer bolts. Read more

One part is listed for the 2026 GMC Sierra 3500 — GM GENUINE 11547372.

This table covers the Intake manifolds. Typical signs include an exhaust tick, a vacuum leak, or a gasket that has burned through. Replace the gaskets and hardware; a warped flange will leak with a new gasket alone. Read more

One part is listed for the 2026 GMC Sierra 3500 — GM GENUINE 12748172.

This table covers the Intake Manifold bolts. Read more

This group shows a single part: GM GENUINE 11610472.

This table covers the gaskets between the intake manifold and the cylinder head. Typical signs include seepage at the joint, a burnt-oil smell, or a leak that appears only after a long drive. Clean both flanges and torque in the sequence the notes or the manual call for. Read more

3 Intake Manifold Gasket parts for the 2026 GMC Sierra 3500 come from GM GENUINE.

Listed part numbers: GM GENUINE 12626354, GM GENUINE 12693081 and GM GENUINE 12642410.

This table covers the mounts that hold the engine to the chassis. Typical signs include a clunk on takeoff, a vibration at idle, or a separated rubber insert. Support the powertrain before unbolting a mount, and torque the fasteners in the notes. Read more

One part is listed for the 2026 GMC Sierra 3500 — GM GENUINE 85043935.

This table covers the engine oils listed by grade and specification for this engine. Typical signs include a low-oil lamp, knocking after a long interval, or oil that has gone thin and black well before the next service. Match the viscosity and spec in the notes (and on the filler cap). The tables group grades — they are not interchangeable. Read more

17 Oil parts are listed for the 2026 GMC Sierra 3500, from MOBIL, LIQUI MOLY, VALVOLINE and 2 other brands. ACDELCO 109324 carries the "Popular" badge.

In the Full Synthetic grade, LIQUI MOLY, MOBIL, VALVOLINE and 2 other brands supply 15 parts: full-synthetic oils. A representative part number is ACDELCO 109324.

The High Mileage (>75,000 Miles) section lists 2 options from MOBIL — oils grouped for high-mileage engines. MOBIL 103767 is listed in this group.

This table covers the gaskets that seal the Oil Cooler. Typical signs include seepage at the joint, a burnt-oil smell, or a leak that appears only after a long drive. Clean both flanges and torque in the sequence the notes or the manual call for. Read more

This group shows a single part: GM GENUINE 23129010.

This table covers the Oil Cooler lines. Typical signs include a wet fitting, a rusted pipe, or a pressure loss in this circuit. Flare or thread the new line the way the notes specify; a kinked replacement will fail early. Read more

One part is listed for the 2026 GMC Sierra 3500 — GM GENUINE 85724971.

This table covers the harness connectors at the Oil Cooler Line. Typical signs include an intermittent fault that moves when you wiggle the plug, green corrosion, or a melted housing. Match terminal count and keyway, not just color. Many families look identical and will not lock. Read more

This group shows a single part: GM GENUINE 84240295.

This table covers the seals at the Oil Cooler. Typical signs include a wet housing, a drip after sitting, or fluid flung off a rotating shaft. Fix the surface the seal rides on. A new seal on a grooved shaft will leak again. Read more

This group shows a single part: GM GENUINE 12631281.

This table covers the Oil Dipstick tubes. Read more

One part is listed for the 2026 GMC Sierra 3500 — GM GENUINE 12664925.

This table covers the seals at the Oil Dipstick / Tube. Typical signs include a wet housing, a drip after sitting, or fluid flung off a rotating shaft. Fix the surface the seal rides on. A new seal on a grooved shaft will leak again. Read more

2 Oil Dipstick / Tube Seal parts for the 2026 GMC Sierra 3500 come from GM GENUINE.

This group includes GM GENUINE 24504031 and GM GENUINE 12676951.

This table covers the drain plugs in the oil pan. Read more

GM GENUINE supplies both parts for the 2026 GMC Sierra 3500.

Part numbers include GM GENUINE 55577568 and GM GENUINE 12625298.

This table covers the crush washers and gaskets under the oil drain plug. Typical signs include seepage at the joint, a burnt-oil smell, or a leak that appears only after a long drive. Clean both flanges and torque in the sequence the notes or the manual call for. Read more

This group shows a single part: GM GENUINE 12616850.

This table covers the Oil Drain Plug inserts. Read more

This group shows a single part: GM GENUINE 11503302.

This table covers the caps on the oil filler neck. Read more

One part is listed for the 2026 GMC Sierra 3500 — ACDELCO FC279.

This table covers the gaskets that seal the Oil Filler Cap. Typical signs include seepage at the joint, a burnt-oil smell, or a leak that appears only after a long drive. Clean both flanges and torque in the sequence the notes or the manual call for. Read more

This group shows a single part: GM GENUINE 24100002.

This table covers the Oil Filler tubes. Read more

One part is listed for the 2026 GMC Sierra 3500 — GM GENUINE 12668614.

This table covers the oil filters that screw onto this engine's filter mount. Typical signs include low oil pressure after a service, or a filter that will not spin off because the old gasket stayed on the block. Lube the new gasket and tighten to the spec on the box; a double-gasket install dumps the sump on the first drive. Read more

10 Oil Filter parts are listed for the 2026 GMC Sierra 3500, from VARIOUS MFR, WIX, ACDELCO and 4 other brands. ACDELCO PF63 carries the "Popular" badge.

In the Economy grade, FVP, PRO-TEC and VARIOUS MFR supply 3 parts: the catalog's value-priced group. A representative part number is FVP R0255.

In the High Performance / Heavy Duty grade, MOBIL and WIX supply 2 parts: grouped under the catalog's "High Performance / Heavy Duty" designation — the notes column spells out what sets them apart. A representative part number is MOBIL M1212A.

The Standard Replacement section lists 5 options from ACDELCO, WIX, HASTINGS / BALDWIN and 1 other brand — built to original-equipment specification. ACDELCO PF63 is listed in this group.

This table covers the Oil Filter adapters. Read more

This group shows a single part: GM GENUINE 12600225.

This table covers the Oil Galley plugs. Typical signs include a leak at the drain or glow-plug hole, or a plug that has rounded off. Replace the crush washer and torque to the spec in the notes. Read more

One part is listed for the 2026 GMC Sierra 3500 — GM GENUINE 11546667.

This table covers the Oil Level sensors. Typical signs include a warning lamp, a stored code, or a reading that drops out when the harness is wiggled. Inspect the connector and ground before replacing the sensor — wiring faults are often condemned as bad sensors. Read more

One part is listed for the 2026 GMC Sierra 3500 — GM GENUINE 12696433.

This table covers the Oil Level Sensor Gasket O-rings. Typical signs include a seep at a fitting or a housing that weeps after a service. Lube the new O-ring with the fluid it will see, and do not roll it into the groove. Read more

One part is listed for the 2026 GMC Sierra 3500 — GM GENUINE 12638820.

This table covers the Oil nozzles. Read more

One part is listed for the 2026 GMC Sierra 3500 — GM GENUINE 12678499.

This table covers the oil pans that hold the engine's oil sump. Read more

This group shows a single part: GM GENUINE 12739177.

This table covers the Oil Pan bolts. Read more

GM GENUINE supplies both parts for the 2026 GMC Sierra 3500.

Listed part numbers: GM GENUINE 12554990 and GM GENUINE 11588725.

This table covers the Oil Pan covers. Read more

One part is listed for the 2026 GMC Sierra 3500 — GM GENUINE 12630766.

This table covers the gaskets between the oil pan and the block. Typical signs include seepage at the joint, a burnt-oil smell, or a leak that appears only after a long drive. Clean both flanges and torque in the sequence the notes or the manual call for. Read more

GM GENUINE supplies the 3 Oil Pan Gasket parts for the 2026 GMC Sierra 3500.

Part numbers include GM GENUINE 12666993, GM GENUINE 12623359 and GM GENUINE 12621086.

This table covers the Oil Pump bolts. Read more

This group shows a single part: GM GENUINE 11610074.

This table covers the Oil Pump Control Valve solenoids. Typical signs include a harsh or missing shift, or a code for this solenoid circuit. Check resistance and the connector before dropping the pan for a solenoid. Read more

This group shows a single part: GM GENUINE 12686431.

This table covers the seals at the Oil Pump Control Valve / Solenoid. Typical signs include a wet housing, a drip after sitting, or fluid flung off a rotating shaft. Fix the surface the seal rides on. A new seal on a grooved shaft will leak again. Read more

One part is listed for the 2026 GMC Sierra 3500 — GM GENUINE 12626252.

This table covers the gaskets that seal the Oil Pump. Typical signs include seepage at the joint, a burnt-oil smell, or a leak that appears only after a long drive. Clean both flanges and torque in the sequence the notes or the manual call for. Read more

This group shows a single part: GM GENUINE 12638433.

This table covers the windage trays that keep crank windage out of the oil sump. Read more

One part is listed for the 2026 GMC Sierra 3500 — GM GENUINE 12619978.

This table covers the pistons that travel in each cylinder. Typical signs include knock, blow-by, or a cylinder that will not hold compression. Piston work is a short-block job. Match bore, pin and ring pack in the notes — not the photo. Read more

4 Piston parts for the 2026 GMC Sierra 3500 come from GM GENUINE.

This group includes GM GENUINE 12699527, GM GENUINE 12699529 and GM GENUINE 12817339 and the remaining parts above.

This table covers the Piston Pin retainers. Read more

One part is listed for the 2026 GMC Sierra 3500 — GM GENUINE 01647383.

This table covers the rings that seal each piston to the cylinder wall. Read more

2 Piston Ring parts for the 2026 GMC Sierra 3500 come from GM GENUINE.

This group includes GM GENUINE 12735470 and GM GENUINE 12661872.

This table covers the pushrods that transfer lifter motion to the rocker arms. Read more

This group shows a single part: GM GENUINE 12619828.

This table covers the rocker arms that transfer cam motion to the valves. Read more

One part is listed for the 2026 GMC Sierra 3500 — GM GENUINE 12619829.

This table covers the Rocker Arm nuts. Read more

This group shows a single part: GM GENUINE 11546449.

This table covers the timing chains that keep the cams in time with the crank. Read more

This group shows a single part: GM GENUINE 12646387.

This table covers the tensioners that keep the timing chain taut. Typical signs include belt flutter, a chirp that returns after a new belt, or an arm that no longer damps. Replace the tensioner with the belt at higher mileage. Read more

GM GENUINE supplies both parts for the 2026 GMC Sierra 3500.

This group includes GM GENUINE 11515758 and GM GENUINE 12630107.

This table covers the Timing covers. Read more

This group shows a single part: GM GENUINE 12691692.

This table covers the crankshaft sprockets that drive the timing chain or belt. Read more

One part is listed for the 2026 GMC Sierra 3500 — GM GENUINE 12713934.

This table covers the fasteners that mount the turbocharger. Read more

This group shows a single part: GM GENUINE 11547786.

This table covers the Turbocharger Up pipes. Read more

This group shows a single part: GM GENUINE 12688021.

This table covers the Valley Pan covers. Read more

This group shows a single part: GM GENUINE 12814373.

This table covers the Valve covers. Read more

2 Valve Cover parts for the 2026 GMC Sierra 3500 come from GM GENUINE.

This group includes GM GENUINE 12723317 and GM GENUINE 12727455.

This table covers the Valve Cover Bolt screws. Typical signs include a rounded head, a seeping bleeder, or a fastener that will not hold torque. Do not force a new screw into a stripped hole — repair the thread first. Read more

This group shows a single part: GM GENUINE 11547061.

This table covers the gaskets that seal the valve cover to the cylinder head. Typical signs include seepage at the joint, a burnt-oil smell, or a leak that appears only after a long drive. Clean both flanges and torque in the sequence the notes or the manual call for. Read more

One part is listed for the 2026 GMC Sierra 3500 — GM GENUINE 12619787.

This table covers the lifters / tappets that transfer cam motion to the valves. Read more

One part is listed for the 2026 GMC Sierra 3500 — GM GENUINE 12698945.

This table covers the guides that keep each lifter aligned. Read more

One part is listed for the 2026 GMC Sierra 3500 — GM GENUINE 12595365.

This table covers the springs that close each intake and exhaust valve. Typical signs include a sagging corner, a broken coil, or a clunk from the spring pocket. Replace springs in axle pairs and inspect the seats. Read more

This group shows a single part: GM GENUINE 12728733.

This table covers the Valve Spring retainers. Read more

This group shows a single part: GM GENUINE 10166344.

This table covers the keepers that lock each valve-spring retainer to the stem. Read more

This group shows a single part: GM GENUINE 10166345.

This table covers the seals on each valve stem that control oil into the guides. Typical signs include a wet housing, a drip after sitting, or fluid flung off a rotating shaft. Fix the surface the seal rides on. A new seal on a grooved shaft will leak again. Read more

GM GENUINE supplies both parts for the 2026 GMC Sierra 3500.

This group includes GM GENUINE 12689006 and GM GENUINE 12689007.

This table covers the oil-control solenoids that command the cam phasers. Typical signs include a door or range that will not move, or a click with no motion. Confirm the command signal before replacing the actuator — a failed module looks the same. Read more

One part is listed for the 2026 GMC Sierra 3500 — GM GENUINE 12675031.

This table covers the seals at the Variable Valve Timing (VVT) Solenoid Gasket. Typical signs include a wet housing, a drip after sitting, or fluid flung off a rotating shaft. Fix the surface the seal rides on. A new seal on a grooved shaft will leak again. Read more

This group shows a single part: GM GENUINE 12623437.

This table covers the cam phaser sprockets used by the variable-valve-timing system. Read more

One part is listed for the 2026 GMC Sierra 3500 — GM GENUINE 12689342.