Oil-Ram trucks use the Stellantis Mopar MS-6395 oil specification. The combination of massive HEMI V8 engines with cylinder deactivation, eTorque mild hybrid systems, and heavy-duty towing demands makes correct oil choice critical for Ram truck longevity.
Mopar MS-6395 — Required for All Ram Petrol Engines
Mopar MS-6395 is the mandatory specification for all Ram petrol engines. It exceeds API SP with additional tests for LSPI prevention, oxidation stability, and timing chain wear. The Ram 1500 5.7L HEMI requires SAE 0W-20 — a surprisingly thin oil for a 5.7-litre V8, chosen because modern tight-tolerance engines achieve better fuel economy and cold-start protection with low-viscosity oil. The 3.6L Pentastar V6 in the Ram 1500 Classic also uses 0W-20.
HEMI V8 — MDS Lifter Protection
The 5.7L HEMI in the Ram 1500 uses Multi-Displacement System (MDS) to deactivate four of eight cylinders under light loads. The hydraulic MDS lifters are the most failure-prone component in the HEMI — they require consistent oil pressure and quality to engage and disengage thousands of times per journey. Lifter failure causes a distinctive ticking noise, misfires, and can damage the camshaft. Using MS-6395 approved SAE 0W-20 synthetic oil and maintaining strict change intervals is the best preventive measure.
eTorque — Mild Hybrid V8 Oil Considerations
Ram's eTorque system adds a 48V belt-driven motor-generator to the HEMI V8, enabling stop-start functionality and torque filling during cylinder deactivation transitions. The frequent engine stop-start cycles mean the oil must maintain film strength during brief shutdown periods and provide instant protection on restart. The eTorque HEMI uses the same SAE 0W-20 MS-6395 oil as the non-eTorque version — no different specification is required.
0W-20 in a V8 — Why It Works
Many Ram owners question using SAE 0W-20 in a large V8 engine. The key is that modern HEMI engines are machined to much tighter tolerances than older V8s — bearing clearances are designed for thin oil. The 0W-20 grade provides faster oil flow at startup (reducing the critical dry-start wear period), lower pumping losses, and reduced viscous drag. The synthetic base stocks maintain adequate film strength at operating temperature. Using thicker oil (5W-30, 5W-40) actually increases wear by reducing oil flow through tight clearances and can cause MDS lifter issues.
Heavy Towing — Severe Service Protocol
Ram trucks frequently tow heavy loads — the Ram 1500 is rated up to 12,750 lbs. Towing generates extreme oil temperatures and loads. Ram recommends the Oil Life Monitor system, but for trucks that regularly tow near capacity, many dealers advise 5,000-mile intervals. The maximum interval is 10,000 miles or one year. Always use SAE 0W-20 meeting MS-6395, even under severe conditions — do not switch to a thicker viscosity for towing.