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2026 Ram Ram 2500

Reliability tier: verified - see /disclosure/

Engine: 6.4L V8 Gas (392 HEMI) (Hemi, 6.4L), 2v

OHV pushrod 16-valve V8, deep-skirt cast-iron block/aluminum heads, sequential multiport fuel injection, MDS cylinder deactivation is fitted (deactivating lifters on cylinders 1/4/6/7) - the HD shares the HEMI MDS architecture; 405hp @ 5,800 / 429 lb-ft @ 4,200; 66RFE 6-speed or 68RFE/AS69RC behind it (context only). Gas option on the new-generation Ram HD body alongside the 6.7 Cummins. Catalog-coverage note: the Mopar dealer catalog was checked through model year 2025 on 2026-09-29 (2025 lineup still offers the 6.4); 2026 config is spec-based.

Applicable failure modes (6)

• Cooling service (water pump / thermostat)
• EGR valve carbon (gas EGR service surface)
• Exhaust manifold bolt failure / leaks (HEMI tick source #1)
• Fuel delivery service (in-tank pump / PFI injectors)
• Ignition service wear (plugs / coils)
• Lifter / cam wear (HEMI tick source #2)

Applicable parts (22)

• 6.4L HEMI Camshaft Position Sensor (OEM)
• 6.4L HEMI Coolant Temperature Sensor (OEM)
• 6.4L HEMI Crankshaft Position Sensor (OEM)
• ram-hemi-6_4: emissions (service item)
• 6.4L HEMI Exhaust Manifold Bolt (OEM)
• 6.4L HEMI Exhaust Manifold Gasket (OEM)
• 6.4L HEMI Exhaust Manifold, left (OEM)
• 6.4L HEMI Exhaust Manifold, right (OEM)
• 6.4L HEMI Fan Clutch (OEM)
• 6.4L HEMI Fuel Pump / Sender Module, 2021+ (OEM)
• 6.4L HEMI Head Gasket (OEM, per bank)
• 6.4L HEMI Ignition Coil (OEM)
• 6.4L HEMI Valve Lifter (OEM, all-years listing)
• 6.4L HEMI Hydraulic Roller Lifter, deactivating (MDS, OEM)
• 6.4L HEMI Hydraulic Roller Lifter, standard yoke (OEM)
• 6.4L HEMI Oil Pressure Sensor (OEM)
• 6.4L HEMI Oxygen Sensor, front (OEM)
• 6.4L HEMI Push Rod (OEM)
• 6.4L HEMI Rocker Arm (OEM, per position)
• 6.4L HEMI Spark Plug (OEM)
• 6.4L HEMI Thermostat Housing (OEM)
• 6.4L HEMI Valve Cover Gasket (OEM)

Platform recipes (3)

• Exhaust manifold repair for the 6.4L HEMI (mode fm-h64-exhaust-manifold-bolts) - the platform's signature failure: manifold bolts stretch/break and the leak reads as a cold-start tick
• Ignition service for the 6.4L HEMI (mode fm-h64-ignition-service): 16 plugs on the OHV V8, one coil per cylinder, MDS runs under the covers
• Lifter/valvetrain repair for the 6.4L HEMI (mode fm-h64-lifter-cam-wear): the 6.4 HAS MDS - deactivating lifters (5038788AD) sit beside standard ones (5038787AD), and a failed deactivating lifter reads as a cold-start tick plus an MDS DTC