2025 GMC Sierra 2500 Engine Parts

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

4 Camshaft parts for the 2025 GMC Sierra 2500 come from 2 brands — GM GENUINE and MELLING.

This group includes GM GENUINE 12742436, GM GENUINE 12672469 and GM GENUINE 12633925 and the remaining parts above.

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

6 Camshaft Bearing parts for the 2025 GMC Sierra 2500 come from GM GENUINE.

Listed part numbers: GM GENUINE 19260877, GM GENUINE 19260878 and GM GENUINE 19260879, plus the other parts above.

This table covers the Camshaft bolts. Read more

One part is listed for the 2025 GMC Sierra 2500 — 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

2 Camshaft Retainer / Thrust Plate parts are listed for the 2025 GMC Sierra 2500, from FEL-PRO and GM GENUINE.

Listed part numbers: FEL-PRO ES73115 and GM GENUINE 12589016.

This table covers the connecting rods between each piston and the crankshaft. Read more

This group shows a single part: GM GENUINE 12683616.

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

2 Connecting Rod Bearing parts for the 2025 GMC Sierra 2500 come from GM GENUINE.

Listed part numbers: GM GENUINE 12735504 and GM GENUINE 12685817.

This table covers the Connecting Rod bolts. Read more

One part is listed for the 2025 GMC Sierra 2500 — 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 2025 GMC Sierra 2500 — GM GENUINE 12743331.

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

2 Crankshaft parts for the 2025 GMC Sierra 2500 come from GM GENUINE.

Part numbers include GM GENUINE 12708884 and GM GENUINE 12677566.

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

GM GENUINE supplies both parts for the 2025 GMC Sierra 2500.

This group includes GM GENUINE 12729655 and GM GENUINE 12704537.

This table covers the Crankshaft Main Bearing caps. Typical signs include a leak at the neck, a cap that will not hold pressure, or a missing tether. Match the pressure rating or thread in the notes — radiator, reservoir and fuel caps are not interchangeable. Read more

One part is listed for the 2025 GMC Sierra 2500 — GM GENUINE 12686745.

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

4 Crankshaft Main Bearing Cap Bolt parts for the 2025 GMC Sierra 2500 come from GM GENUINE.

Part numbers include GM GENUINE 11546565, GM GENUINE 11548076 and GM GENUINE 11548075, among others listed above.

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

5 Crankshaft Seal parts are listed for the 2025 GMC Sierra 2500, from GM GENUINE and FEL-PRO.

This group includes FEL-PRO TCS46221, GM GENUINE 12634614 and GM GENUINE 12665076 and the remaining parts above.

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

2 Cylinder Head parts are listed for the 2025 GMC Sierra 2500, from GM GENUINE and QUALCAST.

Listed part numbers: GM GENUINE 12716846 and QUALCAST 16166555.

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 2025 GMC Sierra 2500 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

6 Cylinder Head Gasket parts for the 2025 GMC Sierra 2500 come from 2 brands — GM GENUINE and ENGINE PRO.

Part numbers include ENGINE PRO 2812688186, GM GENUINE 12688186 and GM GENUINE 12747434, among others listed above.

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 2025 GMC Sierra 2500 — GM GENUINE 24502262.

This table covers the Engine Block drain plugs. Read more

4 Engine Block Drain Plug parts for the 2025 GMC Sierra 2500 come from GM GENUINE.

Listed part numbers: GM GENUINE 11602951, GM GENUINE 11546667 and GM GENUINE 11588468, plus the other parts above.

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

GM GENUINE supplies both parts for the 2025 GMC Sierra 2500.

This group includes GM GENUINE 12586687 and GM GENUINE 12742345.

This table covers the Engine covers. Read more

2 Engine Cover parts for the 2025 GMC Sierra 2500 come from 2 brands — TECHPRO and VARIOUS MFR. Every part fits both the 6.6L V8 and the 6.6L V8 DIESEL Turbocharged.

Listed part numbers: TECHPRO GM1228175, plus the other parts above.

This table covers the Engine Cover grommets. Read more

One part is listed for the 2025 GMC Sierra 2500 — GM GENUINE 12594875.

This table covers the Engine Cover retainers and clips. Read more

One part is listed for the 2025 GMC Sierra 2500 — GM GENUINE 11588327.

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

6 Exhaust Valve parts are listed for the 2025 GMC Sierra 2500, from GM GENUINE, MELLING, QUALCAST and 1 other brand.

Part numbers include GM GENUINE 12733470, GM GENUINE 12730002 and MELLING V5828, among others listed above.

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

4 Harmonic Balancer parts for the 2025 GMC Sierra 2500 come from 2 brands — GM GENUINE and SKP.

The Economy section lists 1 option from SKP — the catalog's value-priced group. SKP SK12723412 is listed in this group.

In the Standard Replacement grade, GM GENUINE supplies 2 parts: built to original-equipment specification. A representative part number is GM GENUINE 12692644.

1 further part sits outside the graded sections, with the same engine-level match.

Part numbers include SKP SK12723412, GM GENUINE 12692644 and GM GENUINE 12723412, among others listed above.

This table covers the Harmonic Balancer bolts. Read more

4 Harmonic Balancer Bolt parts are listed for the 2025 GMC Sierra 2500, from GM GENUINE and FEL-PRO.

Listed part numbers: FEL-PRO 73372, GM GENUINE 11547372 and GM GENUINE 11589168, plus the other parts above.

This table covers the Intake insulators. Read more

This group shows a single part: GM GENUINE 84262961.

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

GM GENUINE supplies the 4 Intake Manifold parts for the 2025 GMC Sierra 2500.

This group includes GM GENUINE 12748172, GM GENUINE 12715992 and GM GENUINE 12716585 and the remaining parts above.

This table covers the Intake Manifold bolts. Read more

2 Intake Manifold Bolt parts for the 2025 GMC Sierra 2500 come from GM GENUINE. 1 part fits every engine; the other 1 is engine-specific.

Listed part numbers: GM GENUINE 11610472 and GM GENUINE 11588714.

This table covers the Intake Manifold covers. Read more

This group shows a single part: GM GENUINE 84262962.

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 2025 GMC Sierra 2500 come from GM GENUINE. 1 part fits every engine; the other 2 are engine-specific.

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

This table covers the intake valves that let air (and fuel, on port-injected engines) into 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

3 Intake Valve parts are listed for the 2025 GMC Sierra 2500, from MELLING and SBI.

Part numbers include MELLING V5827, MELLING V3469 and SBI 13469.

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

GM GENUINE supplies the 3 Motor Mount parts for the 2025 GMC Sierra 2500.

This group includes GM GENUINE 85043935, GM GENUINE 84070092 and GM GENUINE 85043936.

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

39 Oil parts are listed for the 2025 GMC Sierra 2500, from VALVOLINE, LUCAS OIL, MOBIL and 3 other brands. ACDELCO 109324 carries the "Popular" badge. They are grouped as Conventional, Full Synthetic, Heavy Duty / Diesel, High Mileage (>75,000 Miles) and Synthetic Blend, with Full Synthetic the largest group at 20 parts from VALVOLINE, LIQUI MOLY, MOBIL and 3 other brands.

This table covers the heat exchangers that cool engine oil. Typical signs include oil at the cooler fittings, or coolant that looks like a milkshake. Pressure-test both circuits after a cooler swap — a leak here mixes oil and coolant. Read more

GM GENUINE supplies both parts for the 2025 GMC Sierra 2500.

Part numbers include GM GENUINE 12675428 and GM GENUINE 12738896.

This table covers the seals at the Oil Cooler Adapter. 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 2025 GMC Sierra 2500.

This group includes GM GENUINE 12676826 and GM GENUINE 12709792.

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

4 Oil Cooler Gasket parts for the 2025 GMC Sierra 2500 come from GM GENUINE.

Listed part numbers: GM GENUINE 23129010, GM GENUINE 12675429 and GM GENUINE 12640849, plus the other parts above.

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 2025 GMC Sierra 2500 — 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

3 Oil Cooler Line Connector parts for the 2025 GMC Sierra 2500 come from GM GENUINE.

Part numbers include GM GENUINE 84240295, GM GENUINE 11588694 and GM GENUINE 11515760.

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

2 Oil Cooler Seal parts for the 2025 GMC Sierra 2500 come from GM GENUINE. 1 part fits every engine; the other 1 is engine-specific.

Listed part numbers: GM GENUINE 12631281 and GM GENUINE 97216175.

This table covers the Oil Dipstick tubes. Read more

GM GENUINE supplies both parts for the 2025 GMC Sierra 2500.

Part numbers include GM GENUINE 12664925 and GM GENUINE 12736677.

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

3 Oil Dipstick / Tube Seal parts for the 2025 GMC Sierra 2500 come from GM GENUINE. 2 parts fit every engine; the other 1 is engine-specific.

This group includes GM GENUINE 24504031, GM GENUINE 12676951 and GM GENUINE 12736679.

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

4 Oil Drain Plug parts are listed for the 2025 GMC Sierra 2500, from DORMAN and GM GENUINE. 3 parts fit every engine; the other 1 is engine-specific.

Part numbers include DORMAN 090948CD, DORMAN 090948 and GM GENUINE 55577568, among others listed above.

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

3 Oil Filler Cap parts are listed for the 2025 GMC Sierra 2500, from ACDELCO and MOTORAD.

This group includes ACDELCO FC279, ACDELCO FC261 and MOTORAD MO190.

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

GM GENUINE supplies both parts for the 2025 GMC Sierra 2500.

Listed part numbers: GM GENUINE 12668614 and GM GENUINE 12695942.

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

11 Oil Filter parts are listed for the 2025 GMC Sierra 2500, from VARIOUS MFR, WIX, ACDELCO and 5 other brands. WIX WL10255XP carries the "Popular" badge. 10 parts fit every engine; the other 1 is engine-specific.

Economy: 4 parts, from FRAM, FVP, PRO-TEC and 1 other brand. A representative part number is FRAM FE10575.

In the High Performance / Heavy Duty grade, WIX and MOBIL 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 WIX WL10255XP.

The Standard Replacement section: 5 options from ACDELCO, WIX, HASTINGS / BALDWIN and 1 other brand. 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

GM GENUINE supplies the 4 Oil Galley Plug parts for the 2025 GMC Sierra 2500.

This group includes GM GENUINE 11546667, GM GENUINE 12651561 and GM GENUINE 09427693 and the remaining parts above.

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 2025 GMC Sierra 2500 — 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 2025 GMC Sierra 2500 — GM GENUINE 12638820.

This table covers the Oil nozzles. Read more

One part is listed for the 2025 GMC Sierra 2500 — GM GENUINE 12678499.

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

3 Oil Pan parts for the 2025 GMC Sierra 2500 come from 3 brands — DORMAN, GM GENUINE and SKP.

Part numbers include DORMAN 264882, GM GENUINE 12739177 and SKP SK264882.

This table covers the Oil Pan bolts. Read more

GM GENUINE supplies the 3 Oil Pan Bolt parts for the 2025 GMC Sierra 2500.

Part numbers include GM GENUINE 12554990, GM GENUINE 11588725 and GM GENUINE 11588713.

This table covers the Oil Pan covers. Read more

One part is listed for the 2025 GMC Sierra 2500 — 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 4 Oil Pan Gasket parts for the 2025 GMC Sierra 2500. 1 part fits every engine; the other 3 are engine-specific.

This group includes GM GENUINE 12666993, GM GENUINE 12623359 and GM GENUINE 12621086 and the remaining parts above.

This table covers the Oil pumps. Typical signs include noise from the pump, no pressure, or fluid that never arrives at the outlet. Prime or fill the pump as the notes require. A dry start is a common way to kill a new unit. Read more

4 Oil Pump parts are listed for the 2025 GMC Sierra 2500, from GM GENUINE and MELLING.

This group includes GM GENUINE 12733670, GM GENUINE 12744612 and GM GENUINE 12731119 and the remaining parts above.

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 2025 GMC Sierra 2500 — 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 pickup tubes and screens that feed the oil pump. Read more

This group shows a single part: GM GENUINE 12706083.

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

One part is listed for the 2025 GMC Sierra 2500 — 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

5 Piston parts for the 2025 GMC Sierra 2500 come from GM GENUINE.

This group includes GM GENUINE 12699527, GM GENUINE 12699528 and GM GENUINE 12699529 and the remaining parts above.

This table covers the Piston Pin retainers. Read more

GM GENUINE supplies both parts for the 2025 GMC Sierra 2500.

Listed part numbers: GM GENUINE 01647383 and GM GENUINE 12656762.

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

3 Piston Ring parts for the 2025 GMC Sierra 2500 come from GM GENUINE.

This group includes GM GENUINE 12735470, GM GENUINE 12661872 and GM GENUINE 12686801.

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

4 Push Rod parts for the 2025 GMC Sierra 2500 come from 3 brands — GM GENUINE, MELLING and SBI.

Part numbers include GM GENUINE 12619828, GM GENUINE 12633924 and MELLING MPR696, among others listed above.

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

5 Rocker Arm parts are listed for the 2025 GMC Sierra 2500, from GM GENUINE, MELLING and SBI.

Part numbers include GM GENUINE 12619829, GM GENUINE 12636189 and GM GENUINE 12636190, among others listed above.

This table covers the Rocker Arm nuts. Read more

This group shows a single part: GM GENUINE 11546449.

This table covers the Rocker Arm shafts. Read more

One part is listed for the 2025 GMC Sierra 2500 — GM GENUINE 12648424.

This table covers the Timing Camshaft Gear bolts. Read more

This group shows a single part: GM GENUINE 11610686.

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

2 Timing Chain parts for the 2025 GMC Sierra 2500 come from 2 brands — GM GENUINE and MELLING.

This group includes GM GENUINE 12646387 and MELLING 3SRH60.

This table covers kits that group a timing chain with the related tensioners and guides. Read more

MELLING supplies both parts for the 2025 GMC Sierra 2500.

This group includes MELLING 33SRH60SX and MELLING 33SRH60SE.

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

3 Timing Chain Tensioner parts are listed for the 2025 GMC Sierra 2500, from GM GENUINE and MELLING. 1 part fits every engine; the other 2 are engine-specific.

Listed part numbers: GM GENUINE 11515758, GM GENUINE 12630107 and MELLING BT5174.

This table covers the Timing covers. Read more

4 Timing Cover parts for the 2025 GMC Sierra 2500 come from 2 brands — GM GENUINE and SKP.

Listed part numbers: GM GENUINE 12691692, GM GENUINE 12734113 and GM GENUINE 12739836, plus the other parts above.

This table covers the Timing Cover bolts. Read more

GM GENUINE supplies both parts for the 2025 GMC Sierra 2500.

This group includes GM GENUINE 11588730 and GM GENUINE 11515759.

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

2 Timing Crank Sprocket parts are listed for the 2025 GMC Sierra 2500, from GM GENUINE and MELLING.

This group includes GM GENUINE 12713934 and MELLING S1355.